On-orbit low-loss storage system and method for cryogenic propellant for deep space probes

Abstract

The present invention relates to the field of deep space exploration technology, and in particular to a low-loss on-orbit storage system and method for cryogenic propellants used in deep space probes. After the cryogenic propellant is filled into the tank through a filling pipe, as external heat leakage continues to accumulate, the first pressure sensor detects that the pressure in the tank continues to rise. When the value of the first pressure sensor exceeds a preset pressure, the cooling component is activated to cool the cryogenic propellant in the tank, thereby absorbing the external heat leakage. Before the engine needs to supply the cryogenic propellant, the cryogenic propellant in the tank is in a supercritical state, and the storage temperature is increased by a high-pressure storage method, thereby reducing the temperature difference between the tank and the outside world and the amount of heat leakage, and thus the cooling capacity demand of the cooling component is also reduced. When the cryogenic propellant is transported, since it is in a supercritical state, there is no distinction between gas and liquid phases, and the entire tank is in a homogeneous state, which can ensure the stability of the cryogenic propellant delivery flow and is also conducive to the stable output of the engine.

Description

Technical Field

[0001] The present invention relates to the field of deep space exploration technology, and in particular to an on-orbit low-loss storage system and method for cryogenic propellant used in deep space probes. Background Art

[0002] Cryogenic propellants (such as liquid methane, liquid hydrogen, and liquid oxygen) offer significant advantages in deep space exploration missions. Their high energy density provides powerful thrust for probes, significantly increasing their carrying capacity. Their clean combustion products effectively avoid disrupting the target environment. Furthermore, their relatively low cost and resource consumption make them ideal for the long-distance, high-payload requirements of deep space exploration, making them a key power source of choice.

[0003] However, controlling evaporation losses from cryogenic propellants stored on-orbit during deep space exploration missions presents a significant challenge. Due to the complex space environment, cryogenic propellants are highly susceptible to thermal evaporation. For example, liquid methane, with a boiling point of only -161.5°C at atmospheric pressure, can cause significant evaporation of cryogenic propellants in the intense heat encountered during in-orbit flight, severely limiting the operational lifespan of deep space probes. Furthermore, deep space probes require periodic venting to maintain tank pressure. However, the gas-liquid mixture (the cryogenic propellant present in the tank) is difficult to effectively separate in the microgravity of space. Consequently, significant amounts of liquid cryogenic propellant are entrained during the venting process, further exacerbating cryogenic propellant losses.

[0004] Therefore, there is an urgent need for an on-orbit low-loss storage system and method for cryogenic propellants for deep space probes to solve the above technical problems. Summary of the Invention

[0005] Embodiments of the present invention provide a system and method for on-orbit low-loss storage of cryogenic propellant for a deep space probe, which can achieve on-orbit low-loss storage of cryogenic propellant.

[0006] In a first aspect, an embodiment of the present invention provides an on-orbit low-loss storage system for cryogenic propellants for a deep space probe, comprising a tank for accommodating cryogenic propellants, the tank being provided with an exterior thermal insulation layer, the tank being connected to a filling pipe, a discharge pipe, and a cooling assembly, the discharge pipe being sequentially connected to a throttling delivery pipe, a heat exchange pipe, and a supply pipe along a delivery direction of the cryogenic propellant, the throttling delivery pipe and the supply pipe being both provided outside the thermal insulation layer, the heat exchange pipe being provided between the tank and the thermal insulation layer, the supply pipe being connected to an engine of the deep space probe, the discharge pipe being provided with a first pressure sensor, the throttling delivery pipe being provided with a throttle valve and a regulating valve, and the supply pipe being provided with a second pressure sensor and a flow sensor;

[0007] After the cryogenic propellant is filled into the tank through the filling pipe, as external heat leakage continues to accumulate, the first pressure sensor detects that the pressure in the tank continues to rise. When the value of the first pressure sensor exceeds a preset pressure, the cooling component is activated to cool the cryogenic propellant in the tank.

[0008] When the engine needs to be supplied with cryogenic propellant, the cryogenic propellant is sequentially supplied to the engine through the discharge pipe, the throttling delivery pipe, the heat exchange pipe, and the supply pipe, and the supply pressure and supply flow of the cryogenic propellant are adjusted by the throttle valve and the regulating valve, respectively. Before the engine needs to be supplied with cryogenic propellant, the cryogenic propellant in the tank is in a supercritical state, and the preset pressure is higher than the minimum pressure of the cryogenic propellant when it is in the supercritical state.

[0009] In a second aspect, an embodiment of the present invention provides a method for low-loss on-orbit storage of cryogenic propellant for a deep space probe, which is applied to the system described in the above embodiment. The method includes a cryogenic propellant filling stage, a cryogenic propellant storage stage, and a cryogenic propellant delivery stage in a progressive manner, wherein:

[0010] The cryogenic propellant storage phase includes:

[0011] The initial pressure inside the tank after filling is one atmosphere, and the initial stage of the storage phase relies on the passive insulation of the thermal insulation layer;

[0012] As external heat leakage continues to accumulate, the pressure inside the tank continues to rise. When the pressure inside the tank exceeds a preset pressure, the cooling component is activated to cool the cryogenic propellant in the tank, thereby absorbing the external heat leakage.

[0013] Compared with the related art, the present invention has at least the following beneficial effects:

[0014] According to the low-loss on-orbit storage system and method for cryogenic propellant for deep space probes provided by an embodiment of the present invention, after the cryogenic propellant is filled into the tank through the filling pipe, as the external heat leakage continues to accumulate, the first pressure sensor detects that the pressure in the tank is constantly rising. When the value of the first pressure sensor exceeds the preset pressure, the cooling component is started to cool the cryogenic propellant in the tank, thereby absorbing the external heat leakage; before the engine needs to supply the cryogenic propellant, the cryogenic propellant in the tank is in a supercritical state, and the cryogenic propellant in the tank is in a supercritical state, and the high-pressure storage method is used to store the cryogenic propellant. High storage temperature reduces the temperature difference between the tank and the outside world and the amount of heat leakage, which in turn reduces the cooling capacity demand of the cooling assembly. During cryogenic propellant transportation, since it is in a supercritical state and there is no distinction between gas and liquid phases, the entire tank interior is in a homogeneous state, which ensures a stable cryogenic propellant delivery flow and is also conducive to stable engine output. By controlling the opening of the throttle valve and the regulating valve, the supply pressure and supply flow of the cryogenic propellant are adjusted. After throttling and depressurization, the temperature of the cryogenic propellant drops. When the cryogenic propellant flows through the heat exchange tube, it can exchange heat with the tank wall, thereby reducing the power consumption of the cooling assembly. Therefore, the above technical solution can achieve low-loss storage of cryogenic propellant on orbit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of the structure of an on-orbit low-loss storage system for cryogenic propellant for a deep space probe provided by an embodiment of the present invention;

[0017] Figure 2 for Figure 1 The schematic diagram of the structure of the heat exchanger in the on-orbit low-loss storage system is shown.

[0018] Reference numerals:

[0019] 1-Storage tank; 2-Thermal insulation layer; 3-Filling pipe; 4-Discharge pipe; 5-Cooling assembly; 6-Throttling delivery pipe; 7-Heat exchange pipe; 8-Supply pipe; 9-First pressure sensor; 10-Throttle valve; 11-Regulating valve; 12-Second pressure sensor; 13-Flow sensor; 14-Temperature sensor; 15-Overpressure discharge pipe; 16-Safety valve; 17-Active discharge pipe; 18-Stop valve; 51-Refrigerator; 52-Heat exchanger; 53-Circulating pump; 511-Cold head; 521-Heat exchange inlet; 522-Heat exchange outlet; 523-Foam copper. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, an embodiment of the present invention provides an on-orbit low-loss storage system for cryogenic propellants for deep space probes, comprising a tank 1 for accommodating cryogenic propellants, the exterior of the tank 1 being provided with a thermal insulation layer 2, the tank 1 being connected to a filling pipe 3, a discharge pipe 4, and a cooling assembly 5, the discharge pipe 4 being sequentially connected to a throttling delivery pipe 6, a heat exchange pipe 7, and a supply pipe 8 along the delivery direction of the cryogenic propellant, the throttling delivery pipe 6 and the supply pipe 8 being both provided outside the thermal insulation layer 2, the heat exchange pipe 7 being provided between the tank 1 and the thermal insulation layer 2, the supply pipe 8 being connected to an engine of the deep space probe, the discharge pipe 4 being provided with a first pressure sensor 9, the throttling delivery pipe 6 being provided with a throttle valve 10 and a regulating valve 11, and the supply pipe 8 being provided with a second pressure sensor 12 and a flow sensor 13;

[0022] After the cryogenic propellant is filled into the tank 1 through the filling pipe 3, as external heat leakage continues to accumulate, the first pressure sensor 9 detects that the pressure in the tank 1 continues to rise. When the value of the first pressure sensor 9 exceeds the preset pressure, the cooling component 5 is activated to cool the cryogenic propellant in the tank 1.

[0023] When the engine needs to be supplied with cryogenic propellant, the cryogenic propellant is supplied to the engine in sequence through the discharge pipe 4, the throttling delivery pipe 6, the heat exchange pipe 7 and the supply pipe 8, and the supply pressure and supply flow of the cryogenic propellant are adjusted by the throttle valve 10 and the regulating valve 11 respectively; wherein, before the engine needs to be supplied with cryogenic propellant, the cryogenic propellant in the tank 1 is in a supercritical state, and the preset pressure is higher than the minimum pressure when the cryogenic propellant is in the supercritical state.

[0024] In this embodiment, after the cryogenic propellant is filled into the tank 1 through the filling pipe 3, as the external heat leakage continues to accumulate, the first pressure sensor 9 detects that the pressure in the tank 1 continues to rise. When the value of the first pressure sensor 9 exceeds the preset pressure, the cooling component 5 is activated to cool the cryogenic propellant in the tank 1, thereby absorbing the external heat leakage; before the engine needs to supply the cryogenic propellant, the cryogenic propellant in the tank 1 is in a supercritical state. The cryogenic propellant in the tank 1 is in a supercritical state, and the storage temperature is increased by high-pressure storage, thereby reducing the pressure between the tank 1 and the engine. The external temperature difference and heat leakage, and thus the cooling capacity demand of the cooling assembly 5, are also reduced. During cryogenic propellant delivery, since it is in a supercritical state, there is no distinction between gas and liquid phases, and the entire tank interior is in a homogeneous state. This ensures a stable cryogenic propellant delivery flow rate and is also conducive to stable engine output. By controlling the opening of the throttle valve 10 and the regulating valve 11, the supply pressure and supply flow of the cryogenic propellant are adjusted. The temperature of the cryogenic propellant after throttling and depressurization decreases. When the cryogenic propellant flows through the heat exchange tube 7, it can exchange heat with the wall of the tank 1, thereby reducing the power consumption of the cooling assembly 5. Therefore, the above technical solution can achieve low-loss storage of cryogenic propellant on orbit.

[0025] In one embodiment of the present invention, tank 1 is made of carbon fiber composite material, and its maximum allowable pressure is greater than a preset pressure. This configuration not only allows tank 1 to have a higher maximum allowable pressure, facilitating storage at higher pressures, but also reduces tank 1's weight, further extending the usable life of the cryogenic propellant.

[0026] In one embodiment of the present invention, the difference between the maximum allowable pressure and the preset pressure is smaller than the difference between the preset pressure and the minimum pressure. This arrangement allows the preset pressure to be closer to the maximum allowable pressure, thereby further increasing the storage temperature and reducing the refrigeration capacity requirement.

[0027] In some embodiments, the maximum allowable pressure is 75 MPa and the preset pressure is 70 MPa.

[0028] For example, the traditional methane cryogenic propellant storage method uses low pressure (such as 0.3MPa) liquid storage. The boiling point of liquid methane at 0.3MPa is 126.71K, and the density of liquid methane is 399.38kg / m 3 According to the filling rate of 90% of the tank, the storage density of the tank is 359.44kg / m 3 The storage temperature of cryogenic propellant is positively correlated with the storage pressure of the tank. When the storage pressure is increased to 75 MPa, the storage density is 359.44 kg / m 3Under these conditions, the methane storage temperature is 238.5K. Compared to traditional low-pressure liquid storage methods, the high-pressure supercritical storage method mentioned above can raise the storage temperature by over 111K. As a result, the higher the storage temperature, the smaller the temperature difference with the outside world, the lower the heat leakage, and the smaller the cooling capacity required.

[0029] Furthermore, in a microgravity environment, due to the extremely weak gravitational field, the gravitational effect on the gas and liquid is almost negligible, making it impossible to rely on gravity to achieve natural stratification and separation of gas and liquid as on Earth. Therefore, traditional low-pressure liquid storage methods (0.3MPa, 126.71K) often result in a gas-liquid mixture in the tank under microgravity conditions. This unavoidable mixing of gas and liquid during transportation causes fluctuations in the cryogenic propellant flow rate, affecting the stable output of the engine. However, with low-temperature, high-pressure storage (75.0MPa, 238.5K), methane is in a supercritical state, with no gas-liquid phase distinction. The entire tank interior is homogeneous, resulting in a more stable cryogenic propellant supply flow rate, which is conducive to stable engine output.

[0030] The cryogenic propellant supply pressure required by the thrust engines used in deep space probes is often relatively low, usually at 0.2 MPa. It needs to be throttled and reduced in pressure through a throttle valve before it can be supplied to the propulsion engine. The temperature drop generated during the throttling process is recovered through the heat exchange tube, thereby reducing the power consumption of the refrigeration system.

[0031] In one embodiment of the present invention, the tank 1 is further connected to a temperature sensor 14, which is used to detect the real-time temperature of the cryogenic propellant in the tank 1;

[0032] Based on the pressure detected by the first pressure sensor 9 and the temperature detected by the temperature sensor 14 , the current residual amount of cryogenic propellant in the tank 1 is determined.

[0033] In one embodiment of the present invention, the discharge pipe 4 is further connected to an overpressure discharge pipe 15 , and a safety valve 16 is provided on the overpressure discharge pipe 15 ;

[0034] When the external heat leakage is greater than the cooling capacity of the cooling assembly 5 , the safety valve 16 opens.

[0035] In one embodiment of the present invention, the discharge pipe 4 is further connected to an active discharge pipe 17 , and a shut-off valve 18 is provided on the filling pipe 3 , the throttling delivery pipe 6 , and the active discharge pipe 17 ;

[0036] When filling with cryogenic propellant, the stop valves 18 on the filling pipe 3 and the active discharge pipe 17 are both opened;

[0037] When the safety valve 16 fails, the stop valve 18 on the active discharge pipe 17 opens;

[0038] When the engine needs to be supplied with cryogenic propellant, the stop valve 18 on the throttle delivery pipe 6 is opened.

[0039] In one embodiment of the present invention, the cooling assembly 5 includes a refrigerator 51, a heat exchanger 52, and a circulating pump 53 connected in sequence by pipelines. The refrigerator 51 is arranged outside the thermal insulation layer 2, and the heat exchanger 52 and the circulating pump 53 are both arranged inside the tank 1 and are both located on the central axis of the tank 1. The circulating pump 53 is used to suck the cryogenic propellant from the bottom of the tank 1 and send it into the heat exchanger 52. The refrigerator 51 is used to cool the cryogenic propellant entering the heat exchanger 52 so that the cooled cryogenic refrigerant is discharged horizontally from both sides of the heat exchanger 52.

[0040] In this embodiment, a circulating pump 53 draws cryogenic propellant from the bottom of tank 1 and feeds it into a heat exchanger 52 located at the top of tank 1, where it exchanges heat with the cold head of a refrigerator 51. The cooled cryogenic propellant is then discharged horizontally from the side. This specially designed intake and discharge pattern creates a vertical circulation within tank 1, breaking down temperature stratification within the fluid, promoting fluid mixing, ensuring temperature uniformity within the tank, and increasing the rate at which the refrigerated system absorbs heat leaking from the outside.

[0041] like Figure 2 As shown, in one embodiment of the present invention, the heat exchanger 52 includes a vertically arranged heat exchange inlet 521, two horizontally arranged heat exchange outlets 522, and foam copper 523 respectively connected to the heat exchange inlet 521 and the heat exchange outlet 522. The cold head 511 of the refrigerator 51 is inserted into the foam copper 523, and the low-temperature propellant enters the foam copper 523 through the heat exchange inlet 521, and is discharged horizontally through the two heat exchange outlets 522 after heat exchange at the cold head 511.

[0042] In summary, different from the traditional liquid storage concept, the above technical solution uses a composite material high-pressure tank as a container to store methane cryogenic propellant at low temperature and high pressure, ensuring storage density and reducing the temperature difference of heat leakage from the inner tank to the outside, reducing the demand for refrigeration capacity; cooperating with the internal circulation system of the refrigerator to absorb heat leakage and break the temperature stratification inside the tank; the transportation system throttles and regulates pressure, recovers cold energy through the cold screen, and reduces the power consumption of the refrigeration system; it is expected to achieve low-power, low-loss or even zero-loss storage of methane cryogenic propellant in space orbit.

[0043] In addition, one embodiment of the present invention further provides a method for low-loss on-orbit storage of cryogenic propellant for a deep space probe, which is applied to the system mentioned in the above embodiment. The method includes a cryogenic propellant filling stage, a cryogenic propellant storage stage, and a cryogenic propellant delivery stage in a progressive manner, wherein:

[0044] The cryogenic propellant storage phase includes:

[0045] The initial pressure inside the tank 1 after filling is one atmosphere, and the initial stage of the storage phase relies on the passive insulation of the thermal insulation layer 2;

[0046] As external heat leakage continues to accumulate, the pressure inside the tank 1 continues to rise. When the pressure inside the tank 1 exceeds the preset pressure, the cooling component 5 is started to cool the cryogenic propellant in the tank 1, thereby absorbing the external heat leakage.

[0047] In one embodiment of the present invention, the cryogenic propellant delivery stage includes:

[0048] The openings of the throttle valve 10 and the regulating valve 11 are controlled to adjust the supply pressure and flow rate of the cryogenic propellant. The temperature of the cryogenic propellant decreases after throttling and pressure reduction, and as the cryogenic propellant flows through the heat exchange tube 7, it can exchange heat with the wall of the tank 1.

[0049] Based on the pressures detected by the first pressure sensor 9 and the second pressure sensor 12 and the flow rate detected by the flow rate sensor 13 , the openings of the throttle valve 10 and the regulating valve 11 are controlled to maintain the stability of the supply pressure and the supply flow rate.

[0050] It can be understood that the on-orbit low-loss storage method of cryogenic propellant for deep space probes provided in the embodiments of the present invention and the on-orbit low-loss storage system of cryogenic propellant for deep space probes provided in the above embodiments are based on the same inventive concept, and therefore both have the same beneficial effects. The beneficial effects of the on-orbit low-loss storage method of cryogenic propellant for deep space probes will not be elaborated here.

[0051] The specific workflow is described below.

[0052] a. Ground filling of cryogenic propellants:

[0053] Before refueling, ensure that all valves in the storage system are closed, connect the ground vacuum unit to the active discharge pipe, connect the nitrogen source to the filling pipe, open the stop valve on the active discharge pipe, turn on the ground vacuum unit, and evacuate the pressure to below 0.1Pa. Close the ground vacuum unit and the stop valve on the active discharge pipe, open the stop valve on the filling pipe and the ground nitrogen source, and pressurize the storage tank to 0.3MPa. Repeat the vacuuming and pressurizing operations more than three times until the gas in the pipe is completely replaced. Disconnect the ground vacuum unit and the nitrogen source, and connect the filling pipe to the liquid methane tank truck. Open the stop valve on the active discharge pipe and relieve the pressure in the pipe to ambient pressure (i.e. one atmosphere). Open the stop valve on the filling pipe and the liquid outlet valve of the methane tank truck until the remaining volume in the pipe is 90%. Close the stop valve on the filling pipe and the stop valve on the active discharge pipe, and disconnect the liquid methane tank truck.

[0054] b. Cryogenic Propellant Storage:

[0055] The tank's maximum operating pressure is 75 MPa. After filling, the initial pressure inside the tank is 1 atmosphere. During the initial storage phase, the tank relies solely on passive insulation from the composite insulation layer. As external heat leakage accumulates, the pressure inside the tank continues to rise. When the pressure exceeds 70 MPa, the refrigerator and circulation pump are activated to cool the cryogenic propellant inside the tank to absorb the external heat.

[0056] c. Cryogenic propellant delivery:

[0057] The shutoff valve on the throttling delivery pipe is opened to discharge the cryogenic propellant. The openings of the throttling and regulating valves are adjusted to adjust the output flow rate and pressure of the cryogenic propellant. The throttling and decompression process causes a sudden drop in the cryogenic propellant's temperature. The cryogenic propellant then flows into the heat exchange pipes and exchanges heat with the tank walls, recovering cold energy and reducing the power consumption of the entire storage system. The pressure values detected by the first and second pressure sensors, as well as the flow rate detected by the flow sensor, are used to feedback control the openings of the throttling and regulating valves to maintain stable delivery pressure and flow.

[0058] It should be noted that, in this article, relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device comprising the elements.

[0059] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is intended only to illustrate the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A low-loss on-orbit cryogenic propellant storage system for deep space probes, characterized in that: The invention comprises a tank (1) for accommodating cryogenic propellant, wherein the outside of the tank (1) is provided with a heat-insulating layer (2), the tank (1) is connected with a filling pipe (3), a discharge pipe (4) and a cooling assembly (5), the discharge pipe (4) is sequentially connected with a throttling delivery pipe (6), a heat exchange pipe (7) and a supply pipe (8) along the delivery direction of the cryogenic propellant, the throttling delivery pipe (6) and the supply pipe (8) are both provided outside the heat-insulating layer (2), the heat exchange pipe (7) is provided between the tank (1) and the heat-insulating layer (2), the supply pipe (8) is connected to an engine of a deep space probe, the discharge pipe (4) is provided with a first pressure sensor (9), the throttling delivery pipe (6) is provided with a throttle valve (10) and a regulating valve (11), and the supply pipe (8) is provided with a second pressure sensor (12) and a flow sensor (13); After the cryogenic propellant is filled into the tank (1) through the filling pipe (3), as external heat leakage continues to accumulate, the first pressure sensor (9) detects that the pressure in the tank (1) continues to rise. When the value of the first pressure sensor (9) exceeds a preset pressure, the cooling component (5) is activated to cool the cryogenic propellant in the tank (1), thereby absorbing the external heat leakage; wherein, the initial pressure inside the tank (1) after filling is one atmosphere, and the initial stage of the storage phase relies on the passive insulation of the thermal insulation layer (2); When the engine needs to be supplied with cryogenic propellant, the cryogenic propellant is sequentially supplied to the engine through the discharge pipe (4), the throttling delivery pipe (6), the heat exchange pipe (7) and the supply pipe (8), and the supply pressure and supply flow of the cryogenic propellant are adjusted respectively through the throttle valve (10) and the regulating valve (11); wherein, before the engine needs to be supplied with cryogenic propellant, the cryogenic propellant in the tank (1) is in a supercritical state, and the storage temperature is increased by high-pressure storage, thereby reducing the temperature difference and heat leakage between the tank (1) and the outside, thereby reducing the refrigeration capacity requirement of the cooling component (5), and at the same time, the cryogenic propellant inside the tank (1) is in a homogeneous state to ensure the stability of the cryogenic propellant delivery flow and the stable output of the engine, and the preset pressure is higher than the minimum pressure when the cryogenic propellant is in a supercritical state.

2. The system according to claim 1, wherein: The storage tank (1) is made of carbon fiber composite material, and the maximum allowable pressure of the storage tank (1) is greater than the preset pressure.

3. The system according to claim 2, characterized in that A difference between the maximum allowable pressure and the preset pressure is smaller than a difference between the preset pressure and the minimum pressure.

4. The system according to claim 1, wherein: The tank (1) is also connected to a temperature sensor (14), and the temperature sensor (14) is used to detect the real-time temperature of the cryogenic propellant in the tank (1); Based on the pressure detected by the first pressure sensor (9) and the temperature detected by the temperature sensor (14), the current remaining amount of cryogenic propellant in the tank (1) is determined.

5. The system according to claim 1, wherein: The discharge pipe (4) is further connected to an overpressure discharge pipe (15), and a safety valve (16) is provided on the overpressure discharge pipe (15); When the external heat leakage is greater than the cooling capacity of the cooling component (5), the safety valve (16) opens.

6. The system according to claim 5, characterized in that The discharge pipe (4) is further connected to an active discharge pipe (17), and a stop valve (18) is provided on the filling pipe (3), the throttling delivery pipe (6) and the active discharge pipe (17); When filling the cryogenic propellant, the stop valves (18) on the filling pipe (3) and the active discharge pipe (17) are both opened; When the safety valve (16) fails, the stop valve (18) on the active discharge pipe (17) opens; When the engine needs to be supplied with cryogenic propellant, the stop valve (18) on the throttle delivery pipe (6) is opened.

7. The system according to any one of claims 1 to 6, characterized in that The cooling assembly (5) includes a refrigerator (51), a heat exchanger (52) and a circulation pump (53) connected in sequence through pipelines, the refrigerator (51) is arranged outside the thermal insulation layer (2), the heat exchanger (52) and the circulation pump (53) are both arranged inside the storage tank (1) and are both located on the central axis of the storage tank (1), the circulation pump (53) is used to suck the low-temperature propellant from the bottom of the storage tank (1) and send it into the heat exchanger (52), and the refrigerator (51) is used to cool the low-temperature propellant entering the heat exchanger (52) so that the cooled low-temperature refrigerant is discharged horizontally from both sides of the heat exchanger (52).

8. The system according to claim 7, characterized in that The heat exchanger (52) includes a vertically arranged heat exchange inlet (521), two horizontally arranged heat exchange outlets (522), and foam copper (523) respectively connected to the heat exchange inlet (521) and the heat exchange outlets (522). The cold head (511) of the refrigerator (51) is inserted into the foam copper (523). The low-temperature propellant enters the foam copper (523) through the heat exchange inlet (521) and is discharged horizontally through the two heat exchange outlets (522) after heat exchange at the cold head (511).

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