Engineering system and method of automatic controlling of the energy efficient mode of pipeline transporting process of fluid medium
12111019 ยท 2024-10-08
Assignee
Inventors
Cpc classification
F15D1/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F17D1/20
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F17D5/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B65G53/04
PERFORMING OPERATIONS; TRANSPORTING
B65G53/28
PERFORMING OPERATIONS; TRANSPORTING
F17D1/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F17D3/01
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B65G53/30
PERFORMING OPERATIONS; TRANSPORTING
International classification
F17D1/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F17D1/20
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F17D3/01
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
An engineering system, comprising a pumping system, a wave system, a system of measuring devices, and a dynamic controller, configured for generating pressure waves with controlled frequencies, and their propagating through turbulent flow in the suction and discharge pipelines of the pumping system. The engineering system performs a method of automatic controlling the energy efficient mode of pipeline transporting of fluid medium. The dynamic controller regulates and adjusts in real time optimal values of frequencies of generating pressure waves, providing minimum values of hydrodynamic resistance of turbulent flow in the discharge pipeline, for any average value of the flow velocity, compared to the hydrodynamic resistance of the turbulent flow having the same velocity, but not interacting with pressure waves. Automatic controlling the process of generating pressure waves with optimal frequencies by the dynamic controller, ensures the maximum energy efficiency of the process of pipeline transporting of fluid medium.
Claims
1. An engineering system for pipeline transporting process of fluid medium comprising systems: a pumping system, comprising: a pump, having an inlet and an outlet, a suction pipeline and a discharge pipeline, wherein the inlet is connected to the suction pipeline and the outlet is connected to the discharge pipeline, a motor, coupled to a pump, the pumping system is configured to pump flow medium through the suction pipeline, the pump, and the discharge pipeline; a wave system, comprising: a pressure waves generator, a motor, connected to the pressure waves generator, connecting pipes connecting the pressure waves generator parallel to the pump, to the suction pipeline and the discharge pipeline, the wave system is configured for generating pressure waves; a system for generating pressure waves, formed from the interconnected the pumping system and the wave system, configured in such a way, that during the operating pumping system and wave system, pressure waves are generating by pressure waves generator, and propagating through the medium flow in the connecting pipes, the suction pipeline, and the discharge pipeline; a system of measurement devices, comprising: measurement devices set on the elements of the system for generating pressure waves, connected to an input module of a dynamic controller, and configured for measuring current values of operating parameters of the turbulent flow, of the motor of pressure waves generator, and of the pressure waves; a dynamic controller, connected to the feedback of the system for generating pressure waves, comprising: a microprocessor, a memory, an input module, an output module, output-controlled devices, a programming device; the input module is connected to measurement devices; the microprocessor is interconnected to the input module, the memory, the programming device, and the output module; the output module is connected to the output-controlled devices; the dynamic controller is configured for providing in real-time the automatic controlling of energy efficient mode of the process of pipeline transporting of fluid medium through the pumping system.
2. The engineering system according to claim 1, wherein the ratio of the cross-sectional area of the connecting pipe to cross-sectional area of the discharge pipe is less than 0.04.
3. The engineering system according to claim 1, wherein each of connecting pipe of the pressure waves generator is equipped with a controlled valve.
4. The engineering system according to claim 3, wherein each control valve is connected to the input module of the dynamic controller.
5. A method of automatic controlling of energy efficient mode of the process of pipeline transporting of fluid medium performed by the engineering system, comprising the steps of: computing the optimal average values of frequencies of pressure waves interacting with turbulent flow in a pipe, providing the minimum average values of the hydrodynamic resistance coefficient for a discrete set of current average values of the flow velocities, covering an entire practical range; experimental checking and correcting of the computed minimum average values of the hydrodynamic resistance coefficient at average values of optimal frequencies of generated pressure waves, for the discrete set of said average values of the flow velocities; compiling the baseline file containing: a discrete set of said average values of the flow velocities; a discrete set of the average values of computed and experimentally corrected minimum values of the hydrodynamic resistance coefficient at average values of optimal frequencies of generated pressure waves for said discrete set of current average values of the flow velocities; uploading the baseline file in the memory of the dynamic controller; measuring current values of the flow velocity, current of the pressure waves generator motor, optimal frequencies of generated pressure waves, and pressures in the discharge pipeline and in the suction pipeline; transmitting the current values of said measured parameters to the input module; converting the transmitted current values of said measured parameters in the digital format by the input module; transmitting the digital format of said measured parameters to the microprocessor; providing receiving, recording, processing, calculating, and saving current values of the flow velocity, current of the pressure waves generator motor, optimal frequencies of generated pressure waves, and pressures in the discharge pipeline and in the suction pipeline, by the microprocessor; averaging the received current values of the flow velocity, current of the pressure waves generator motor, optimal frequency of generated pressure waves, pressures in the discharge pipeline and suction pipeline, and calculated parameters at each specified time interval; compiling the file of average parameters containing updated average values of the flow velocity, current of the pressure waves generator motor, optimal frequencies of pressure waves, and pressures in the discharge pipeline and in the suction pipeline; selecting the row in the baseline file, considering pressure waves action on the turbulent flow, in which the average value of the flow velocity is closest to the last updated average value of the flow velocity from the file of average parameters; transmitting average value of the current of pressure waves generator motor from the selected row of said baseline file to the output module; converting the received average value of the current of pressure waves generator motor into analog signal; transmitting the value of analog signal to the automatic controlled-device; changing the value of operating current of the motor of pressure waves generator motor to the transmitted optimal average value of the current, from the baseline file, corresponding to current value of the flow velocity in the discharge pipeline, optimal frequency of pressure waves, and minimum value of the hydrodynamic resistance coefficient; providing the energy efficient mode of the process of pipeline transporting of fluid medium.
6. The method according to claim 5 wherein the correcting amplitude of generated pressure waves is performed by variation of the valve opening angle.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) To facilitate a complete understanding of the proposed invention, it is useful to simultaneously analyze the text of the Detailed Description and accompanying the proposed drawings.
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DETAILED DESCRIPTION OF THE INVENTION
(15) The current invention provides an engineering system and method of automatic controlling of the energy efficient mode of pipeline transporting process of fluid medium.
(16) The detailed description offered below does not consider all the details of each of the systems that comprise the engineering system, but sufficient, for understanding the operation of the engineering system. In the detailed description of the method, some nonessential actions are also omitted, which do not affect the essence and sequence of the steps of the practical realization of the method.
(17) In modern pumping systems the pipeline transportation of fluid media is carried out by a pump that provides a stationary pressure gradient along the discharge pipeline.
(18) Attempts to decrease the hydrodynamic resistance of the turbulent flow in a pipeline with the use of a source of additional perturbations of the flow velocity or pressure, such as artificial turbulators installed on the inner surfaces of the pipes that have a local effect. Therefore, they did not find industrial applications.
(19) The use of negative modulation of the flow-forming energy makes it possible to generate the controlled pressure waves of small amplitudes and low frequencies, and ensure their propagation through the flow of the transported medium in long pipelines.
(20) The interaction of pressure waves of suitable amplitudes and frequencies with the turbulent medium flow in the pipeline, ensures a decrease in hydrodynamic resistance. Therefore, the development of a method for automatic controlling of the energy efficiency of the process of pipeline transporting of flow medium by controlling amplitudes and frequencies of generated pressure waves is fundamental for industrial applications.
(21) To facilitate a complete understanding of the proposed invention, it is useful to study simultaneously the text of the Detailed Description, accompanied by the proposed drawings.
(22) The current invention provides an engineering system and a method of automatic controlling of the energy efficient mode of pipeline transporting process of fluid medium. The engineering system, performing the energy efficient mode, is designed for pipeline transportation of fluid medium and comprises the following interconnected systems: a pumping system; a wave system; a system for generating pressure waves; a system of measurement devices; a dynamic controller.
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(24) A wave system 7,
(25) The wave system is designed to provide the set dynamic law of change of connecting surface over time, S.sub.C(t) during a period, T. The law S.sub.C(t) defines the law of change of pressure over time in the generated wave, P.sup.?(t).
(26) Calculated values of parameters of the generated waves depend on: physical properties of the fluid medium (density ?, viscosity ?, compressibility ?, temperature t.sub.f); operating parameters (flow velocity ?, suction pressure P.sub.sp, and discharge pressure P.sub.dp on the pump); geometrical parameters (diameters of the suction and discharge pipeline and of connecting pipes).
(27) Based on these parameters, the geometric shapes, and sizes of profiles of the openings in the walls of coaxially located cylindrical elements of the PWG are selected and calculated. During rotation of the inner cylinder relative to the outer cylinder, the intersection of the surfaces of the specified openings is carried out (details, U.S. Pat. No. 10,233,952). As a result of such intersecting, a connecting surface is formed, S.sub.C(t). It connects two volumes belonging to PWG: inner, with the suction pressure, P.sub.S and outer, with the discharge pressure, P.sub.D. During the frontal time, t.sub.F the value of connecting surface increases from zero to maximum value, of the given law, S.sub.F(t): t=0 . . . t.sub.F. During the back time, t.sub.B the value of connecting surface decreases from maximum value to zero, according to a given law, S.sub.B(t): t=t.sub.F . . . T. The law of change of the connecting surface S.sub.F(t) and S.sub.B(t) over time, pressures P.sub.S and P.sub.D, and a speed of the PWG motor, ? define the law of change of pressure over time in the generated pressure waves, P.sup.?.sub.F(t) and P.sup.?.sub.B(t), t=0 . . . t.sub.F . . . T.
(28) A compression wave is generated in a similar way.
(29) A system for generating pressure waves comprising the interconnected pumping system 1 and the wave system 7, schematically presented in the
(30) Physical meaning and design choice of the slope angles ? and ? between connecting pipes 12 and 11 and the suction and discharge pipes, 5 and 6 respectively, are presented by B. Pierre (Pressure Waves in Pipelines and Impulse Pumping. Physical Principles, Model Development and Numerical Simulation, Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology, Trondheim, December 2009).
(31) The process of generating waves is carried out as follows: suppose, that at the initial moment of time the value of the connecting surface is zero, S.sub.C(t)=0. When the motor 3 of a pump 2 is turned on, this system operates as a traditional pumping system 1 for transporting of fluid medium through the suction pipeline 5, the pump 2, and the discharge pipeline 6. When the PWG 8 is turned on, connecting surface becomes greater than zero, changes over time, linking volumes of medium with different pressures: inner volume with the suction pressure, P.sub.S and outer volume with the discharge pressure, P.sub.D. As a result of connecting volumes, an exchange of pressure impulse between them occurs. This process is accompanied by the simultaneous formation of compression and rarefaction pressure waves. The compression pressure wave P.sup.+(t) propagates through the connecting pipe 12 in the suction pipeline 5; the rarefaction pressure wave P.sup.?(t) propagates through the connecting pipe 11 in the discharge pipeline 6. A compression pressure wave, P.sup.+(t) is forming relatively to the suction pressure, P.sub.S, a rarefaction wave, P.sup.?(t) is forming relatively to the discharge pressure, P.sub.D,
(32) When the waves frequency changes, at constant pressures P.sub.S and P.sub.D between zones, the wave amplitude changes too. Indeed, the estimated value of the exchange of pressure impulse, passing perpendicularly to connecting surface S.sub.C(t) is:
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(35) The dynamic structure of turbulence and boundary layer of a medium flow of a given flow rate, <G.sub.j>??G(t), or flow velocity, <?.sub.i>???, interacting with pressure waves only of certain parameters, <P.sup.?>??P.sup.?(t), <?>???(t), <?>???(t), causes the physical effects described above that lead to decrease in the hydrodynamic resistance coefficient, ?.sub.W. The sign < > means the average value of parameter over a given averaging time interval ?t, containing a sufficient number of periods of pressure waves; ?G(t), ?P.sup.?(t), ?f(t), and ??(t) are dynamic deviations from the average values of the indicated parameters, during operating engineering system for pipeline transporting of fluid medium.
(36) Automatic control of the feedback between current value of the state of turbulent flow and parameters of generated waves is performed by the dynamic controller. The essence of this control is providing the continuous controlling frequency of generating pressure waves providing the decrease of hydrodynamic resistance of the current value of the flow rate.
(37) A system of measurement devices comprising measurement devices, installed on the elements of the engineering system, and connected to the dynamic controller,
(38) Each device is configured to measure the current value of parameter and to display on the screen the digital value of measured parameter in the standard or engineering units. For example: pressure can be displayed in Pa, Bar, atm; flow rate can be displayed in GPM, m.sup.3/s, m.sup.3/h.
(39) Speed of the pump impeller can be measured directly, by tachometer 25,
(40) To ensure high accuracy of the frequency of the generated waves, in the wave system 7 a brushless motor 9 is used. It also smooths out the unevenness of the torque that occurs during operation of the PWG 8. The angular speed of the shaft 10 of the PWG 8 is determined by the torque-speed characteristic of the motor 9, measured by motor current, or by tachometer 27,
(41) Accuracy of measurement devices is an important requirement. Usually, digital measurement devices in the control system are used and most of them are already operating at any pumping station, except for measurement devices of the wave system. If among the measurement devices there are analog once, then the input module of dynamic controller converts analog signals into digital ones.
(42) During operation of the engineering system of the process of pipeline transporting of fluid medium, each measurement device shows instantaneous value of the current parameter, for example, flow rate G, pressure P.sub.D at the inlet of the discharge pipeline. All measurement devices are set to the same interval of time for updating values of measured parameters. In a particular case, the updated time interval of measured parameter can be changed. For example, for detailed analysis of the change of pressure over time in the wave, during a period, on a pressure sensor display, a shorter updated time interval is set.
(43) Power of the pump motor can be calculated using measured value of the current and standard voltage. This power can also be measured by watt meter. In this case, a watt meter is connected to the motor circuit. Usually, in a pumping stations both of these measurement devices are connected and installed on the control panel.
(44) The current values of the measured parameters change over time, under the influence of weak pressure and flow rate trends that exist in long pipelines, as well as more rough changes in flow rate caused by users. And in the case of the interaction of a turbulent flow with pressure waves, the dynamics and structure of the boundary layer are changed; the spectrum of turbulent fluctuations of the flow velocity and pressure, as well as macroscopic measured parameters, for example, the flow rate G and pressure P.sub.D, also are changed. These structural-dynamic changes in the turbulent flow, lead to change in turbulent viscosity and consequently, in the hydrodynamic resistance coefficient, ?.sub.W and the energy efficiency, E.sub.fW. The process of real-time controlling of the structural changes or dynamic state of the turbulent flow is determined by the frequency and amplitude of pressure waves interacting with the flow. Practically, this is carried out automatically by the PWG motor, based on the software data processing the measured current values of the flow parameters: flow velocity ?, measured by a flowmeter and calculated by ?=G/S; discharge P.sub.D and suction P.sub.S pressures, and hydrodynamic resistance coefficient, ?.sub.W.
(45) Usually, the updated time interval, ?t of the measured parameter(s), for example, of the flow rate, is quite short (of the order of tens ms) compared with the time interval ?.sub.W of responses of the output-controlled device and of the wave unit. Therefore, to control the wave unit using dynamic controller 17 with the output-controlled device 20, it is necessary to increase the duration of the time of the supplying current to the motor 9 of the PWG to the order of ?.sub.W. This requirement also relates to averaging time interval of the basic measured independent argument, flow rate. For satisfying the above specified condition, consider the next relation between time intervals: [m ?t]>?.sub.W, where m is an integer. The discrete function G.sub.Wj (i ?t), i=1, 2 . . . m, measured at the points ?t, 2 ?t . . . m ?t is converted into a continuous function on the same averaging time interval [m ?t], as a result of the simple averaging.
(46)
G.sub.1[(rm+i)?t]=<G.sub.j>??G.sub.j[(rm+i)?t].(7) t.sub.i?[(rm+i)?t], j=1, 2 . . . n, r=0, 1, 2 . . . N is the sequence of numbers of the averaging time intervals [m?t]. A starting of time count is performed from some reference point of counting. For example: i=1, 2 . . . m. r=0: t=1?t, 2?t . . . m ?t; ?G.sub.j(1?t), ?G.sub.j (2*?t) . . . ?G i (m ?t). r=1:t=(m+1)?t, (m+2)?t . . . (m+m)?t; ?G.sub.j [(m+1)?t], ?G.sub.j[(m+2)?t] . . . ?G.sub.j[(m+m)?t]. r=2: t=(2m+1)?t, (2m+2)?t . . . (2m+m)?t; ?G.sub.(j?1)[(2m+1)?t], ?G.sub.(j?1) [(2m+2)?t] . . . ?G.sub.(j?1)[(2m+m)?t].Math.m<N.
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(48) To assist with the understanding of the discussion of the present invention, the following definitions are provided: a controlled system, is the turbulent flow in a discharge pipeline, described by the state parameters: flow velocity, temperature, turbulence structure. a control function, is a pressure wave of the given amplitude and frequency, generated by PWG, and propagated through the turbulent flow in a discharge pipeline.
(49) The need to use the flow velocity in the process of automatic control of energy efficient mode is obviously. A pressure wave interacts with a turbulent flow in the discharge pipeline, which is uniquely described by the flow velocity, not by the flow rate. It is the flow velocity that determines structure and dynamic state of the boundary layer and intensity of turbulent pulsations, which interact with the pressure waves and lead to decrease in the normal components of pulsations, change the specter of turbulent pulsations, anizotropization of turbulence, i.e., to partial laminarization. Ultimately, all these phenomena lead to decrease of hydrodynamic resistance.
(50) However, the main parameter of any pipeline transportation system is the flow rate. This is a basic technological parameter and easily measured with high accuracy. Therefore, in the proposed invention, all measured parameters depend on the flow rate, explicitly or implicitly. However, the physical parameters that underlie the interaction of pressure waves with turbulent flow leading to a change in the state of the controlled system should be considered the flow velocity, both in the description of the patent and in the claims.
(51) The structure of the turbulent flow, and hence, the hydrodynamic resistance coefficient changes when pressure waves interact with the turbulent flow in the pipeline. The frequency of pressure waves controls the internal structure of the turbulent flow. At a certain frequency, the hydrodynamic resistance coefficient, corresponding to current value of the flow rate, reaches a minimum. This frequency is called optimal and corresponds to the energy efficient mode of the pipeline transporting process of flow medium.
(52) Presentation of the measured flow rate in the form (7), is the first step towards the implementing the process of automatic controlling of the energy efficient mode of pipeline transporting process of flow medium. Measuring the flow rate in real time, means the measuring of the state parameters of turbulent flow. State parameters define the structure of turbulent flow and boundary layer, which determine the value of the hydrodynamic resistance coefficient, ?.sub.W. The remaining measured and computed energy and dynamic parameters of the turbulent flow, presented in TABLE 2, are considered as functions of the flow rate.
(53) Power of the PWG motor can be calculated using measured value of the current and voltage, usually low constant voltage. This power can also be measured by wattmeter. In this case in the circuit the of the PWG motor a watt meter is connected.
(54) Below, we will consider only such average functions of the averaging time interval [m ?t], which are obtained as a result of measuring instantaneous values of parameters: flow rate, waves frequency, speed of the pump impeller etc. The value of ratio [m ?t]/?.sub.W acquires an important role in the process of automatic controlling of the energy efficient mode.
(55) The measured current values of parameters are transmitted to the input module of dynamic controller.
(56) A dynamic controller 17,
(57) A simplified block diagram of the dynamic controller is presented in the
(58) The dynamic controller 17 can be used for the pump control, for example, with the constant pump RPM using a controlled-device 22, without operating the wave system.
(59) The dynamic controller is configured also for manual operating mode. This means that the user can manually change or fix the current of the pump motor, current of the motor of the PWG, controlling the frequency of generated waves, and valve opening angle of the control valves.
(60) Before proceeding to the description of the method of energy efficient mode of pipeline transporting process of fluid medium, let us consider the database that is the basis for development of the program to implement the method of automatic controlling of this mode.
(61) The essence of this database is to simulate the turbulent motion of a fluid medium using the Navier-Stokes equation, under the action of the constant pressure and of the perturbed pressure by pressure waves, in the flow domain belonging to a straight horizontal pipeline section with a given constant cross section,
(62) These two sets constitute the database for the baseline file which is used for the comparative analysis of the states of controlled system when the control function is changing.
(63) Next, the energy efficiency E.sub.f and ?.sub.fW are calculated and compared. Modeling is carried out using a sufficiently accurate computational tool, for example, Large Eddy Simulation (LES), which is widely used in Computational Fluid Dynamics (CFD). Calculations are carried out over the entire practical range of the flow velocity and consequently, of the Reynolds numbers.
(64) Obtaining the Baseline Data for the Turbulent Flow Under the Action of the Constant Discharge Pressure.
(65) The flow domain of horizontal cylindrical form,
(66) Experimental verification of the hydrodynamic resistance coefficient, ? obtained as a result of the LES, is carried out as follows: a horizontal experimental section of the pipeline with a length L and a diameter D is selected, at the distance of more than 35 pipe diameters downstream from the conjugation surface S.sub.D,
(67) In the process of experimentation, the error of all measuring devices is determined. The final corrected results are presented in TABLE 1.
(68) TABLE-US-00001 TABLE 1 Baseline data. P.sub.D = const. j G.sub.j ?.sub.j Re.sub.j Ps.sub.j P.sub.Dj I.sub.j ?.sub.j N.sub.Pj ?.sub.j V.sub.j E.sub.fj 1 G.sub.1 ?.sub.1 Re.sub.1 Ps.sub.1 P.sub.D1 I.sub.1 ?.sub.1 N.sub.1 ?.sub.1 V.sub.1 E.sub.f1 2 G.sub.2 ?.sub.2 Re.sub.2 Ps.sub.2 P.sub.D2 I.sub.2 ?.sub.2 N.sub.2 ?.sub.2 V.sub.2 E.sub.f2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . q G.sub.q ?.sub.q Re.sub.q Ps.sub.q P.sub.Dq I.sub.q ?.sub.q N.sub.q ?.sub.q V.sub.q E.sub.fq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . n G.sub.n ?.sub.n Re.sub.n Ps.sub.n P.sub.Dn I.sub.n ?.sub.n N.sub.n ?.sub.n V.sub.n E.sub.fn
(69) These results constitute the baseline data (reference data) for the turbulent motion of the fluid medium in a pipeline, under the action of stationary pressure, P.sub.D=const. In essence, the baseline data at constant pressure is the table function in which, the measured independent argument is the flow rate, G.sub.j, j=1, 2 . . . n. This is the basic measurable technological parameter. The remaining parameters presented in the columns of the TABLE 1 are functions, dependent on the flow rate. Moreover, some of them are measured, and some are computed using values of measured parameters. For example, the flow velocity, ?.sub.j=G.sub.j/S, S is the cross-sectional area of the flow domain (pipe); S=S.sub.i=S.sub.o,
(70) This is the baseline file, considering the action of constant pressure on the turbulent flow in the discharge pipeline. It is developed by programming device 35, is uploaded and is stored in the memory 34 of the dynamic controller 17.
(71) It is obvious, that the main measurable flow parameter, flow rate G.sub.j (TABLE 1), is easily generalized to other similar flows, using the Reynolds similarity criterion, Re.sub.j=4 G/?D?=?.sub.jD/?. For example, if the kinematic viscosity of the main flow and of a similar flow are equal, then from the condition of similarity of flows it follows: ?.sub.j/D.sub.j=?.sub.?/D.sub.?. This condition can be generalized to flows with other pipe diameters and the entire practical range of the flow velocity. Subscript ? relates to parameters of the similar flow. Pressures P.sub.S and P.sub.D, as well as parameters of the pump, Q j and the pump motor, I.sub.j, N.sub.Pj, clearly depend on the flow rate, diameter and length of the pipeline, and also on its configuration, bends and elevation. Parameters Psi, P.sub.Dj, I.sub.j, ?.sub.j, N.sub.Pj, G.sub.j, are intrinsic parameters of the pumping system. They serve to determine the energy and power parameters of the pumping system, for example, calculating the energy efficiency E.sub.f, of the pipeline transporting process of flow medium, using (1). They also serve to monitor the operating dynamics and stability of the pumping system. Therefore, intrinsic parameters of the pumping system are added as data points to the baseline file, TABLE 1.
(72) The increase of energy efficiency of perturbed turbulent flow by pressure waves is carried out not only explicitly, due to the decrease of hydrodynamic resistance, but also implicitly, due to the change in flow rate.
(73) Obtaining the Baseline Data for the Turbulent Flow Under the Action of Perturbed Discharge Pressure by Pressure Waves.
(74) The purpose of this baseline data is to compute the optimal values of frequencies, <?.sub.opt j>.sub.opt and amplitudes,
(75) The configuration of flow domain is selected in such a way, that the physical picture of the simulated interaction of pressure waves with the turbulent flow in the pipeline is as close as possible to the real case scenario.
(76) Flow domain,
(77) To identify the effects of decreasing, and further minimizing the hydrodynamic resistance of the flow domain, operating boundary conditions are used. On the surfaces bounding the flow domain the following boundary conditions are inserted: on the S.sub.I, a mass flow rate; on the S.sub.O, pressure; on the surfaces S.sub.F and S.sub.CP, the no-slip conditions of the flow velocity; on the surface SW, the pressure wave action, P.sub.S.sup.?(t). Pressure P.sub.S.sup.?(t) is changed by the wave law relatively to the discharge pressure P.sub.D,
(78) The essence of the LES simulation is to compute the optimal frequency, ?.sub.opt j=<?.sub.optj>???.sub.j corresponding to current value of the flow velocity ?.sub.Wj [(rm+i)?t]=<?.sub.Wj>???.sub.Wj[(rm+i)?t)] or flow rate, G.sub.Wj[(rm+i)?t]=<G.sub.Wj>T ?G.sub.Wj [(rm+i)?t)], which provides the minimum value of the hydrodynamic resistance coefficient,
[?.sub.j?(
(79) Note, that inequality (8) is satisfied in a certain range of the flow rate changes. In practice, this means that there is a certain range of waves frequencies changes corresponding to a certain range of flow rate changes in which inequality (8) is satisfied. Under the action of pressure waves, the stabilized state of turbulent flow is provided. This is a fundamental principle in the process of automatic controlling of dynamic systems, that the turbulent flow is interacting with pressure waves.
(80) It is this correspondence between the frequency
(81) If LES is performed on another computer, then the results are uploaded into the programming device 35.
(82) The simulation results are verified and corrected on the laboratory hydrodynamic loop. Boundary conditions used on the surfaces S.sub.I and S.sub.W of the flow domain during the process of LES simulation are practically realized as follows: 1. the fluid flow and pressure applied to the S.sub.i surface is provided by a pump; 2. the frequency of the generated pressure waves, set on the surface S.sub.W,
(83) If the amplitude of the generated pressure waves obtained as a result of the LES is not enough to provide the minimum values of hydrodynamic resistance
(84) Experimentally, the hydrodynamic resistance coefficients ?.sub.j and
(85) Inequality (8) imposes the following condition on energy efficiency:
[E.sub.fj?(?.sub.fwj.sup.min)]<?.sub.E,(9) where ?.sub.E is the lower acceptable limit of energy efficiency.
(86) Inequality (9) is based on experimental measured parameters and is used for laboratory testing of simulated results. It is also used by the program for providing the proposed method of automatic controlling of the energy efficient mode in an industrial environment, by the use of current measured parameters of the system for generating pressure waves. AE is set practically. Its estimated value is based on the configuration of the pipeline, physical properties of the flow medium, and of the flow rate.
(87) The sketch of laboratory hydrodynamic loop is similar to one represented on the
?G.sub.Wj+1=?G.sub.Wj=?G.sub.W=const1, j=1, 2 . . . n.(10)
(88) Equality (10) is a fundamental condition in terms of the program for implementation of the method of automatic controlling of energy efficient mode of pipeline transporting process of the flow medium. The condition of cross-linking (10) at the ends of any two successive intervals ?G.sub.Wj and ?G.sub.W+1 is required. An example of this condition, for scenarios a) and c),
(89) If the flow rate in the pipeline changes significantly, for example, for technological needs, then the average values of the flow rate change over time until another stationary state is stabilized,
??.sub.Wj???.sub.Wj+1, j=1, 2 . . . n.(11)
(90) This means, that for different optimal frequencies, the intervals of deviation from the average value differ. This is schematically represented in
(91) Thus, the results of the LES are corrected experimentally.
(92) In the process of experimental correction of simulated parameters in laboratory conditions and further in industrial environment, the number of experimental points m is much greater than indicated in
(93) Experimental laboratory correcting of computed parameters is carried out as follows: if the diameter of the pipeline is equal to diameter of the simulated flow domain, then, the function
(94) The deviations of the measured instantaneous values of parameters from the average are due to the dynamic changes of turbulent flow, actual process of generating waves, as well as the accuracy of measuring devices. The deviations of the measured instantaneous values of parameters from the average, for example, of the flow rate, ?G(i ?t), over an averaging time interval [m ?t], are located in a fairly wide range. A part of deviations belong to the interval, ?G(i?t)?[
1.
2.
3. G.sub.Wj+1, if ?G(i?t)>G.sub.Wj+?G.sub.W.(12)
(95) By substituting
(96) Thus, the experimentally measured average values of
(97) Such a complementary approach, theoretical and experimental, is aimed to defining the corrected control function
(98) All measured and calculated parameters are recorded in the baseline file. Computed and experimental results are corrected. The final corrected results are presented in the TABLE 2; for any j, j=1, 2 . . . n:
(99) These results constitute the baseline data for the turbulent motion of the fluid medium in a discharge pipeline, interacting with pressure waves. Part of the baseline data is obtained by recording parameters from measurement devices, the next part has been obtained as a result of computer simulation, and the last part is computed. Each computed parameter is linear related to some measured parameter. For example, the flow velocity,
(100) Average measured and computed parameters presented in the TABLE 2 are recorded in the baseline file. Further, all n rows in the baseline file are sorted in ascending order of the average values of the flow rate
(101) The proposed method of automatic control of energy efficient mode uses only average values of measured parameters over an averaging time interval [m?t]. Sources and magnitude of deviations of measured values from the average, will not be analyzed and considered.
(102) Considering the action of pressure waves on the turbulent flow, a baseline file is created by using programming device 35, which is uploaded and stored in the memory 34 of the dynamic controller 17. The program, developed for implementation of the method of automatic controlling of the energy efficient mode is installed in the microprocessor 33. The program processes the received data from measurement devices, and can use any parameter of the baseline files for calibrating, correcting, and comparing the measured parameters with the parameters of the baseline files.
(103) The data contained in the baseline files is used during the process of automatic controlling of energy efficient mode.
(104) In TABLE 2, more columns can be added. For example: the column comparing the energy efficiency E.sub.fj and ?.sub.fWj during a day, a week, a month; column of the cost of pipeline transportation of a volume of fluid medium, in energy efficient mode and in the normal mode during a day, a week, a month; column (E.sub.fj??.sub.fj) provides an estimated quantity of saved energy.
(105) Experimental studies carried out on a laboratory hydrodynamic loop show that the power component N.sub.e in balance equation (4) is about ?0.1% of the pump power and changes slightly with changes in flow rate in the discharge pipeline.
(106) The data from TABLE 2 is obtained as a result of simulation of the turbulent motion of flow medium in the flow domain of the given sizes and configuration; the optimal frequencies are computed, for which the hydrodynamic resistance coefficient reaches the minimum value for any value of the flow rate belonging to entire practical range.
(107) The main measured parameter is the flow rate,
(108) Simulating the turbulent motion of the flow medium under the action of pressure waves in the flow domain with specific configuration, sizes, and the experimental testing and specifying the obtained results, represent the methodological steps of practical realization of the proposed method. The dimensions of the flow domain are arbitrary. They do not impose any restrictions on the proposed invention.
(109) The obtained results are scalable and can be generalized to pumping and wave systems of other sizes and powers using hydrodynamic, energy, and geometric similarity criteria. Usually, sizes of the flow domain are chosen in a practical range of pipe diameters 6,
(110) TABLE-US-00002 TABLE 2 Baseline data. Pressure waves action. j
(111) The main results of the simulation are the computed optimal values of frequencies and amplitudes of pressure waves, providing minimum value of the hydrodynamic resistance coefficient for any value of the flow velocity, belonging to the entire practical range. They are generalized to all fluid media with the same, or very close physical properties: density, dynamic viscosity, compressibility. Therefore, when using dynamic controllers in industrial pumping stations to provide an energy efficient mode of the process of pipeline transporting of fluid media with the above-mentioned physical parameters, these results are uploaded directly into the memory of the dynamic controllers. And intrinsic parameters of the pumping and wave systems are generated during their operation, then are added in the baseline file during the compiling. They can be taken as estimated reference data for calculation of the energy efficiency of real pipeline transporting process.
(112) Therefore, main results can be used for pipelines of any configuration. Wherein, if the initial wave amplitude is not optimal, it can be non-essential corrected by the opening angle ? of the control valve 13, to provide the energy efficient mode. The program used for the automatic controlling in real-time of the energy efficient mode of the process of pipeline transporting of fluid medium, provides a continuously optimal value of the control function, by processing the feedback data of the dynamic state of the controlled system, which is determined by the flow velocity. The control function is maintained in the optimal mode,
(113) In the process of automatic control of the energy efficient mode, only a part of the measured parameters is used, presented in Table 2 and
(114) In the engineering system for pipeline transportation of fluid medium,
(115) Pump operation mode is carried out by a dynamic controller 17. For example, a constant speed of the pump impeller or a constant current in the pump motor.
(116) The PWG motor 9 is turned on and the pressure waves generator 8 starts to work, generating pressure waves. Speed of the motor is set to default which, usually, may not be optimal. The generated compression pressure wave propagates from the PWG through the connecting pipe 12 in the suction pipeline 5,
(117) Measurement devices 25-32 are measuring instantaneous values of the: speed of the pump motor, by tachometer 25; current of the pump motor, by amperemeter 26; speed of the PWG motor, by tachometer 27; pressure on the inlet of the suction pipeline, by pressure meter 28; flow rate of the fluid medium through the pumping system, by flowmeter 29; discharge pressure on the beginning of the discharge pipeline, by pressure meter 30; temperature of the fluid medium, by thermometer 31; current of the motor of the PWG, by amperemeter 32.
(118) Speed of the pump motor and of the PWG motor can be calculated by the standard voltage supplied to each motor and the measured current.
(119) Values of measured parameters are determined by the internal dynamic state of the turbulent flow. Weak changes in the values of the turbulent flow parameters, the trend, occur in the vicinity of the average value of the measured quantity, for example, of the flow rate,
(120) Note. Below we propose one of the schemes of the computational process to ensure an energy efficient mode, using the averaging time interval [m ?t]. However, for this purpose, one can use the other averaging time intervals that are multiples of [m ?t], for example, several averaging time intervals [m?t]. In addition, during the computational process you can use data from any cell of the last recorded row of average values of measured parameters in the file of average parameters, regardless of the number of averaging time intervals used.
(121) Let us consider, how the automatic control of an energy-efficient mode of the process of transporting a flow medium during the transition of the flow from one stationary state to another stationary state, with an insignificant change in the flow rate is performed.
(122) Further, in the text all average measured parameters are accompanied by the subscript wx.
(123) Let us assume that the process of pipeline transporting of fluid medium is carried out in the optimal mode. At the same time, the current values of the average parameters correspond to the last updated row (M?1) in the file of average parameters:
(124) In the file of average parameters, after an averaging time interval [m?t], the following set of average parameter values is recorded, in accordance with the row M:
(125) The search for the control function,
(126) Let the measured average value of the flow rate be
(127)
(128) Comparison of the remainder r.sub.M and choice of the control function.
(129) Let us assume that [p.sub.M]=j. Then, depending on the value of r.sub.M, for any j, the average value of the flow rate
1. r.sub.M?0.5 and |
2. 0.5?r.sub.M<1 and
3. 0.5?r.sub.M<1 and
(130) Conditions similar to (14) are satisfied by the average values of the measured current in the pump motor, current in the motor of pressure waves generator, and of the calculated energy efficiency. They are obtained by replacing the average flow rate in (14) with the average current in the pump motor, T.sub.WXM, the average current in the motor of the pressure waves generator, T.sub.PWXM, which determines the frequency of the generated pressure waves,
(131) The average values of the current of the pump motor, T.sub.PW and of the energy efficiency, ?.sub.fW directly depend on the average value of the flow rate,
(132) Practical execution of all steps in a logical sequence, which implementing a method of automatically controlling of energy efficient mode of the process of pipeline transporting of fluid medium, with any changes in flow rate, is described in detail below, flowchart of which is presented in
(133) The word parameters used in the blocks in
(134) The software implementation of the process of automatic control of energy efficient mode is shortly described below.
(135) Let us consider, how the automatic control of the energy efficient mode of the process of transporting a flow medium during the transition from one stationary state to another stationary state, with an insignificant change in the flow rate is performed.
(136) Let us use equality (13).
(137) 1. If r.sub.M=0, then p.sub.M=[p.sub.M], the program automatically assigns to the subscript j the value j=[p.sub.M], activates the row, j=[p.sub.M] from the baseline file for the turbulent motion of the fluid medium in a discharge pipeline, interacting with pressure waves. When
|
|?.sub.fWPXM?(?.sub.fW[PM].sup.in|<?.sub.EX,(16) ?.sub.EX is the maximum permissible value of the difference of the energy efficiencies. Physical conditions (15) provide practical conditions (16). The control of fulfillment conditions of the energy efficient mode, is performed by last block of the flowchart in
(138) If
(139) 1.1. If 0<r.sub.M?0.5, and
(140) The state of the controlled system with the flow rate
(141) 2. If 0.5<r.sub.M<1, and the average current value of the flow rate satisfies the inequality,
(142) 3. If 0.5<r.sub.M<1, and the average current value of the flow rate satisfies the inequality,
(143) Such insignificant adjustment of the values of control function between the average value
(144) Similar relationships are obtained for average values of flow velocities, when replacing the flow rate
(145) Let us assume, that the current values of the flow rate in the discharge pipeline equal to
(146) Assume, that the first measured value of the transient flow rate is
(147)
(148) If r.sub.A+1=0, then p.sub.A+1=[p.sub.A+1], and the subscript j is assigned a value [p.sub.A+1]: j=[p.sub.A+1].
(149) If 0?r.sub.A+1?0.5 and
(150) The program automatically activates the row j=[p.sub.A+1] from the baseline file, and performs sequentially the following steps: 1. transmitting value of the current T.sub.W[pA+1] from the corresponding cell to the output module 19; 2. transmitting value of the current T.sub.W[pA+1] from the output module 19 to the output-controlled device 20; 3. re-setting the optimal value of the current of the PWG motor 9; 4. providing the generating pressure waves of optimal frequency,
(151) Detailed of performing steps 1-8 is described above.
(152) If 0.5?r.sub.A+1<1, and the average current value of the flow rate satisfies the inequality,
(153) If 0.5<r.sub.A+1<1, and the average current value of the flow rate satisfies the inequality,
(154) Similar computational steps are performed automatically by the program for the entire set of transitional values of flow rate: {
(155) Providing the energy efficient mode is performed using a program, that analyzes, compares, computes, and continuously adjusts the value of the control function, ?.sub.opt, to the current state of the controlled system.
(156) To compare the energy efficiency of the action of pressure waves on the process of pipeline transporting of fluid medium, formula (1) is used. Comparative results calculated using the intrinsic parameters of the pumping system (the action of the constant pressure on a turbulent flow) and of the intrinsic parameters of the pumping and wave systems (the action of pressure waves on a turbulent flow), presented in the TABLE 2.
(157) Thus, in the proposed engineering system, the method of automatic controlling of the energy efficient mode of the process of pipeline transporting of fluid medium is provided in real time in both, stationary and non-stationary turbulent flows. In other words, the proposed energy efficient mode provides in real-time the optimal value of the control function for both the stationary state of the controlled system and for any transient states.
(158) The proposed engineering system for pipeline transportation of fluid medium and method of automatic controlling of the energy efficient mode can be successfully used for pipeline transportation of technological media, brines, different heterogeneous media, whose solid particles are sedimented on the inner surface of a pipe, and form a solid phase layer. The formation of such a layer leads to the decrease in the cross-sectional area of the flow, an increase in power of the pump motor, and a decrease in flow rate. The energy costs of operating such pipelines become economically unprofitable.
(159) The use of the system of generating pressure waves 15 in relation to the transportation of such media has the following advantage: reducing the rate of sedimentation of solid particles on the inner surface of the pipe, due to longitudinal sign alternating acceleration of the elementary fluid particles in the field of the pressure wave; increasing the life of pipeline.
(160) Prevention of decrease in sedimentation of solid particles is ensured not only by the frequency of pressure waves, but also by their form and amplitude. Even a small increase in the service life of pipes in industrial conditions is very important from economic standpoint. For example, in salt production factories, certain technological processes are accompanied by pumping brines at a temperature of 203? F. After about six months of operation, the cross-sectional area of the flow in this pipeline is significantly reduced. The specific energy consumption is increased and pipeline operation becomes unprofitable. These pipes are replaced with new ones.
(161) A baseline file similar to the one described in the method is used in control systems for certain industries. For control systems in such industries, the baseline file is similar to the one presented in the described method. A separate column in the baseline file must be added, to visualize the dynamics of specific energy consumption on a daily or even hourly basis. As soon as this parameter reaches the upper limit, determined by the energy efficiency, the dynamic controller sends an alert signal to the operator. The pumping system can be stopped automatically or by the operator.
(162) The modern filtration systems, for example, wastewater filtration systems, are operating only under the action of the constant pressure. The main problem in the modern wastewater filtration technology is the relatively quick filter clogging and filter cake forming. Consequently, the filter hydrodynamic resistance is increased. The pump power, and specific energy consumption to maintain the same flow rate, are also increased. Frequent filters replacements are relatively expensive. Therefore, at least a slight extension of the filter life, with acceptable energy efficiency, is economically profitable.
(163) The proposed engineering system and method of automatic controlling of the energy efficient mode can be successfully used in the wastewater filtration technology. In such case, in engineering system
(164) Longitudinal sign-alternative wave action on the filter cake, maintains it in unstable, loosened state; the state with more porosity. This state increases the performance of the filter and filtration efficiency. In addition, periodical action of pressure to the impurities within the filter itself, prevents their coagulation and settling on the pore walls, or solid filter particles, i.e., slowing down the filter clogging. Both these pressure wave actions lead to an increase in the life of the filter.
(165) For some filtration systems the PWG can be connected parallel to the filter.
(166) For filtration processes, the wave system 7 must generate pressure waves of such form and amplitude as to minimize the hydrodynamic resistance of the current state of the controlled system, new filter, and the filter cake. The optimal form, amplitude, and frequency of pressure waves for a given filter material and types of wastewater impurities is determined as a result of modeling and further experimental correction. This data forms the basis of the baseline file. Essentially, it is a table function ?.sub.opt fj(?, P.sup.?(t),
(167) It will be understood that the proposed engineering system with such dynamic controller, with an installed program and baseline file of technological parameters of the microprocessor and memory is provided by way of example but not limitation, and embodiment of the present invention can be used in engineering systems for pipeline transporting of fluid media with more complicated properties, and in other technological processes with changeable parameters, for the purpose of automatic controlling of energy efficient mode. Moreover, the control function does not necessarily have to be of the optimal value of frequency of generated pressure waves. For some technological applications, the form of pressure wave or amplitude may be optimal. Ultimately, the amplitude-frequency characteristics of the wave are important. It is the dynamics of pressure changes in the wave that determines the energy efficiency of the wave's impact on the controlled system. Performing such action on the controlled systems by pressure waves of various forms and amplitudes is ensured by the frequency of the generated waves, which are automatically controlled by the speed of pressure waves generator.