PROPULSION CONCEPT COMBINING CONVENTIONAL ROCKET ENGINES AND AIR-BREATHING ENGINES (HEBER CONCEPT)
20220243684 · 2022-08-04
Inventors
Cpc classification
B64G1/401
PERFORMING OPERATIONS; TRANSPORTING
F02K7/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F02K7/18
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
A system for vertical or inclined take-offs of air-breathing engine systems comprising: an additional guidance system for the air-breathing engine system, which can selectively supply additional inflowing atmosphere or air. A control system capable of selectively supplying the additional incoming atmosphere in a variable manner to the air-breathing engine system. Additional inflowing atmosphere air can be supplied by thrust, from a conventional rocket engine system or the air-breathing engine system. Volumetric base structure pneumatic or hydraulic press-on body and flexible deck structure as variable or partially variable in shape or position for air-breathing thruster system, guidance system, control system. Variable diffusers, bypasses, exhausters, open spaces, junctions of mass flows of the additional incoming atmosphere at the additional guidance system or in the engine to specifically prevent scavenging or stalls. Additional mobile feed of an oxidizer carried along for starting purposes or for support during operation.
Claims
1. A system for vertical or inclined take-offs of air-breathing engine systems comprising: an additional guidance system for the air-breathing engine system, which can selectively supply additional inflowing atmosphere or air.
2. An apparatus according to claim 1 comprising: A control system capable of selectively supplying the additional incoming atmosphere in a variable manner to the air-breathing engine system.
3. A method according to claim 1 or 2 wherein the additional inflowing atmosphere, or air for at least one air-breathing engine system can be supplied by thrust, from at least one of: a conventional rocket engine system, an air-breathing engine system.
4. A method according to claim 1 or 3 wherein the additional incoming atmosphere, or air, is supplied by the thrust of the air-breathing engine system for at least one air-breathing engine system via the control system under the control of the control system.
5. A method according to claim 1 or 2 wherein a bypass or stall of the additional incoming atmosphere or air at the air-breathing engine system is specifically prevented by the control system and varied by the control system.
6. A guidance system according to claim 1 comprising: At least one of the following: Culverts, bypasses, exhaust devices, open spaces, mass flow nodes.
7. A guidance system according to claim 1 consisting of: at least temporarily and at least technically in part, at least one of the following: flexible textiles, nets, ropes.
8. A method according to claim 1 In which the air-breathing engine system is operated at least in part for launch purposes or to assist in operation with additional movable injection systems of an entrained oxidizer.
9. A system according to claim 1 comprising: At least one of the following systems in a separable embodiment: air-breathing engine system, guidance system, control system.
10. A system comprising: Volumetric base structure pneumatic or hydraulic press-on body and flexible deck structure as variable or partially variable in shape or position in at least one of the following systems: air-breathing thruster system, guidance system, control system.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
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DETAILED DESCRIPTION
[0128] The inventor provides a system for using the atmosphere as an oxidizer in the vertical launch of rockets.
[0129]
[0130] Ramjet engines can be designed for face velocities from at least Mach 0.75 to over Mach 5. In particular, however, individual engines are only optimized for a specific range. In the following, performance values are given for both subsonic and supersonic ramjets, each with subsonic combustion chambers according to the state of the art (100). In each case, hydrocarbons such as kerosene are used as the fuel. To ease the burden, the parameters are shown both with figures and with identical textual descriptions.
[0131] Historically sorted are the power values from representative sources of several decades. Data from [8] are from 1978 and are shown as (111). Values from [2] published in 1997 are shown as (120) for the minimum and (121) for the maximum. Data from [7] published in 2011 are described as (130) for the minimum and (131) for the maximum. Data from [9] published in 2021 are recorded as (140) for the minimum and (141) for the maximum. Compared with (111) from 1978, the performance values are in some cases greatly increased and only fall short of (140) in some cases for minimum performance values of newer engines. (111), however, falls significantly short of the values of (141). A comparison of newer sources does not reveal any clear trend toward increased performance. The power values generally show a typical maximum value in the medium speed field at around Mach 3 and decrease again with increasing approach speed.
[0132]
[0133] The large difference between minima and maxima shows further potential for optimization.
[0134]
[0135] Since the density of air tends to decrease with increasing altitude, increasingly higher speeds are required at higher altitudes in order to be able to supply air-breathing engines with the necessary oxidizer. Progressive developments are extending the limits of use.
[0136] The diagram does not generally distinguish between turbine engines, subsonic ramjets, ramjets or scramjets. The overall range of the respective operational limits is covered. (211) represents the lower limit of deployability and (212) represents the upper limit of deployability. By (213), the typical minimum speed of ramjets is shown to be about Mach 1.5. Below that, the use of subsonic engines or ramjets with launch aids, or e.g. the additional feeding by carried oxidizer, is possible. At (214), an upper speed limit for ramjets with hydrocarbons of about Mach 5 is given. In addition, operation of dual-mode Ramjets with switching to supersonic combustion is possible. The use of scramjets with only supersonic combustion is an alternative. Speed limits vary in the literature depending on publication date and fuel.
[0137] (221) shows the characteristic curve of the “Ram Booster” concept of the National Aeronautics and Space Administration (NASA) with the intended use of a ramjet as second stage (of 3 stages). Upstream, the operation of 18 turbine engines in the first stage and downstream, the operation of a rocket engine in the third stage is conceived. This is intended to utilize the largest possible specific pulse. (222) shows part of the characteristic curve of the lower stage of a Falcon 9, which is still operated up to approx. 84 km or 276,000 ft.
[0138] From the plot, it is clear that with the typical speed profile of a Falcon 9, effective operation of a typical ramjet would not be possible, since the allowable operational limits are almost entirely outside the intersection of (213) and (222). Also, with (212) and (214), a limit of operation of a ramjet up to an altitude of at most about 100,000 ft altitude is still technically possible.
[0139] Additional measures are therefore required to accelerate a reusable lower stage by means of air-breathing engine systems. One possible measure is to increase the thrust-to-mass ratio of the rocket in order to accelerate more strongly in the denser air layers and to be able to use the atmospheric oxygen earlier and more intensively. Another measure is to increase the inflow to the air-breathing engine systems in order to partially increase the inflow velocity at the engine inlet (Heber Concept). According to
[0140] The required operation of air-breathing engine systems over the maximum possible speed range or at large altitude differences is a challenge.
[0141]
[0142] On the horizontal axis, the time is shown in [s] (301). On the vertical axis, the velocity is shown in [Mach] (302). The course of the velocity increases with increasing time. This is due to the decreasing weight of the rocket (fuel combustion). With (310) the typical velocity curve is shown approximately. After approx. 162 s, the stage separation of the lower stage occurs at approx. Mach 6.7.
[0143] The diagram in
[0144] Possible measures are: [0145] increasing the thrust-to-mass ratio for greater acceleration in line with the increased acceleration at burnout of lower stages (e.g., on a Falcon 9), [0146] additional injection of an oxidizer in air-breathing engine systems (e.g.
[0150] Subsonic ramjets sometimes achieve specific pulses two to three times that of classical rocket engines. Ramjets can convert with hydrocarbons according to [1] even at a maximum of approx. 2,000 s at approx. Mach 2-3. This corresponds to about five times the specific pulse of conventional rocket engines. However, this peak value is only reached in a narrow design range in each case. A higher specific pulse means that less propellant has to be carried and accelerated. The possible mass shift can be used to increase the payload fraction.
[0151]
[0152] The air mass flow (30) enters the engine duct (1001). The flow (30) is decelerated in the diffuser or inlet (1002). The subsonic ramjet, or Lorin jet pipe, introduces the air mass flow (30) with a low compression ratio. Fuel (8) is added in the mixing section (1003) via the injection (11). In the combustion chamber (1004), combustion (25) takes place in the area of the igniters or flame holders (20) with the highest possible burnout of air mass flow (30) and fuel (8). There are various forms and arrangements of igniters, or flame holders (20), some of which are multi-row. Development is not complete and, according to [9], is one of the main factors influencing optimum burnout. Combustion (25) can thus take place supported on calmed flow zones on flame holders (20). Alternatively, contactless ignition, e.g. via electromagnetic waves, is possible. Downstream of the combustion chamber (1004), the nozzle (1005) optimally converts the thermal energy of the combustion into usable thrust. A converging-diverging nozzle shape (1005) is shown.
[0153] For subsonic ramjets, a maximum speed of simplified about Mach 2 is considered. In addition, the increasing combustion chamber pressure (thermal backpressure) typically “blocks” the inlet (1002). The resulting scavenging of the engine duct (1001) makes the engine increasingly ineffective. Beyond Mach 2, a higher compression ratio is required (
[0154]
[0155]
[0156] In the embodiment shown, the intermediate body (22) has a downstream pointed contour (24).
[0157] Compared with
[0158] According to [1], this involves additional complexity. Friction during the mixing of different fluids in the mixing area (1003) results in higher thermal stress on the combustion chamber (1004) and additional detrimental energy conversions.
[0159]
[0160] According to
[0161] The following variables are used to control air-breathing engine systems (2) at different pressures: [0162] Freights of additionally injected oxidizer (811), [0163] effective area of additional inflow (821), [0164] injection of fuel into combustion chamber (831), [0165] adjustment of compressor ratios (841), [0166] flow cross-section in the thrust nozzle (851).
[0167] If necessary, further control variables such as variable geometries of the inlet and other areas, boundary layer suction, air outlet flaps, air inlet flaps, control of surfaces can be additionally adapted. With the control of loads of additionally fed catalysts and the adaptation of the ignition by electromagnetic waves (e.g. microwaves) further control methods are available. See the patent applications of the same applicant (DE 10 2021 000 701.8 and DE 10 2021 001 272.0). Ideal are the flexibilized geometries and the adaptive engine concept (patent application DE 10 2021 004 784.2 from the same applicant), respectively, e.g.
[0168] The influencing variables are grouped for a highly simplified and rough control program, ordered by tendency of pressure/velocity (801) and density/height (802). The sizes of the gradients are freely chosen for illustration and depend on inner and outer boundary conditions for permissible values of the sizes. By superimposing the course of velocity (801) and height (802), the effects can be partially cancelled.
[0169] With increasing velocity (801) of the inflow, the pressure in the inlet increases, which, according to the Carnot process, increases the internal area and thus the work of the cyclic process. This tendency is superimposed by the strongly decreasing density of the air with increasing height (802) during a vertical start.
[0170] According to [1], the compressor or inlet pressure ratio is optimized together with turbine inlet temperature and Mach number. The ratio of outlet to inlet pressure can be adjusted by the geometry of the inlet. The higher the temperature, the higher the optimum compressor pressure ratio. This also increases the M-number for the maximum thrust. These adjustments are particularly necessary for supersonic engines. In principle, however, the temperature can also be adjusted by using catalytic combustion (see patent application DE 10 2021 000 701.8).
[0171]
[0172] The intermediate body (22) shown is typical for higher incident flow velocities of an air mass flow (30) that is as coaxial as possible. The intermediate body (22) projects well beyond the leading edge of the remaining engine duct (91).
[0173] A characteristic feature of this inlet shape, or a uniformly downstream axially symmetrical engine duct, is the sophisticated controllability of the flow geometry. The most uniform and homogeneous flow situations possible in the engine are essential for control.
[0174] For illustration purposes, a cross-section with I-I is shown. (92) shows a bead that can be pressed on (e.g. made of metal/ceramic fibers). This can be mechanically expanded and retracted, e.g. by means of hydraulics. Due to transverse elasticity and deformability, the annular gap (93) is uniformly gripped and delimited. The flow, or air mass flow (30) in the annular gap (93) can thus be uniformly influenced. On the inside of the annular gap (93), actuators (94) are indicated. However, this intimation with alternating pattern of black and white is to represent the complexity required for such kinematics. The requirement for thermal (thermal expansion), material (impurities, adhesions) and mechanical stresses on the flow would be enormous. It is therefore essential that the intermediate body (80) can be moved along the flow axis.
[0175] The degrees of freedom of the control with concentric inlet are limited and the requirements are high. This form of control is not claimed by this patent application.
[0176]
[0177] Plane bodies are more freely movable in plane structures. Resulting degrees of freedom of the controls are shown by the numerous motion arrows (1050), (1051), (1052), (1053), (1054). For simplicity, the degrees of freedom are designated uniformly. Movements with respect to the inlet plane are summarized by (1051). Movements affecting rotations or circumferential movements, e.g., in flaps (1066), are essential with (1052). Movements perpendicular to the flow are summarized with (1053). Movements in flow direction are shown with (1054).
[0178] In the embodiment
[0179] A flap (1063) is arranged at the leading edge to allow suction (1064). In addition, a gate valve (1065) is shown for increased control of the bypass, or engine duct (1001). Flaps (1066) are arranged in the engine flow (1001), which can divide, or shift, the incoming air mass flow (30). Two flaps (1066) in the engine stream (1001) have the ability to rotate (1052). Another flap (1068) has the capability of longitudinal displacement (1054) and transverse displacement (1053) in the engine flow (1001). The aim is to variably increase the compression in the inlet of the engine stream (1001).
[0180] The choice of flaps is such that an intermediate body as in
[0181] Therefore, to enable more controllable systems, planar shapes according to
[0182] The embodiment of
[0183] Fed air-breathing engine systems can be used to increase performance: [0184] for self-starting and with highly variable conditions [0185] for the combination of exclusively air-breathing engine systems with fed-air-breathing engine systems and distribution of the incident flow, e.g. via a control system that can be modified via a control system [0186] in addition, with exclusive supply also outside denser atmospheres
[0187] During startup, the additional injection of an oxidizer is required due to the lack of incident flow of the air mass flow (30). In this embodiment, additional injection systems (16 and 26) are provided. These inject over a large cross section along the air mass flow (30). The mixture (21) is injected via the fixed injection (16) at the intermediate body (22) in the head of the combustion chamber (1004) and the movable injection (26). Movable lances (26) with devices for injection are extended in the area of the engine duct (1001). Ideally, the lances (26) are rotatably mounted on the side walls (1101). However, in order to relieve the mechanical system, simple displaceability (translation) is also possible. The lances (26) are inserted at an angle into the engine duct (1001) to cause as little flow resistance as possible and to prevent jamming during backward movement. The lances (26) are designed in such a way that they counteract the incident flow or the combustion chamber pressure with a higher area moment of inertia. This means that the cross-section of the lances (26) is longer than wide, the length being aligned with the longitudinal axis (1001) of the engine. The lances (26) also have a flow-favorable, e.g. teardrop-shaped, cross section. The lances (26) can be mounted on the outside of the engine or on the side walls (1101), or on the inside of the intermediate body (22). In the embodiment shown, the lances (26) are mounted externally on the fixed side walls. The lances (26) are moved by means of a hydraulic system; alternatively, cushions or electric motors/actuators with corresponding power are also possible. At the same time, fuel is injected via the injection (16 and 26) in a mixture (21). Nozzles are arranged at several points on the lances (26). Multi-directional nozzles are preferably used for this purpose. The atomized mixture (21) is ignited in the combustion chamber (1004).
[0188] The additional injection of oxidizer in the mixture (21) is adapted to the air mass flow (30), or reduced if necessary. As the speed of the air mass flow (30) increases, more oxidizer flows into the combustion chamber (1004). The adjusting device with the movable lances (26) is retracted, or retracted. No major internals of the self-starting aid, or of the additional injection systems (16 and 26), remain in the engine duct (1001) when the engine is shut down. The additional injection systems (16 and 26) are deactivated in the preferred embodiment. However, the additional injection systems (16 and 26) can optionally continue to be operated to increase power, or can be put into operation again. The fuel (8) is otherwise injected via the control injection (11) and mixed with the air mass flow (30) in the mixing chamber (1003). If necessary, it is switched to injection of the fuel (8) via the control injection (11).
[0189] The inlet is designated by (1002) and the nozzle is designated by (1005).
[0190]
[0191] When the rocket (0), or the missile, is launched from the ground, 2 laterally arranged inflow flaps (3) are extended in the maximum position for the largest possible inflow area perpendicular to the velocity vector via the control system (4). The inflow area is extended and, if necessary, retracted again depending on flight time, speed and altitude/atmospheric density.
[0192] This results in an inverted “arrow” in the direction of flight, the arrowheads of which tilt and, if necessary, open again. In the case of two opposing leading edge flaps, the mechanics of the system can be simplified, e.g. by mutual bracing of the leading edge flaps. These geometries are already state of the art in a similar form for auxiliary power units on commercial aircraft (e.g. for increased thrust)—see e.g. patent specifications US 2010/0044504 A1, U.S. Pat. No. 9,254,925 B2, US 2019/0390601 A1.
[0193] In
[0194] The conventional rocket engine system (1) launches the missile for a predominantly vertical trajectory in order to achieve a takeoff speed; if necessary, the air-breathing engine systems (2) are fed with oxidizer by self-launch aid. During regular operation, the airflow (30) is sufficiently compressed, or accelerated by the speed and thrust of the rocket, or fed in compressed form into the air-breathing engine system (2). The novel guidance system (3) can be used to increase the required compression/flow rate of the atmosphere or air (30) with additional inflow. Optionally, the air-breathing engine systems (2) are designed to be adaptive or adjustable to cover a wider range of applications (patent application DE 10 2021 004 784.2 from the same applicant). Atmospheric oxygen (30) is utilized and the entrainment/acceleration of an encapsulated oxidizer can be reduced. The control system (4) can adjust the incident flow area of the guidance system (3) to speed and altitude/or atmospheric density. At higher altitudes with thinner atmosphere or air (30), the incident flow area of the guidance system (30) can be increased again. The guidance system (3) and control system (4) thus provide for a larger operating range of the air-breathing engine system (2) at lower speeds of the rocket (0) and also at greater altitudes. The flow of the air mass flow (30) is adapted to the speed of the flying object.
[0195] The aim is to integrate the air-breathing engine system (2) at an early stage into a variable aerodynamic system with the aid of a guidance system (3) and control system (4). Via the control system (3), additional incoming atmosphere or air (30) is guided as completely as possible to the air-breathing engine system (2). After the air-breathing engine system (2) has been launched/operated, the conventional rocket engine system (1) can be separated from the missile as a “sub-stage”. In this way, the percentage of expendable payload can be further increased. Optionally, the oxidizer to be carried can be minimized. Alternatively, the conventional rocket engine system (1) can continue to operate, be decommissioned and restarted for higher altitudes, or orbits. The air-breathing engine system (2), guidance system (3) and control system (4) can be separated before reaching the target orbit and the missile can continue to be operated with one or more conventional upper stages. The control system (3) and guidance system (4) prevents stalls on the air-breathing engine system (2).
[0196]
[0197] This design variant is technically approximated in simplified form in
[0198] The body of the manta ray (1300) with the large fins (1305) has a broad mouth (1302) at the front part with head fins (1303) in front. The animal is propelled by constant movements of the fins (1305). Water and biomass flows into the mouth (1302) as a mass flow (1304) with plankton and small creatures and is discharged again via flaps/gills.
[0199] Eyes (1301) are shown for better illustration.
[0200]
[0201] In this embodiment, a guidance system (3) is arranged along the rocket (0). The axial guidance system (3) discharges at a control system (4) of movable inflow flaps. The air-breathing thruster system (2) detects the aerodynamic flow around the rocket (0) with the incoming air mass flow (30). For improved controllability, the air-breathing engine systems (2) in this embodiment are shown with a planar inlet. At the same time, a targeted additional inflow is effected via the additional inflow surface (3). In this variant, air-breathing engine systems (2) are arranged directly on a lower stage of a rocket (0). Alternatively, an arrangement on separate auxiliary engines or boosters is also possible.
[0202] After leaving the denser air layers, the air-breathing engine system (2) is disconnected or continues to operate via an additional feed of an oxidizer. The air-breathing thruster system (2) can be disconnected from the upper stage, or payload. The payload continues to move.
[0203]
[0204] Alternatively, or in further development, supplementary parachute systems, or chutes, nets made of fibers or textile guidance systems can be used to increase the inflow, which can be used up to a maximum speed, or wing load. After the surface load has been exceeded, it can then be selectively separated or retracted, if necessary. These systems can also be combined with other approach flaps. The favorable ratio of mass to maximum area is particularly advantageous in the takeoff phase in order to achieve speed quickly.
[0205]
[0206] A free air mass flow (30) can be developed between the guidance system (3) as a bypass. In order to prevent the guide system (3) from being bypassed, the guide system includes a passage device (5).
[0207] For a favorable ratio of structural mass to payload, the three-part guidance system (3) is countered on cables which can be shaped as flat cables. This allows a more targeted inflow (30) to the air-breathing engine systems (2). At the same time, this reduces stalls or undesirable flow around the engine and allows more targeted control (4) of the guidance system (3).
[0208] Alternatively, flexible nets or further flat cables on the sides of the split guide system (3) are also possible to prevent air mass flow (30) from flowing off. Thus, a higher air mass flow (30) can be supplied to the air-breathing engine system (2).
[0209]
[0210] The illustration of
[0211] Objectives here can be: [0212] Limitation in case of unstable compressor work [0213] Limitation of mechanical loads, [0214] limitation of thermal loads [0215] Limitation of unstable combustion
[0216] With Mach number enlargement, the compression in the inlet can be increased, if necessary. The Mach number increase leads to higher compression of the inlet air mass flow (30). With higher Mach number, the geometry of the critical area of the nozzle can be enlarged. This leads to thermal and mechanical relief of the combustion chamber or adaptation in the engine duct (1001).
[0217] The figure is divided into a flow section in front of the flap (1701), the area of the flap (1702) with the flap and adjustment devices, and the flow section behind the flap (1703). The cross-sectional area behind the flap (1703) is widened to represent as large a control area as possible. This results in a delay of the flow for incompressible media.
[0218] With a reduced cross-section, the air mass flow (30) is accelerated to a permissible maximum value (1704). The maximum value (1704) is derived from the permissible mechanical and thermal loads on the flap (1702) and the remaining engine duct (1001). Depending on the engine duct (1001) downstream, the air mass flow (30) can, if necessary, expand again and take up the original cross-sectional area with losses. In an assumed neutral position (1705), there is no decisive change in the air mass flow (30). In the minimum position (1707) of the damper (1702), a maximum deceleration of the air mass flow (30) can also be aimed at if necessary.
[0219] In summary, flaps (1702) are basically and versatile for the mechanical control of engines, possible especially with flat contours. However, the use of flaps (1702) results in disadvantages and technical limitations. For example, moving parts are always a source of faults and susceptible to failure in terms of the stressed mechanics and seals. In addition, dampers (1702) are costly and have complex interdependencies. In addition, the effectiveness of flaps (1702) may be limited, as illustrated by
[0220] In this respect, in comparison, a continuing trend in the creation of engineering structures is, for example, the use of fibers/nets/textiles made of steel, carbon and plastics, respectively. Possibly, based on progressive development, this holds further serious potential for aerospace regulation.
[0221]
[0222] Compared with
[0223]
[0224] Various flaps are shown which can form an intermediate body (1826) when adjusted accordingly. For this purpose, the flaps (1821, 1822, 1825) are shown retracted in order to limit the flow resistance in the retracted state, e.g. at low inflow velocity of the air mass flow (30). A deflector (1820) is provided in front of the flaps (1821) to prevent turbulence, thermal/mechanical loads and flow through. This is as close as possible to a subsonic ramjet as shown in
[0225] At higher inflow velocities of the air mass flow (30), the forward flaps (1821) swing open and are fixed by holding torques, actuating mechanisms, etc. The middle flaps (1822) are then extended to the maximum position. These flaps (1822) are shaped in such a way that they have an adapted and angled upwind side in order to map the intermediate body in the best possible way. The end flap (1825) prevents flow around or unstable conditions, e.g. at higher combustion chamber pressures. For relief against combustion chamber pressures, the end flap (1825) is notched for a retaining rod or retaining points (1824). Simplified, a minimum and a maximum position is possible with this shape.
[0226]
[0227] By narrowing the total cross-section to a minimum (1911), for example, the initially low and slow air mass flow (30) can be converted at increased speed in the flexible engine duct (1901). At higher speeds, maximizing the engine cross-section (1912) is advantageous, e.g. to relieve the inlet.
[0228] A separate enclosure or outer nacelle is possible, but not considered in this example. In accordance with
[0229] For simplification, the internals in the engine duct (1901) such as injection (11) for fuel (8), flame holder (20) for combustion (25) are designed as rigid. Alternatively, some of the internals can also be attached to the flexible combustion chamber wall.
[0230]
[0231] In this embodiment, a combination of mechanical components, such as hydraulic systems, bearings, etc., and possibly marginal flaps (2012) with a body is shown. The body (2015) can deform the volume/engine duct (1001). Ideally, it should be used with flat inlets, or engine ducts (1001). This principle is referred to below as a volumetric system. In this embodiment, in particular, a combination of mechanical-volumetric control is illustrated with an advantageous marginal design.
[0232] In the embodiment variant, mats (2015) made of fibers of a ductile metal (e.g. copper/nickel/steel) are shown. These mats (2015) can also be designed as a closed cushion, or bead. Alternatively, a design with other materials such as ceramic fibers is possible. The bending stiffness of the mat (2015) can be adjusted by layers of mats and mesh mats with different running directions. Furthermore, the mats (2015) can additionally be attached to movable retaining bars (e.g. on both sides of the mats).
[0233] The cross-section for the air mass flow (30) is narrowed by bending and pressure, or “squeezing” on presses/hydraulics (2014). At the side of the mat (2015), upstream, a flap (2012) and inclined cylinders (2013) are shown. Through this device, the shape and tension of the mat (2015) can be better adjusted and made uniform. To limit stresses, if necessary, can also be shifted in several sub-segments. For cooling, if necessary, expanded compressed air, or an attached cooling circuit can serve. Downstream with (2016) another hydraulic system is attached to regulate the tightness and shape also at different loads/temperatures. Upstream of the control system, there is a wall piece (2011) with an edge to fit the system optimally into the engine duct (1001). After the system, downstream, the thruster wall (2017) is also designed in an analogous manner to be connectable and rounded.
[0234] In order to achieve the highest possible load-bearing capacity with the best possible flexibility and the lowest possible weight, a composite structure consisting of a sealing layer, a force-conducting intermediate layer (e.g. meshes, honeycombs, rings) and, if necessary, a counter-layer is possible. Ring structures have been proven, for example, in historical chain mail as flexible protective clothing.
[0235] The surface of the mat (2015) can be designed to favor flow, e.g. with recesses, or small riblets, dimples. This arrangement has only a low flow resistance. However, the complexity of the design variant is very high.
[0236] For the sake of good order, intermediate body (1826), injection (11), for fuel (8), flame holder or igniter (20) for combustion (25) are shown.
[0237]
[0238] In contrast to
[0239] With appropriate cooling, or short use, it is also possible to use it in the combustion chamber area.
[0240] A sketched longitudinal section of a ramjet is included in
[0241] Analogous to the previous embodiments, a flat engine duct (2201) is shown. The side walls are fixed and arranged around the engine duct (2201). An outer nacelle (2210) is provided.
[0242] Compared to
[0243] In order to adapt the inlet (2202), mixing area (2203), combustion chamber (2204), nozzle (2205) accordingly in a flexible manner, a mat (2015), fiber-reinforced mesh, armored chains (chain mail), metal strips, etc. can be used, for example.
[0244] The mat (2015) has layers of finer fibers for sealing and thicker fibers for load transfer, or alternatively high-strength, fine and flexible fiber structures. The mat (2015) is force-fitted to rods (2211) on both sides or, as in this embodiment, the mat (2015) wraps around the retaining rods (2211). At the end, a special retaining rod (2212) can be moved along the longitudinal axis of the engine duct (2201) for retensioning. The rods (2211, 2212) are movably attached to the fixed side walls of the engine duct (2201).
[0245] In the embodiment, the intermediate body (2226) is also designed to be movable.
[0246] This arrangement enables optimum combustion (25) at the flame holders (20).
[0247] The relatively short time until burnout at an altitude of approx. max. 100,000 ft of max. 90 s has a relieving effect on the heat balance of the engine (2201). The thermal inertia of the material can also be utilized here. In addition, flexible hollow fibers can be flushed with cooling liquid, or e.g. compressed air can be expanded between outer nacelles (2210) and mat (2015).
[0248] The intermediate body (2226) is provided with a separate reinforced tensioning device (2221).
[0249] This form of control is according to the invention by movable mats and can be limited to individual areas. A mechanical solution with volumetric design potential is provided.
[0250]
[0251] Hardships and complications that usually speak against the use of comprehensive control in engine systems are mainly: [0252] the additional complexity, [0253] the additional weight, [0254] susceptibility to faults.
[0255] In this example, a simplified control system based on elements of inflatable, press-on cushions (ideally pneumatic) is presented. Such cushions can be designed to be powerful and resilient. A recent and concise application is the use of heavy-duty cushions in Austrian and German tunnel construction underground in a limited turning area. This was the case in the “Stuttgart 21” rail project. In 2020, up to approx. 1,000 t heavy segments of a powerful tunnel boring machine were moved underground in a so-called “Wendekaverne” (turning cavern) and reliably turned in a very small space. Sealing pads are also used in other engineering applications, e.g. for sewers.
[0256] The heavy-duty cushions (2302) allow an effective counterpressure to be built up against the flexible thruster duct (2301). This also allows the dissipation of stresses, bends, etc. Ideally, this eliminates the need for further retaining systems, rods, mating parts, etc. This reduces effort, weight and costs.
[0257] In principle, only an outer nacelle (2210) or supports, heavy-duty cushions (2302), composite structure if required, and a flexible cover layer (2303) are necessary. Cables and fibers in the flexible cover layer (2303) allow the transfer of tensile and shear forces in the tensioned state, or composite. Tension cables, for example, are used for long bridges in lightweight construction. Safety nets and meshes are used to protect against rockfall and avalanches.
[0258] The heavy-duty cushions (2302) in this example are used pneumatically. If necessary, a multilayer and parallel structure of the heavy-duty cushions can be selected.
[0259] A flexible cover layer (2323) with high post-tensioning is installed in the area of the flexible intermediate body (2326). This ensures that the intermediate body (2326) with the heavy-duty cushions (2322) contained therein is minimized for low inflow velocities of the air mass flow (30). Optionally, the heavy duty cushions (2302, 2322) are provided in single or multiple layers, or divided along the cross-section. The intermediate body (2326) can also be created polygonal, e.g. rhombic, in cross-section to approximate a highly effective annular combustion chamber.
[0260] For reasons of weight and performance, the heavy-duty cushions (2302, 2322) are actuated pneumatically, e.g. by compressed air, or by a flow of air (30). A hydraulic version is possible, e.g. by means of pumping liquids, possibly storable fuels (8) (e.g. kerosene). However, this is thermally more demanding, e.g., for longer operating times. In addition, if pneumatic cushions (2302, 2322) are used, they can be depressurized, e.g. via pressure relief valves, when the internal pressure increases due to heating. The relaxed working fluid has a cooling effect.
[0261] Alternatively, a combination of cushions (e.g. for the inlet) and mechanical systems, or fixed sections, is also possible (e.g. in the combustion chamber).
[0262]
[0263] Compared with the version shown in
[0264] Adaptive expansion of the engine cross section in the area of the combustion chamber (2404) can provide additional thermal relief for the inlet. Alternatively, a combination with an intermediate body may be advantageous for low inflow velocities. For example, for large air mass flows (30) with high density and low inflow velocity, this can contribute to sufficient combustion in a startup phase. To increase the thermodynamic efficiency of cyclic processes, high pressures are generally advantageous.
[0265] If necessary, combustion pressures can be increased by means of a Treiber Concept for catalytic combustion (patent applications DE 10 2021 000 701.8 and DE 10 2021 001 272.0). Contactless ignition via electromagnetic waves (e.g. microwaves) is also valuable for reducing pressure losses in the combustion chamber, as internals such as flame holders can be reduced (patent application DE 10 2021 001 272.0).
[0266]
[0267] The boundary layer can lead to an “energy loss”, i.e. energy transfer across the system boundary of the thruster (2501). In order to aim for positive limits, the boundary layer is extracted after the inlet in the area of flaps (2511). The exhaust is led into a bypass (2512). To avoid losses of fuel (8), the area of the suction (2511) is placed upstream of the area of influence of the fuel injection (11). Alternatively, it is also possible to exhaust further upstream or to discharge by further opening the flaps (2511). A feed (2513) is provided via the bypass (2512) into the area of the nozzle (2505). Here, an afterburning of the proportional air mass flow (30) exhausted with the boundary layer can be aimed at. Technically advantageous is also a cooling of the combustion chamber walls and at the incision of the nozzle (2505) during continuous operation, or to save effort. The kinematics in the nozzle (2505) can also be influenced. To increase this effect, the bypass (2512) can be widened in the meantime. This principle is not fundamentally new and is derived from earlier turbine engines or precursors of turbofan engines.
[0268] In addition, the geometric influencing of the boundary layer is carried out analogously to the acceleration of the boundary layers in wind tunnel test rigs (with projecting bodies in front of measuring areas) also by means of cross-sectional narrowing (2514). In cross-section I-I, the side walls (2515) are shown tapering in the gusset area (2514). Due to the cross-sectional constriction (2514), acceleration occurs in approximately incompressible media according to the continuity equation. The energetically decisive boundary layer is reduced.
[0269] For the sake of good order, it is also possible to influence the boundary layer at the micro level as an alternative to the above-mentioned possibilities at the macro level. Riblets (sharkskin) or e.g. dimples can be used for this purpose (see e.g. patent specification DE 696 20 185 T2).
[0270] In addition, the boundary layer can also be removed by suction at the side walls (2515). If movable mats are used, this is the preferred variant. A gap can also be opened up or regulated by means of cushions (2302). Technical simplifications are aimed at here.
[0271]
[0272] In
[0273] Nozzles with axially displaceable mushroom (2600) are considered, for example, in the patent specification US 2003 0154720 A1 for controllable Ramjets. This nozzle shape provides a relatively simple structure for control. The critical area (2604) can be increased or decreased by longitudinal displacement of the nozzle (2605). Relatively good characteristic values can be achieved with a relatively simple design. A disadvantage is generally the poor cooling of the central body.
[0274] Ejector nozzles with a rigid outer contour (2610) are common for early turbine engines. The gas flow (2611) flows inside the nozzle. The external ejector flow (2613) cools and is entrained by the gas flow under suction. The ejector flap (2612) has a partially self-regulating effect. This allows the critical area to be adjusted. Additional nozzles have been developed to improve the characteristic values (e.g. the thrust coefficient).
[0275] The ejector design with inner Laval nozzle (2630) has some additional elements. A Laval nozzle (2635) is installed for the inner gas flow (2634). For example, the outer aerodynamic flow can be improved with devices (2631). Dampers (2632) regulate the critical area, or distribution, of the outer ejector air flow (2632) and inner gas flow (2634).
[0276] Laval nozzles with two rows of segments (2640) represent another design. The two inner conical flow sections (2642) and (2643) consist of movable segments. By means of two surrounding belts of hydraulic cylinders (2641), different expansions or contractions can be exerted. This allows the critical area and the nozzle exit area to be continuously adjusted.
[0277] According to [10], the detachment zone in nozzles can be influenced, among other things, by adjusting the pressure of the combustion chamber. In patent application DE 10 2021 004 141.0, this is aimed at in terms of process, e.g. by using catalytic combustion (with variable loads).
[0278]
[0279] The ability to parallelize the operation of conventional engine systems of lower stage (2710) and boosters, or air-breathing engine systems (2721), means that the thrust of the various engines can be applied simultaneously, selectively and variably. In this way, for example, the variable inflow velocity, density and other parameters can be balanced in the best possible way. Other remaining parameters are e.g. temperature, viscosity etc.
[0280] The auxiliary power unit systems (2720) consist of 1 row of hinged leading edge flaps (2722). Alternatively, a design with more rows is also possible. As shown in
[0281] Alternatively, a combination of a flat inlet with a concentric combustor is also possible, as shown for example in patent specification U.S. Pat. No. 6,786,040. Characteristic of this example is the short design of the auxiliary power units, or boosters (2720), in order to maximize aerodynamics and reduce costs, or save weight. The reduced weight is advantageous for landing by braking chute after burnout. Fuel is supplied from the lower stage (2710) or its tanks. The geometry of the air-breathing thrusters (2721) is flexible according to the concept of
[0282] After separation of the auxiliary power systems or boosters (2720) at an altitude of about 100,000 ft or about 30 km, they are returned to the earth's surface by braking chute to enable reuse. Alternatively, a propulsive landing can be attempted via additional tanks.
[0283] The rocket is further accelerated by the lower stage (2710) with the conventional rocket engines. After its burnout, further acceleration is performed by the upper stage (2730) or, if necessary, the intermediate stage. The payload (2740) is accelerated into the corresponding orbit.
[0284]
[0285] This example is further approximated to
[0286]
[0287] Compared with the embodiments of
[0288] As shown in
[0289]
[0290] Compared to
[0291] On both sides of the widened fins (3026) there are 4 air-breathing engine systems (3021) with intermediate bodies and flat inlets. Advancing inflow flaps (3022) with free space between them (3024) prevent the air from flowing around them as far as possible. The result is a tapered shape with maximum width at the engine inlets of the air-breathing engine systems (3021). The outer nacelles (3025) of the air-breathing engine systems (3021) are connected to the fuselage of the remaining auxiliary power units (3020) via side webs. Fuel tanks, turbopumps, etc. are located in these auxiliary power units (3020).
[0292] The rocket (2700) is launched with the lower stage (2710). By additionally feeding in an oxidizer, the air-breathing auxiliary power units (3020) are self-launching (e.g. patent specification DE 10 2021 000 530.9) and accelerate the rocket (2700) along with it. By increasing the incoming air mass flow (30), the thrust of the auxiliary power units (3020) increases. The additional feed of the oxidizer can be stopped at a certain velocity. In this embodiment, this is from about Mach 0.75. To increase the capability of the air-breathing engine systems (3021) for low-pressure inflow, the intermediate body is minimized, i.e. retracted. In addition, the additional inflow surfaces of the inflow flaps (3022) accelerate the air mass flow (30). As shown in
[0293] Depending on the incoming air mass flow (30), the conventional engine systems of the lower stage (2710) may be switched off, varied in intensity, or re-ignited. In the case of reduced incident flow of the air mass flow (30), the additional feed of oxidizers can be restarted if necessary in order to utilize the decreasing air mass flow (30) as long as possible and to be able to use it energetically for effective acceleration.
[0294] To increase the controllability of the engines and their performance, reference is made to patent applications DE 10 2021 000 701.8, DE 10 2021 001 272.0, DE 10 2021 004 141.0. Variable loads of catalytic absorbers are fed into the engines (2721) and ignited/stimulated by electromagnetic waves (e.g. by microwaves).
[0295] Upon reaching an altitude of approximately 100,000 ft, or 30 km, the air-breathing auxiliary power units (3020) are disconnected. This altitude can alternatively be further increased at maximized orbital inclination with maximized speed and additional loads of catalysts to avoid flameout and pressure losses.
[0296] Subsequently, the rocket (2700) with lower stage (2710) and subsequent stages (2730) with the payload (2740) can be accelerated toward the target orbit.
[0297] It should be noted that the arrangement of a central two-stage rocket (2700) with payload and two lateral auxiliary power systems has a superficial similarity with a Falcon Heavy. However, key parameters for stage separation and type of propulsion systems are different from the Falcon Heavy.
[0298] In addition, a special separable missile can possibly be further developed from the basic shape of
[0299] A significant effect and relevance for the Heber Concept is the additional inflow, i.e. acceleration and possible further compression, in this technically demanding but particularly interesting limit range. Reference has already been made to the advantages of designing conventional rocket engines of the lower stage (2710) for altitude ranges with low pressure (solution of the task, engine systems). The Heber Concept explicitly does not preclude subsequent energetically oriented acceleration flights. At high altitudes, the remaining mass of the rocket causes a significantly higher energy conversion in the velocity dimension than at altitude. Further explanations follow in
[0300] This reflects the energy in height in the gravity system of the earth and velocity at rocket launch.
[0301] In (3100), a simplified energy balance is based on the parameters of the International Standard Atmosphere (ISA), or on the example of a Falcon 9 rocket launch. On the horizontal axis (3101) are bars for altitudes in [km] and on the vertical axis (3102) the fractions in [%].
[0302] The total energy of the instantaneous rocket mass is considered simplified from proportions [%] of potential energy (3111) and kinetic energy (3112) along the altitude. Potential energy is balanced as the product of mass times acceleration due to gravity times altitude (“m*g*h”) and kinetic energy is balanced as the product of half the mass times the square of the velocity (“1/2*m*v.sup.2”). Above about 100,000 ft, or 30 km altitude, the power of the engines is predominantly converted to kinetic energy. The energy conversion in the velocity dimension is roughly twice as extensive.
[0303]
[0304] Limit values for air-breathing engine systems according to the current state of the art are shown on the horizontal axis (
[0305] On the vertical axis, the energy fractions are shown in [%] (3202). The kinetic energy increases from state 1 to 2 by more than 2,000,000 Nm/kg, whereas the potential energy “only” increases by approx. <100,000 Nm/kg. The reason for the one order of magnitude different increase is the input of the velocity squared (Epot=1/2mv.sup.2). This means that for further energy conversion, a development of air-breathing engine systems for high altitudes and velocities is technologically particularly valuable. High altitudes cause less frictional heat with reduced atmospheric density, for example. Reference is made to the other patent applications DE 10 2021 000 701.8, DE 10 2021 001 272.0 and DE 10 2021 004 141.0.
[0306] According to
[0307] This effect is less interesting for lower speeds/altitudes and, on the basis of the explanations in
[0308] What is described herein are specific examples of possible variations on the same invention and are not intended in a limiting way. The invention can be practiced using other variations not specifically described above.