Liquid methane filling system and filling method for rocket launch system

Abstract

The present invention provides a liquid methane filling system for a rocket launch system, comprising a liquid methane storage system, a liquid filling system and a liquid methane emission treatment system connected by pipelines, wherein the liquid methane storage system has a self-pressurizing structure and is connected to the liquid filling system by pipelines, wherein the liquid filling system comprises two mutually redundant filling pipelines, wherein the filling pipeline comprises a supercooling control unit and a filling flow control unit connected by pipelines; a mutual backup valve is provided between the pipelines of the two filling flow control units; and the liquid methane emission treatment system is connected to the filling flow control unit by pipelines. The filling system of the present invention is provided with a redundant configuration, including redundant structures such as two-way filling pipelines, mutual backup valves, a discharge valve group, a four-valve group for hot methane discharge, a three-valve group for hot methane discharge and a three-way valve group for filling and feeding. Moreover, the filling process can be unattended, thereby ensuring the safety of the launch process on site.

Description

Technical Field

[0001] The invention belongs to the technical field of rocket propellant filling, and in particular relates to a liquid methane filling system and a filling method for a rocket launching system. Background Art

[0002] Rocket propellants are usually composed of two chemical substances, fuel and oxidant, which react in the combustion chamber to release heat violently and propel the rocket. Currently, a more common liquid propellant combination is to use hydrazine-50 as the fuel and nitrogen tetroxide as the oxidant. Another combination is to use liquid hydrogen as the fuel and liquid oxygen as the oxidant. This combination is the most promising combination at present, and its combustion efficiency is very high.

[0003] The propellant combination of hydrazine-50 and nitrogen tetroxide has the disadvantages of low combustion efficiency, high material toxicity and high price. Although the propellant combination of liquid hydrogen and liquid oxygen has high combustion efficiency, it has the following disadvantages: (1) Liquid hydrogen has a very low boiling point and its storage temperature at normal pressure is about -252 degrees. It cannot be exposed to air during use, otherwise the frozen oxygen and nitrogen will block the pipeline, increasing the difficulty of storage and operation. (2) Due to the low density of liquid hydrogen, the rocket tank requirements are very large, which increases the difficulty of launch. (3) Due to the ultra-low temperature of hydrogen, it is very easy to evaporate and escape, and the insulation material of the rocket tank is heavier, which increases the launch thrust requirements.

[0004] Due to the above shortcomings of existing propellants, it is not conducive to the development of civil aerospace. Therefore, a combination of liquid methane and liquid oxygen propellants is used to meet the requirements of space launches, which has the following advantages: (1) Liquid methane is used as a combustion agent, which is non-toxic and its combustion products are water and CO2, which is environmentally friendly; (2) Compared with liquid hydrogen, the storage temperature of liquid methane is about -160 degrees, which is higher than the storage temperature of liquid hydrogen, which can greatly reduce the material selection and operation requirements of the filling system. (3) Compared with liquid hydrogen, liquid methane has the advantage of regenerative cooling, which is very suitable for engine regenerative coolant and basically does not produce coking during the combustion process, and there is no carbon deposition phenomenon, so the risk of engine operation failure is reduced.

[0005] The existing methane filling system has the following shortcomings: it cannot meet the requirement of simultaneously filling the first and second stage tanks of the rocket, the corresponding preparation time before the rocket launch is long, and there is a lack of reliable redundant structure; the use of strong electrical equipment may lead to launch failure due to failure of the electrical rotating equipment, and the launch cost is high; there is no pre-cooling and replenishment measure before launch, the fuel reserve in the rocket tank may be insufficient, and the subsequent launch process cannot be reliably guaranteed. Summary of the invention

[0006] In view of this, the present invention aims to provide a liquid methane filling system and filling method for a rocket launch system to meet the launch requirements of civilian or military liquid oxygen and liquid methane combined propellants.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] In a first aspect, the present invention provides a liquid methane filling system for a rocket launch system, comprising a liquid methane storage system, a liquid filling system and a liquid methane emission treatment system connected by pipelines,

[0009] The liquid methane storage system has a self-pressurizing structure and is connected to a liquid filling system via a pipeline. The liquid filling system includes two redundant filling pipelines, and the filling pipeline includes a subcooling control unit and a filling flow control unit connected by pipelines; a mutual valve 22 is provided between the pipelines of the two filling flow control units; the liquid methane emission treatment system is connected to the filling flow control unit via a pipeline.

[0010] Furthermore, the liquid methane storage system includes a liquid methane storage tank and a self-pressurizing instrument, and the liquid methane storage tank and the self-pressurizing instrument form a loop with a first regulating valve through a pipeline; a first temperature acquisition instrument is installed on the liquid methane storage tank, and the first temperature acquisition instrument and the first regulating valve signal are connected to a controller to form a pressure control loop; the top of the liquid methane storage tank is connected to the venting system through a switch valve.

[0011] Furthermore, the subcooling control unit includes a subcooler and a second air bath, an inlet of the subcooler is connected to the liquid methane storage system through a three-way valve; the inlet of the second air bath is connected to the low-temperature cooling source through a second regulating valve, and the outlet of the second air bath is connected to the subcooler through a first switch valve; the outlet of the subcooler is connected to the filling flow control unit through a one-way valve, and the other outlet of the three-way valve is also connected to the filling flow control unit;

[0012] The top of the subcooler is connected to a safe place for venting through the second switch valve and the third regulating valve in turn; the subcooler is provided with a first pressure signal acquisition instrument and a second temperature signal acquisition instrument, and the pipeline connecting the subcooler and the one-way valve is provided with a third temperature signal acquisition instrument, and the first pressure signal acquisition instrument, the second temperature signal acquisition instrument, the third temperature signal acquisition instrument, the second regulating valve, the first switch valve, the second switch valve and the third regulating valve are all connected to the controller by signal; wherein, the controller, the second regulating valve and the third temperature signal acquisition instrument constitute a first subcooling temperature control loop, the controller, the second switch valve and the second temperature signal acquisition instrument constitute a second subcooling temperature control loop, and the controller, the third regulating valve and the first pressure signal acquisition instrument constitute a subcooling safety control loop through signal control.

[0013] Furthermore, the filling flow control unit includes a flow signal acquisition instrument, a fourth regulating valve, a hot methane emission four-valve group, a filling feed three-valve group, a hose and a filter which are connected in sequence through pipelines; the other end of the flow signal acquisition instrument is connected to the three-way valve and the one-way valve; the other end of the filter is connected to the tank of the rocket; a fourth temperature signal acquisition instrument is also provided on the pipeline between the fourth regulating valve and the hot methane emission four-valve group; the flow signal acquisition instrument, the fourth regulating valve and the fourth temperature signal acquisition instrument are all connected to the controller by signal; wherein, the controller, the flow signal acquisition instrument and the fourth regulating valve constitute a filling flow control loop through signal control.

[0014] Furthermore, the liquid methane emission treatment system includes a hot methane emission three-valve group and a hot oxygen collection tank connected by pipelines, the other end of the hot methane emission three-valve group is connected to the filling flow control unit, the hot oxygen collection tank is connected to the safety emission treatment system, and the hot oxygen collection tank and the safety emission treatment system are both connected to the two-stage tanks of the rocket.

[0015] Furthermore, the top of the liquid methane storage tank is connected to two redundant filling pipelines via a discharge valve, and the discharge valve is a redundant structure composed of two switch valves connected in parallel.

[0016] In a second aspect, the present invention provides a filling method for the above-mentioned liquid methane filling system, comprising the following steps:

[0017] (1) Precooling of filling pipelines and rocket tanks

[0018] After the liquid methane storage system achieves self-pressurization, the outlet of the liquid filling system is closed, and the liquid methane emission treatment system is opened to precool the filling pipeline;

[0019] Then close the liquid methane emission treatment system and open the outlet of the liquid filling system to precool the rocket tank;

[0020] (2) High flow filling

[0021] The liquid methane storage system increases pressure, and at the same time opens the liquid filling system, adding a large flow of liquid methane to the rocket's two-stage tanks;

[0022] (3) Thermal methane emissions

[0023] After high-flow filling, the entire filling system is parked for a period of time, the outlet of the liquid filling system is closed, and the liquid methane emission treatment system is opened until the medium temperature in the liquid filling system meets the requirements;

[0024] (4) Add before low flow supercooling shot

[0025] Open the passage between the liquid filling system and the rocket tank, connect it to the cold control unit, supercool the liquid methane to the target temperature through the low-temperature cold source, and then fill it into the rocket tank;

[0026] Among them, during the pre-cooling of the filling pipeline and rocket tank, large-flow filling, hot methane emission and small-flow overcooling pre-launch replenishment, the emitted hot methane is safely treated and then discharged.

[0027] Compared with the prior art, the filling system and filling method of the present invention have the following advantages:

[0028] (1) To ensure the launch requirements, the system is set up with redundancy, including two-way filling pipelines, mutual backup valves, discharge valve group, hot methane discharge four-valve group, hot methane discharge three-valve group and filling and feeding three-way valve group. The two-way filling pipeline can meet the requirements of simultaneous filling of the first and second stage tanks of the rocket while improving efficiency. With the above redundant measures of this system, the launch guarantee rate is as high as 99.9%; and the filling process can be unattended to ensure the safety of the launch process.

[0029] (2) The filling pressure vaporizes its own medium through an air bath to avoid the influence of external media, such as nitrogen pressurization, on the quality of the propellant.

[0030] (3) The use of pre-cooling and replenishing measures before launch can increase the fuel reserve in the rocket tank and ensure the subsequent launch process. At the same time, in order to prevent the solidification of liquid methane and blockage of the filling pipeline, a supercooling temperature safety control loop and a one-way valve 11 are set. When the temperature of the liquid nitrogen in the supercooler is too low, the nitrogen outlet switch valve and the liquid nitrogen inlet switch valve are interlocked and closed.

[0031] (4) The entire refueling system does not use high-voltage equipment. This can avoid launch failures caused by failures of electrical rotating equipment and reduce launch costs.

[0032] (5) The above-mentioned liquid methane filling system can meet the requirements of civil or military launches using a combination of liquid oxygen and liquid methane propellants. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 This is a system structure diagram of the liquid methane filling system described in an embodiment of the present invention.

[0035] Description of reference numerals:

[0036] Liquid methane storage tank 1, first air bath 2, pressure control circuit 3, venting system 4, discharge valve 5, three-way valve 6, subcooler 7, first subcooling temperature control circuit 8, second subcooling temperature control circuit 9, second subcooling safety control circuit 10, one-way valve 11, filling flow control circuit 12, fourth temperature signal acquisition instrument 13, hot methane emission four-valve group 14, filling and feeding three-valve group 15, hose 16, filter 17, hot methane emission three-valve group 18, fire box 19, hot oxygen collection tank 20, flare system 21, mutual backup valve 22, primary storage tank 23, secondary storage tank 24, second air bath 25. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0039] A liquid methane filling system for a rocket launch system, such as Figure 1 As shown, it includes a liquid methane storage system, a liquid filling system and a liquid methane emission treatment system connected by pipelines.

[0040] The liquid methane storage system has a self-pressurizing structure and is connected to a liquid filling system through a pipeline. The liquid filling system includes two mutually redundant filling pipelines, and the filling pipeline includes a subcooling control unit and a filling flow control unit connected by pipelines; a mutual backup valve 22 is provided between the pipelines of the two filling flow control units;

[0041] The liquid methane emission treatment system is connected to the filling flow control unit through a pipeline.

[0042] The liquid methane storage system of this embodiment includes a liquid methane storage tank 1 and a first air bath 2. The liquid methane storage tank 1 and the first air bath 2 form a loop with a first regulating valve through a pipeline. The top of the liquid methane storage tank 1 is connected to a venting system 4 through a switch valve. The venting system 4 is a flare removal system. A first temperature acquisition instrument is installed on the liquid methane storage tank 1. The first temperature acquisition instrument and the first regulating valve signal are connected to a controller to form a pressure control loop 3.

[0043] The first air bath 2 connected to the liquid methane storage tank 1 may also adopt a heat exchanger with other heat sources or add a pump to realize a self-pressurization function.

[0044] The top of the liquid methane storage tank 1 is connected to two mutually redundant filling pipelines through a discharge valve 5, and the filling pipelines include a supercooling control unit, a filling flow control unit and a hot methane discharge unit;

[0045] The subcooling control unit of this embodiment includes a subcooler 7 and a second air bath 25, the top inlet of the subcooler 7 is connected to the discharge valve 5 through a three-way valve 6; the inlet of the second air bath 25 is connected to a liquid nitrogen source through a second regulating valve, and the liquid nitrogen cold source here can also be replaced by other low-temperature cold sources; the outlet of the second air bath 25 is connected to the bottom of the subcooler 7 through a first switch valve; the outlet of the subcooler 7 is connected to the filling flow control unit through a one-way valve 11, and the other outlet of the three-way valve 6 is also connected to the filling flow control unit; the top of the subcooler 7 is connected to a safe place for emptying through the second switch valve and the third regulating valve in turn; the subcooler 7 is provided with a first pressure A signal acquisition instrument and a second temperature signal acquisition instrument, a third temperature signal acquisition instrument is arranged on the pipeline connecting the subcooler 7 and the one-way valve 11, the first pressure signal acquisition instrument, the second temperature signal acquisition instrument, the third temperature signal acquisition instrument, the second regulating valve, the first switch valve, the second switch valve and the third regulating valve are all connected to the controller by signal; wherein, the controller, the second regulating valve and the third temperature signal acquisition instrument constitute a first subcooling temperature control loop 8, the controller, the second switch valve and the second temperature signal acquisition instrument constitute a second subcooling temperature control loop 9, and the controller, the third regulating valve and the first pressure signal acquisition instrument constitute a subcooling safety control loop through signal control.

[0046] The supercooler in this embodiment may be a coil type, plate type or other type of supercooling equipment.

[0047] The filling flow control unit includes a flow signal acquisition instrument, a fourth regulating valve, a hot methane emission four-valve group 14, a filling feed three-valve group 15, a hose 16 and a filter 17 connected in sequence through pipelines, the other end of the flow signal acquisition instrument is connected to the three-way valve 6 and the one-way valve 11, and the other end of the filter 17 is connected to the tank of the rocket 19. Specifically, the filters 17 of the two filling pipelines are respectively connected to the first-stage tank 23 and the second-stage tank 24 of the rocket 19; a fourth temperature signal acquisition instrument 13 is also provided on the pipeline between the fourth regulating valve and the hot methane emission four-valve group 14, and the flow signal acquisition instrument, the fourth regulating valve and the fourth temperature signal acquisition instrument 13 are all connected to the controller by signal; wherein, the controller, the flow signal acquisition instrument and the fourth regulating valve constitute a filling flow control loop 12 through signal control.

[0048] The hot methane emission unit includes a hot methane emission three-valve group 18 and a hot oxygen collecting tank 20 connected by pipelines. The other end of the hot methane emission three-valve group 18 is connected to the filling flow control unit. Specifically, the other end of the hot methane emission three-valve group 18 is connected to the pipeline between the hot methane emission four-valve group 14 and the filling feed three-valve group 15; the hot oxygen collecting tank 20 is connected to the flare system 21, and the hot oxygen collecting tank 20 and the flare system 21 are both connected to the first-stage tank 23 and the second-stage tank 24 of the rocket 19.

[0049] The flare system 21 may adopt other safe emission treatment systems, such as high-altitude emission.

[0050] The discharge valve 5 is a redundant structure composed of two switch valves connected in parallel.

[0051] The filling method of the above-mentioned liquid methane filling system comprises the following steps:

[0052] (1) Precooling of the filling pipeline and the rocket's secondary tank

[0053] After the liquid methane is unloaded into the liquid methane storage tank 1 of the launch plant by a tank truck, the pressure control loop 3 is opened, and the liquid methane enters the first air bath 2. The first air bath 2 uses the ambient atmospheric heat to vaporize the low-temperature liquid methane inside. The vaporized low-temperature natural gas returns to the liquid methane storage tank 1, increasing its system pressure and stabilizing it within the control parameters through the pressure control loop 3.

[0054] ii. When the pressure in the liquid methane storage tank 1 reaches the use requirement, open the discharge valve 5, turn the three-way valve 6 to position A, close the filling feed three-valve group 15, and open the hot methane discharge three-valve group 18 to pre-cool the filling pipeline.

[0055] iii. When the precooling of the filling pipeline meets the use requirements, close the hot methane discharge three-valve group 18, open the filling feed three-valve group 15 to precool the rocket tank. The low-temperature methane gas or liquid generated during the precooling process enters the hot methane collection tank 20, and the methane gas in the hot methane collection tank 20 is safely processed and discharged through the flare system 21.

[0056] (2) High flow filling

[0057] When the precooling of the rocket tank is completed, the pressure of the liquid methane storage tank 1 is increased through the pressure control loop 3, and the filling flow control loop 12 is opened at the same time, and a large flow of liquid methane is added to the two-stage tanks of the rocket.

[0058] (3) Thermal methane emissions

[0059] After high-flow filling, the entire filling system needs to be parked for a period of time. During this period, the liquid methane in the filling system absorbs heat from the environment, and the temperature rises. In order to meet the requirements of space launch, the heat after the temperature rise needs to be discharged. At this time, the filling feed three-valve group 15 is closed, and the hot methane discharge three-valve group 18 is opened to discharge the hot methane in the system until the temperature parameters collected by the fourth temperature signal collection instrument 13 meet the requirements, and then the hot methane discharge three-valve group 18 is closed.

[0060] (4) Add before low flow supercooling shot

[0061] In order to meet the requirements of space launch, supercooling filling should be performed before launch. At this time, the three-valve group 15 for filling and feeding is opened, the three-way valve 6 reaches the B position, the first cooling temperature control loop 8 and the second temperature control loop 9 are opened, and the liquid methane is supercooled to the target temperature through liquid nitrogen and then added to the rocket's secondary tank.

[0062] (5) Methane safety emission treatment system

[0063] During the process of pre-cooling of the filling pipeline and rocket tank, large-flow filling, hot methane discharge and small-flow super-cooling pre-launch replenishment, the discharged hot methane enters the hot methane collection tank 20, and the hot methane gas in the hot methane collection tank 20 and the hot methane gas discharged from the rocket tank enter the flare system 21 for safe treatment before discharge.

[0064] Taking a commercial space launch as an example, the specific implementation method of the liquid methane filling system is as follows:

[0065] (1) Precooling of filling pipelines and rocket tanks

[0066] After the liquid methane is unloaded into the liquid methane storage tank 1 of the launch plant through a tank truck, the pressure control loop 3 is opened, and the liquid methane enters the first air bath. The first air bath uses the ambient atmospheric heat to vaporize the low-temperature liquid methane inside. The vaporized low-temperature natural gas returns to the liquid methane storage tank 1, increasing its system pressure and stabilizing it at 0.3MPaG through the pressure control loop 3.

[0067] ii. Open the discharge valve 5, turn the three-way valve 6 to position A, close the filling feed three-valve group 15, open the hot methane discharge three-valve group 18, open the filling flow control reflux 12 to pre-cool the filling pipeline, and control the flow rate to about 200L / min so that the pre-cooling speed meets the requirements.

[0068] iii. When the fourth temperature signal acquisition instrument 13 of the filling pipeline reaches -150 degrees, close the hot methane discharge three-valve group 18, and open the filling feed three-valve group 15 to pre-cool the rocket tank.

[0069] (2) High flow filling

[0070] When the liquid level inside the rocket tank reaches 10%, the pressure of the liquid methane storage tank 1 is increased to 0.8MPaG through the pressure control circuit 3, and the filling flow control circuit 12 is opened at the same time to control the filling flow to about 2500L / min. A large flow of liquid methane is added to the 1st and 2nd stage tanks of the rocket 19.

[0071] (3) Thermal methane emissions

[0072] After high-flow filling, the entire filling system needs to be parked for a period of time. During this period, the liquid methane in the filling system absorbs ambient heat and heats up. In order to meet the requirements of space launch, the heat after the temperature rises needs to be discharged. At this time, the filling feed three-valve group 15 is closed, and the hot methane discharge three-valve group 18 is opened to discharge the hot methane in the system. When the temperature parameter collected by the fourth temperature signal collection instrument 13 reaches about -160 degrees, the hot methane discharge three-valve group 18 is closed.

[0073] (4) Add before low flow supercooling shot

[0074] In order to meet the requirements of space launch, supercooling filling should be performed before launch. At this time, the three-valve group 15 for filling and feeding is opened, the three-way valve 6 reaches the B position, the first supercooling temperature control loop 8 and the second supercooling temperature control loop 9 are opened, and the liquid methane is supercooled to 103K by liquid nitrogen and then filled into the tank of the rocket 19.

[0075] (5) Methane safety emission treatment system

[0076] During the process of pre-cooling of the filling pipeline and rocket tank, large-flow filling, hot methane discharge and small-flow super-cooling pre-launch replenishment, the discharged hot methane enters the hot methane collection tank 20, and the hot methane gas in the hot methane collection tank 20 and the hot methane gas discharged from the rocket tank enter the flare system 21 for safe treatment before discharge.

[0077] The entire refueling system does not use high-voltage equipment. On the one hand, it avoids launch failures caused by failures of electrical rotating equipment, and on the other hand, it reduces launch costs.

[0078] The filling pressure vaporizes its own medium through an air bath to avoid the influence of external media, such as nitrogen pressurization, on the quality of the propellant.

[0079] The use of pre-cooling and replenishing measures before launch can increase the fuel reserve of the rocket tank and ensure the subsequent launch process. At the same time, in order to prevent the solidification of liquid methane from blocking the filling pipeline, a supercooling temperature safety control loop and a one-way valve 11 are set. When the temperature of liquid nitrogen in the supercooler is too low, the nitrogen outlet switch valve and the liquid nitrogen inlet switch valve are interlocked and closed.

[0080] To ensure the launch requirements, the system is set up with redundancy, including two-way filling pipelines, mutual backup valve 22, discharge valve group 5, hot methane discharge four-valve group 14, hot methane discharge three-valve group 18 and filling three-way valve group 15. The two-way filling pipeline can meet the requirements of simultaneous filling of the first and second stage tanks of the rocket while improving efficiency. With the above redundant measures of this system, the launch guarantee rate is as high as 99.9%.

[0081] The above-mentioned liquid methane filling system can meet the requirements of civil or military liquid oxygen and liquid methane combined propellant launches. It can also realize unattended filling process, ensuring the safety of the launch process.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquid methane filling system for a rocket launch system, characterized in that: The invention comprises a liquid methane storage system, a liquid filling system and a liquid methane emission treatment system connected by pipelines, wherein the liquid methane storage system has a self-pressurizing structure and is connected to the liquid filling system by pipelines, wherein the liquid filling system comprises two mutually redundant filling pipelines, wherein the filling pipelines comprise a supercooling control unit and a filling flow control unit connected by pipelines; a mutual backup valve (22) is provided between the pipelines of the two filling flow control units; and the liquid methane emission treatment system is connected to the filling flow control unit by pipelines; The liquid methane storage system comprises a liquid methane storage tank (1) and a self-pressurizing instrument, wherein the liquid methane storage tank (1) and the self-pressurizing instrument form a loop provided with a first regulating valve through a pipeline; a first temperature acquisition instrument is installed on the liquid methane storage tank (1), and the first temperature acquisition instrument and the first regulating valve signal are connected to a controller to form a pressure control loop (3); the top of the liquid methane storage tank (1) is connected to a venting system (4) through a switch valve; The subcooling control unit comprises a subcooler (7) and a second air bath (25); an inlet of the subcooler (7) is connected to the liquid methane storage system through a three-way valve (6); an inlet of the second air bath (25) is connected to a low-temperature cooling source through a second regulating valve, and an outlet of the second air bath (25) is connected to the subcooler (7) through a first switch valve; an outlet of the subcooler (7) is connected to a filling flow control unit through a one-way valve (11), and another outlet of the three-way valve (6) is also connected to the filling flow control unit; The top of the subcooler (7) is connected to a safe place for venting via a second switch valve and a third regulating valve in sequence; a first pressure signal acquisition instrument and a second temperature signal acquisition instrument are provided on the subcooler (7); a third temperature signal acquisition instrument is provided on a pipeline connecting the subcooler (7) and the one-way valve (11); the first pressure signal acquisition instrument, the second temperature signal acquisition instrument, the third temperature signal acquisition instrument, the second regulating valve, the first switch valve, the second switch valve and the third regulating valve are all connected to a controller by signal; wherein the controller, the second regulating valve and the third temperature signal acquisition instrument form a first subcooling temperature control circuit (8); the controller, the second switch valve and the second temperature signal acquisition instrument form a second subcooling temperature control circuit (9); and the controller, the third regulating valve and the first pressure signal acquisition instrument form a subcooling safety control circuit through signal control.

2. The liquid methane filling system of a rocket launch system according to claim 1, characterized in that: The filling flow control unit comprises a flow signal acquisition instrument, a fourth regulating valve, a hot methane emission four-valve group (14), a filling feed three-valve group (15), a hose (16) and a filter (17) which are connected in sequence through pipelines. The other end of the flow signal acquisition instrument is connected to the three-way valve (6) and the one-way valve (11). The other end of the filter (17) is connected to the tank of the rocket (19). A fourth temperature signal acquisition instrument (13) is also provided on the pipeline between the fourth regulating valve and the hot methane emission four-valve group (14). The flow signal acquisition instrument, the fourth regulating valve and the fourth temperature signal acquisition instrument (13) are all connected to the controller through signals. The controller, the flow signal acquisition instrument and the fourth regulating valve form a filling flow control loop (12) through signal control.

3. The liquid methane filling system of a rocket launch system according to claim 1, characterized in that: The liquid methane emission treatment system comprises a hot methane emission three-valve group (18) and a hot oxygen collection tank (20) connected by pipelines, the other end of the hot methane emission three-valve group (18) is connected to the filling flow control unit, the hot oxygen collection tank (20) is connected to the safety emission treatment system, and the hot oxygen collection tank (20) and the safety emission treatment system are both connected to the two-stage tank of the rocket (19).

4. The liquid methane filling system of a rocket launch system according to claim 1, characterized in that: The top of the liquid methane storage tank (1) is connected to two mutually redundant filling pipelines via a discharge valve (5), and the discharge valve (5) is a redundant structure composed of two switch valves connected in parallel.

5. The filling method of the liquid methane filling system according to any one of claims 1 to 4, characterized in that: The steps include: (1) Precooling of the filling pipeline and rocket tank After the liquid methane storage system achieves self-pressurization, close the outlet of the liquid filling system and open the liquid methane emission treatment system to precool the filling pipeline; then close the liquid methane emission treatment system and open the outlet of the liquid filling system to precool the rocket tank; (2) Filling the liquid methane storage system with a large flow rate to increase the pressure, while opening the liquid filling system, and adding a large flow of liquid methane to the two-stage tanks of the rocket; (3) After the hot methane emission is filled with a large flow rate, the entire filling system is parked for a period of time, the outlet of the liquid filling system is closed, and the liquid methane emission treatment system is opened until the medium temperature in the liquid filling system meets the requirements; (4) Small-flow supercooled pre-launch replenishment opens the passage between the liquid filling system and the rocket tank, connects it to the cold control unit, and supercools the liquid methane to the target temperature through the low-temperature cold source and then fills it into the rocket tank; in the process of pre-cooling of the filling pipeline and rocket tank, large-flow filling, hot methane discharge and small-flow supercooled pre-launch replenishment, the discharged hot methane will be safely treated and then discharged.

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