Abstract
Apparatus, systems and methods for pumping fluids, including for the purpose of controlling temperature and pressure in a propellant tank include a type of novel ejector, consisting of a typical ejector and an isolation valve integrated on the inlet of secondary fluid to an ejector, or suction chamber. The inlet valve is actuated by the application of the primary motive fluid pressure to a motive nozzle. The ejector is configured to operate when submerged in the secondary fluid.
Claims
1. An assembly for pumping fluids, comprising: a. an ejector having a body, the body defining a suction chamber having a suction chamber inlet, and a nozzle extending from the ejector body, the ejector body configured to operate when the ejector body is submerged in a liquid volume; b. the suction chamber inlet disposed within a liquid volume; c. a valve disposed within the ejector body and in fluid communication with the liquid volume via the suction chamber, the valve having an open position that permits passage of the liquid volume to the suction chamber and a closed position that isolates the suction chamber from the liquid volume; d. a motive fluid in fluid communication with the ejector, wherein transmission of the motive fluid at or above a threshold pressure causes an actuator of the valve to mechanically translate from the closed position to the open position by application of a motive fluid pressure to the valve and which motive fluid also causes a suction effect when passing through the nozzle which draws a portion of the liquid volume into the suction chamber, and the actuator is mechanically translated to the closed position by reducing the motive fluid pressure below the threshold pressure.
2. The assembly of claim 1, wherein the motive fluid is pressurized above the threshold pressure.
3. The assembly of claim 2, further comprising a pump in fluid communication with the motive fluid and configured to pressurize the motive fluid.
4. The assembly of claim 1, wherein the actuator of the valve comprises a mechanical actuator movable between a first position and a second position.
5. The assembly of claim 4, further comprising a valve body connected to the mechanical actuator, wherein when the mechanical actuator is in the first position, the valve is closed and when the mechanical actuator is in the second position the valve is open.
6. The system of claim 5, wherein the mechanical actuator comprises a piston movable between the first position and the second position and a stem interconnecting the piston with the valve body.
7. The system of claim 6, further comprising a biasing member that biases the piston to the first position and biases the valve to the closed position.
8. The assembly of claim 1, wherein the valve comprises a poppet valve.
9. The assembly of claim 1, wherein the valve comprises a globe valve.
10. The system of claim 1, further comprising a syphon tube having a first end and a second end spaced from the first end, wherein the first end is in fluid communication with the valve inlet and the second end is configured to be in fluid communication with a liquid propellant.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Those of skill in the art will recognize that the following description is merely illustrative of the principles of the invention, which may be applied in various ways to provide many different alternative embodiments. This description is made for illustrating the general principles of the teachings of this invention and is not meant to limit the inventive concepts disclosed herein.
(2) FIG. 1 is a schematic diagram of one embodiment of an upper or second stage of a launch vehicle including a system for controlling ullage temperature and pressure.
(3) FIG. 2A is a cross-sectional view of one embodiment of a non-operating jet pump assembly inside a propellant tank.
(4) FIG. 2B is a cross-sectional view of the embodiment of FIG. 2A, with the jet pump assembly operating and showing propellant entering a syphon.
(5) FIG. 2C is a cross-sectional view of the embodiment of FIG. 2A, with the jet pump assembly operating and showing motive fluid and propellant mixing in a mixing tube and exiting the mixing tube into a propellant tank.
(6) FIG. 2D is a cross-sectional view of the embodiment of FIG. 2A, with the jet pump assembly operating and showing a volume of ullage at a temperature lower than the temperature of the ullage generally.
(7) FIG. 2E is a cross-sectional view of the embodiment of FIG. 2A showing the effect of continuing operation of the jet pump assembly.
(8) FIG. 3 is a schematic diagram of a propellant tank containing an alternative embodiment of a jet pump assembly.
(9) FIG. 4 is a schematic diagram of a propellant tank containing multiple jet pump assemblies.
(10) FIG. 5 is a schematic diagram of an alternative embodiment of an upper or second stage of a launch vehicle including a system for controlling ullage temperature and pressure.
(11) FIG. 6 is a schematic diagram of a further alternative embodiment of an upper or second stage of a launch vehicle including a system for controlling ullage temperature and pressure.
(12) FIG. 7 is a schematic diagram of another alternative embodiment of an upper or second stage of a launch vehicle including a system for controlling ullage temperature and pressure.
(13) FIG. 8 is a schematic diagram of a further alternative embodiment of jet pump partially submerged in a liquid and including an inlet valve to control liquid flow to the jet pump.
(14) FIG. 9 is the embodiment of FIG. 8, showing an inlet valve in an open position and the introduction of a motive fluid.
(15) FIG. 10 is the schematic view of FIG. 9, further showing liquid being drawn in to the jet pump and a mixture of liquid and motive fluid exhausted from the jet pump.
(16) FIG. 11 is a schematic diagram of an alternative embodiment of the jet pump of FIG. 8 (add syphon tube extension).
(17) FIG. 12 is a schematic diagram of a further alternative embodiment of a jet pump.
(18) FIG. 13 is a schematic of the embodiment of FIG. 12, with the valve open.
(19) The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of the invention.
(20) The drawings are not necessarily to scale and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.
DETAILED DESCRIPTION
(21) Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
(22) FIG. 1 illustrates a first embodiment of a propellant system for a launch vehicle 10. Two propellant tanks 12 and 14 are shown in coaxial alignment. Each tank contains a liquid cryogenic propellant, for example, oxygen 40 in tank 12 or hydrogen 42 in tank 14. A propellant supply line 16 connects the upper tank 12 to the engine 18. A second propellant supply line 20 connects the lower tank 14 to the engine 18. The two propellants are mixed and combusted by the engine 18. A valve 22 may be provided in association with the upper tank 12 to supply propellant to or vent propellant from the upper tank 12. Similarly, a second valve 24 may be provided in association with the lower thank 14 to supply propellant from the tank 14.
(23) Using the upper tank 12 for discussion purposes, FIG. 1 shows an aerodynamic jet pump assembly 30 comprising a motive nozzle 32 disposed in the proximal end of a mixing tube 34, a syphon 36 in fluid communication with the mixing tube 34 and having a distal end 38 disposed in liquid cryogenic propellant 40. A source 44 of pressurized motive fluid 46 is in fluid communication with the motive nozzle 32 by a supply line 48. A valve 50 controls the supply of motive fluid 46 to the motive nozzle 32. The motive fluid 46 is maintained under pressure within the source 44. When the valve 50 is opened, motive fluid 46 will flow to the motive nozzle 32 and when the valve 50 is closed, no motive fluid will be supplied to the motive nozzle 32. The motive fluid 46 may be the same as the propellant, for example, liquid oxygen in the case of tank 12 or some other cryogenic propellant. Alternatively, the motive fluid may be different from the propellant, for example, helium or some other element or composition that would not adversely affect the propellant.
(24) Tank 14 uses a second jet pump assembly 30 that is the same as jet pump assembly 30 associated with tank 12. The same reference numerals, further including a prime () symbol, are used to designate duplicate components associated with tank 40. Thus, the jet pump assembly 30 includes a motive nozzle 32, a mixing tube 34, and a syphon 36 with a distal end 38. Here, because propellant tank 14 contains liquid hydrogen, the source 44 associated with tank 14 may contain liquid hydrogen as the motive fluid 46. A valve 50 controls the flow of pressurized motive fluid 46 in supply line 48 to the tank 14.
(25) Turning to FIGS. 2A-2E, operation of the jet pump assembly 30 will be described. Jet pump 30 operates in the same way. FIG. 2A illustrates the jet pump assembly 30 in a static or non-operating state. The jet pump assembly 30 includes a jet pump body 31 housing a motive nozzle 32 and defining a suction chamber 33. A mixing chamber or mixing tube 34 and a syphon 36 extend from the ejector body 31. As seen, the distal end 38 of the syphon 36 is positioned within the liquid propellant 40. The motive nozzle 32 and mixing tube 34 are not positioned in the liquid propellant but are positioned in ullage or gaseous propellant 60. It will be appreciated by those of skill in the art that a propellant tank will rarely, if ever, be filled completely with liquid cryogenic propellant. Rather, some portion of the propellant in the tank will be in a gaseous statealso known as ullage. Also, the position of the interface between the liquid and gaseous propellant will change over time and will not always be demarcated by a planer surface as illustrated in the drawings of this disclosure which are provided for illustrative purposes and not intended to depict every possible scenario of liquid and gaseous propellant cohabitating in a single propellant tank. The label Tliq represents the temperature of the liquid cryogenic propellant 40. The label TU represents the temperature of the ullage 60. The temperature of the liquid cryogenic liquid propellant will always be less than that of the ullage 60 (Tliq<TU).
(26) In FIG. 2B, valve 50 is open and pressurized motive fluid 46 is flowing from the source 44 to the motive nozzle 32. The condensable motive fluid 46 is accelerated through the nozzle 32 to create a high velocity fluid stream or jet that reduces local static pressure and thereby creates a vacuum. The nozzle 32 may be configured as a subsonic, sonic or supersonic nozzle. Consistent with Bernoulli's principle, an area or zone of low static pressure 64 is created proximate the exit 66 of the motive nozzle 32. An effect of the low-pressure area 64 is that the liquid propellant 40 is drawn through the syphon 36 to a suction chamber 33 and then into the mixing chamber or mixing tube 34 as seen in FIG. 2C.
(27) FIG. 2C illustrates mixing of the liquid propellant 40 with the motive fluid 46. More particularly, as motive fluid 46 continues to be supplied to the motive nozzle 32, the propellant 40 will be fully drawn into the mixing tube 34 where it will mix with or be entrained into the high velocity motive fluid 46 exiting the motive nozzle 32. The two fluids mix to form a highly atomized spray or mixture 70 of both the liquid cryogen propellant 40 and the motive fluid 46 through momentum transfer between the coflowing fluids.
(28) FIG. 2D illustrates the creation of an area 72 of reduced temperature within the ullage 60 proximate the exit 74 of the mixing tube. More particularly, the condensable motive fluid 46 is cooled by the mixing with the liquid cryogenic propellant 40. As a result, the temperature T of the area 72 is less than the temperature TU of the ullage 60 and greater that the temperature Tliq of the propellant 40 (Tliq<T<=TU). Because evaporation is occurring, if the process continues the temperature of the area 72 and the temperature of the ullage (TU) could reach an equilibrium and approach or reach the temperature of the liquid propellant (TU). Vaporization of the liquid droplets in the mixture efficiently cools the ullage. Because the resulting mixture of the motive fluid 46 and the liquid propellant 40 has a lower temperature than the ullage 60, the temperature of a localized volume 72 of the ullage is reduced and the total pressure of the ullage 60 is reduced or at least not increased. The arrow VP illustrates that the volume of the liquid propellant 40 diminishes as the result of syphoning liquid propellant 40 to mix with the motive fluid 32. The arrow V72 illustrates that the volume of the localized area 72 increases based upon the duration of the operation of the jet pump assembly 30. Indeed, as the jet pump assembly continues to operate, the volume of area 72 will increase as generally illustrated in FIG. 2E expanding the volume V72 of reduced temperature ullage and further reducing the pressure within the propellant tank.
(29) The present invention is superior to a detachable ground-only conditioning system for several reasons, including: 1) it has the unique capability to condition the ullage in flight to reduce the effects of aero heating and ambient helium pressurization, 2) it is more cost effective, 3) it is less complicated, 4) there are no additional moving parts, and 5) the ambient helium and the ullage gas are cooled.
(30) By using forced convective vaporization as explained above, a propellant tank may be filled with cryogenic liquid propellant without a need to vent the tank during the fill operation. The operation introduces a motive fluid in the form of a condensable, pressurized and atomized cryogenic liquid propellant into the tank ullage to decrease the ullage gas temperature in a controlled manner. In the specific example of FIG. 1, the vehicle 10 includes two propellant tanks 12 and 14, each with a different cryogenic propellant. Cryogenic liquid oxygen may be in one tank and cryogenic liquid hydrogen in the other. In this context, where the motive fluid is condensable, cryogenic liquid oxygen may be the motive fluid for the oxygen tank 12 and cryogenic liquid hydrogen may be the motive fluid for the hydrogen tank. In this scenario, cryogenic liquid oxygen should not be added to the tank containing cryogenic liquid hydrogen. In other scenarios, it may be acceptable to utilize a single common condensable motive fluid for each propellant tank 12 and 14. The motive fluid need not be continuously supplied to the motive nozzle but may be pulsed repeatedly, intermittently stopped and started or the nozzle 50 and 50 may be throttled proportionally to regulate the cooling in the tank and control pressure. In FIGS. 1 and 2A-2E, the jet pump assembly 30 is shown at a position adjacent a perimeter wall of the tank. As illustrated in FIGS. 3 and 4, the jet pump assembly 30 may be positioned in the center of the tank or at another location based upon other factors. The assembly may also be configured to rotate or oscillate to disperse the atomized mixture over a larger volume. In alternative embodiments, multiple jet pump assemblies may be included in a single tank. In addition, the source 44 of the motive fluid 46 is show outside of the tank 12. In a non-limiting alternative embodiment, the source 30 may be positioned inside the tank 12. Further still, FIG. 1 shows a separate source 44 and 44 for each tank 12 and 14, respectively. A single source tank may supply motive fluid to both tanks 12 and 14 in appropriate circumstances and under appropriate conditions as would be understood by those of skill in the art upon review of the present disclosure.
(31) FIG. 5 illustrates another embodiment of a system for controlling propellant tank temperature and pressure for use in filling propellant tanks with cryogenic liquid propellant without the need to vent the tank. An upper or second stage 100 of a launch vehicle is shown. The vehicle contains a first propellant tank 112 for holding a first cryogenic liquid propellant 140 and a second propellant tank 114 for holding a second cryogenic liquid propellant 142. A propellant supply line 116 connects the upper tank 112 to the engine 118. A second propellant supply line 120 connects the lower tank 114 to the engine 118. The two propellants are mixed and combusted by the engine 118. A valve 122 may be provided in association with the upper tank 112 to supply propellant to or vent propellant from the upper tank 112. Similarly, a second valve 124 may be provided in association with the lower thank 14 to supply propellant or vent propellant from the tank 114.
(32) The upper tank 112 further includes an atomizer 130 connected to a source 144 of a pressurized, motive fluid 146 that is supplied to the atomizer 130 by a supply line 148. A valve 150 controls the flow of motive fluid 146 to the atomizer 130. The lower or second tank 114 includes the same components. An atomizer 130 is connected to a source 144 of a pressurized, motive fluid 146 that is supplied to the atomizer 130 by a supply line 148. Nozzle 150 controls the flow of the motive fluid 146 to the atomizer 130.
(33) The embodiment of FIG. 6 illustrates a further alternative. Here, the motive fluid is the cryogenic liquid propellant in each of the tanks 112 and 114. A pump 180 is provided in association with the first tank 112 and a pump 180 is provided in association with the second tank 114 to withdraw the propellant from the tank and forward it to the atomizers 130 and 130. In one non-limiting example, the pumps 180 and 180 are centrifugal pumps. Alternative pumps could be of the positive displacement variety.
(34) The embodiments illustrated in FIGS. 5 and 6 may also be used to control ullage temperature and pressure within a propellant tank containing cryogenic liquid propellant. In operation, a condensable motive fluid under pressure is supplied to the atomizer 130 and 130 which atomizes the motive fluid and disperses it into the ullage of a propellant tank containing a liquid cryogenic propellant. Similar to the embodiments that utilize a jet pump assembly, the atomized spray has a temperature less than that of the ullage. In one non-limiting example regarding the embodiment of FIG. 5, the motive fluid 146 and 146 is the same liquid propellant as contained in the propellant tank. In other non-limiting examples involving the embodiment of FIG. 5, the motive fluid may be cryogenic liquid helium or nitrogen. The atomized spray creates a volume or localized area having a temperature less than that of the ullage generally, which reduces pressure within the tank. Continuing to supply the motive fluid to the atomizer further reduces the temperature of the ullage and further controls pressure within the tank.
(35) In the embodiments of FIGS. 5 and 6, the motive fluid 146 and 146 need not be continuously supplied to the atomizer 130 and 130 but may be pulsed repeatedly, intermittently stopped and started or the nozzle 150 and 150 may be throttled proportionally to regulate the cooling in the tank and control pressure. In FIGS. 5 and 6, the atomizers 130 and 130 are shown at a position adjacent a perimeter wall of the tank. Similar to the jet pump assembly embodiments illustrated in FIGS. 4 and 5, the atomizers 130 and 130 may be positioned in the center of the tank or at another location based upon relevant factors. The atomizer may also be configured to rotate or oscillate to disperse the atomized mixture over a larger volume. In alternative embodiments, multiple atomizers may be included in a single tank. In addition, the source 144 and 144 of the motive fluid 146 and 146 are shown outside of the tank 12. In a non-limiting alternative embodiment, the source 144 and 144 may be positioned inside the tank 112 and 114. Further still, FIG. 5 shows a separate source 144 and 144 for each tank 112 and 114, respectively. A single source tank may supply motive fluid to both tanks 112 and 114 under appropriate circumstances and under appropriate conditions as would be understood by those of skill in the art upon review of the present disclosure.
(36) The embodiment illustrated in FIG. 7 is an alternative to the embodiments of FIGS. 1 and 3-5. Here, a single motive fluid source 44 provides pressurized, incondensable motive fluid to the jet pump assemblies 30 and 30. Because there are two different cryogenic propellants involved, the motive fluid should not be one of the propellants but rather a fluid that is incondensable in both propellants like helium. As with all of the embodiments disclosed herein, the propellant tanks may be conditioned separately or simultaneously.
(37) There may be circumstances in which it is desirable to submerge or partially submerge the body of a jet pump within a liquid, i.e., within a liquid propellant in a tank or container containing liquid and gaseous propellant. One example is illustrated in FIG. 8 where the body 236 of an ejector or jet pump 230 is partially submerged in liquid propellant 240 within a propellant tank 212. As also seen, a supply line 248 supplies motive fluid, under pressure, to a nozzle 232 positioned inside the body 236 of the ejector or jet pump 230. In such a scenario, it also may be desirable to control or limit when the liquid 240 is allowed into the interior of the jet pump 230. Allowing the liquid to remain continuously inside the jet pump could cause or accelerate damage to the jet pump. For example, the liquid 240 may comprise a strong acid or a strong base that can harm special coatings on the internal components of the pump 230. Prolonged exposure to liquid hydrogen can lead to hydrogen embrittlement in the internal metal components. In addition, an on-going presence of the liquid 240 inside the jet pump could cause the liquid to infiltrate the motive fluid supply line 248 and motive fluid source, which could lead to contaminating the motive fluid affecting the properties of the motive fluid causing blockages and icing of the motive supply line and the motive fluid source container may not be rated for the cold temperatures of the liquid 240 also causing damage to this hardware. Chemical reactions between the motive fluid and liquid may also cause unintended pressure increases. Additionally, the presence of a liquid slug in the mixing tube 34, above the motive nozzle 232, prior to jet pump operation could expel an unmixed liquid slug into the ullage that would lead to a start-up transient of the jet pump that may excessively cool the ullage or otherwise lead to inconsistent behavior.
(38) Accordingly, in this embodiment, the jet pump 230 is provided with an inlet valve 250 to control the ingress of liquid 240 into the interior of the jet pump. As illustrated in FIG. 8 the inlet valve 250 includes an isolation valve 252 that has a closed state (FIG. 8) and an open state (seen in FIG. 9). The isolation valve 252 included a valve body 254 connected to a piston 256 by a valve stem 258. Motive fluid 246 is introduced into the jet pump 230 via supply line 248. Turning to FIG. 9, the pressure of the motive fluid 246 forces a portion of the motive fluid 246a to travel through the nozzle 232 to create a high velocity fluid stream or jet that reduces local static pressure and thereby creates a vacuum as discussed herein in connection with other embodiments. A second portion of the pressurized motive fluid 246b displaces piston 256 downwardly or outwardly in the context of FIG. 9. The piston 256 is biased to the closed position illustrated in FIG. 8 by spring 260. Therefore, the force of the motive fluid 246b must be sufficient to overcome the force of the spring 260. When in the closed position illustrated in FIG. 8, the valve body 254 is positioned in a seat 262 formed at the liquid inlet 264 of the pump 230. A gasket or similar seal 266 may be provided on the valve body 254 or around the inlet 264 to facilitate creating a liquid seal when the valve body 254 is closed. Upon the motive fluid 246b displacing the piston 256, the rod or stem 258 displaces the valve body 254 to open the inlet 264. Simultaneously, as a result of the low-pressure zone generated by the motive fluid 246a passing through the nozzle 232, liquid propellant 240a is syphoned or drawn into the suction chamber 233 and then to the mixing chamber 234 as illustrated in FIG. 10. As long as the motive fluid 246 is delivered at or above a threshold pressure needed to displace the piston 256, the valve body 254 will remain open. Ceasing the supply of the motive fluid 246 will cause the valve body 254 to close as illustrated in FIG. 8. It should be appreciated that the liquid inlet 264 of the isolation valve 252 may be in direct communication with a liquid 240, as illustrated in FIGS. 8-10 where the ejector body 236 is submerged in the liquid 240 or, alternatively, as illustrated in FIG. 11, a suction or syphon tube 268 may extend from the valve 252 to allow the jet pump 230 to draw liquid from a farther distance.
(39) FIGS. 12 and 13 show an embodiment according to the present disclosure in service on process piping. Here, the jet pump is used to suction fluid from main process piping. Non-limiting examples include suctioning fluid into an unprimed line before a primary fluid process commences, generating a vacuum in association with a primary process, e.g., in-space rocket engine testing or thermal vacuum testing, moving fluid from a primary process to a secondary process, or in any operation that requires the isolation valve to be closed when the ejector is not in operation. Turning to the FIGS. 12 and 13, a primary fluid line or pipe 300 and a secondary line or pipe 302 are shown. A jet pump 330 is positioned in the secondary line 302 which is in fluid communication with the primary line 300. When valve 350 is opened, motive fluid 346 under pressure from motive fluid source 344 is released into motive fluid supply line 348. The motive fluid 346 splits with a first portion 346a entering the jet pump 330 and a second portion 346b engaging a piston 356 that is part of isolation valve 352. The force of the motive fluid portion 346b overcomes the counter force of spring 360 and the piston is moved downwardly as illustrated in FIG. 13. Downward movement of piston 356 cause valve stem 358 to open the valve body 354. The valve body 354 rests in or on a valve seat 362 when closed. A gasket or seal 366 may be provided on the valve body 354 or around the seat 362. As a result of a low pressure area created by motive fluid 346a exiting nozzle 332, primary fluid 340a is drawn through the opening 364 of the isolation valve 352 and into a suction chamber 333 and then into the mixing chamber 334 of the jet pump 330 where it mixes with motive fluid 346a. The motive fluid pressure opens the secondary fluid inlet valve 354 and subsequently draws in the process fluid 340a from the process or primary pipe 300, pumps this fluid out of the process pipe 300 to secondary process(es), or simply reduces the pressure in the main process piping 300 to prime the line, create vacuum, or to evacuate the line to bring the process into or out of service. Once the ejector 330 has completed its operation, the motive fluid pressure supply is isolated and the secondary fluid inlet valve 354 is closed, effectively isolating the jet pump 330 and its downstream process from the main process.
(40) At least some of the embodiments illustrated and discussed herein may be used for purposes other than filling a propellant tank with a liquid cryogenic propellant without needing to vent the tank. In particular, embodiments illustrated and described may be used to reduce or eliminate the occurrence of ullage collapse. In the embodiments illustrated in FIGS. 1-4 and 7-13, an incondensable or non-condensable fluid may be used in place of the condensable motive fluid. The incondensable motive fluid is accelerated through a nozzle to create a high velocity fluid jet that reduces local static pressure and thereby creates a vacuum. The low static pressure suctions liquid cryogen out of the liquid space within the propellant tank where it is entrained into the flow of the high velocity motive fluid, preferably within a mixing chamber or tube, to form a highly atomized spray of both the liquid cryogen and the motive fluid through momentum transfer between the coflowing fluids. The mixed solution is then exhausted into the ullage space of the propellant tank where evaporation of the atomized spray lowers the ullage gas temperature. In the embodiment of FIG. 6, the motive fluid is accelerated through an atomizer creating a highly atomized spray that has a temperature lower than that of the ullage generally. Because a non-condensable motive fluid is used, total pressure of the ullage is increased. By reducing or minimizing the thermal potential energy, e.g., the difference in temperature between the ullage gas and the temperature of the liquid cryogenic propellant, the degree by which the ullage pressure can collapse is reduced and the risk or ullage collapse is also reduced or perhaps eliminated.
(41) While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
(42) The foregoing discussion of the disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more embodiments, configurations, or aspects for the purpose of streamlining the disclosure. The features of the embodiments, configurations, or aspects of the disclosure may be combined in alternate embodiments, configurations, or aspects other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.
(43) The features of the various embodiments described herein are not intended to be mutually exclusive when the nature of those features does not require mutual exclusivity. Instead, features and aspects of one embodiment may be combined with features or aspects of another embodiment. Additionally, the description of a particular element with respect to one embodiment may apply to the use of that particular element in another embodiment, regardless of whether the description is repeated in connection with the use of the particular element in the other embodiment.
(44) Examples provided herein are intended to be illustrative and non-limiting. Thus, any example or set of examples provided to illustrate one or more aspects of the present disclosure should not be considered to comprise the entire set of possible embodiments of the aspect in question. Examples may be identified by use of the terms or phrases for example, such as, by way of example, e.g., and other language commonly understood to indicate that what follows is an example.
