Liquid oxygen propellant filling system and pre-cooling pump starting method thereof

Abstract

The invention relates to the technical field of low-temperature propellant filling, in particular to a liquid oxygen propellant filling system and a pre-cooling pump starting method thereof, and provides the liquid oxygen propellant filling system which cancels a filling bypass, reduces the bypass leakage risk, enables the whole filling system to be more simplified, and improves the filling efficiency. The invention further provides a pre-cooling pump starting method of the liquid oxygen propellant filling system. The pre-cooling pump starting method comprises the following steps that the pipeline is pre-cooled, the filling valve at the liquid oxygen storage tank end is opened, the filling valve at the rocket liquid oxygen storage tank end is closed, the exhaust valve is opened, liquid oxygen flows through the pipeline, and the pipeline is pre-cooled. Pre-cooling the storage tank, namely pre-cooling the storage tank after the pipeline is pre-cooled; starting the pump for pre-cooling, starting the liquid oxygen filling pump at low frequency, and gradually increasing the frequency of the liquid oxygen filling pump. Storage tank filling is carried out through the high-position pump and the low-position pump, liquid oxygen does not need to be extruded into the storage tank through bypass pressure increasing, the precooling flow process does not need to be interrupted, procedure conversion of liquid oxygen precooling and large-flow filling is not needed, the operation difficulty is reduced, and the filling time is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of cryogenic propellant filling, and in particular to a liquid oxygen propellant filling system and a pre-cooling pump starting method thereof. Background Art

[0002] Liquid oxygen propellant is the current mainstream cryogenic rocket propellant. It has the advantages of being non-toxic, pollution-free, low-cost, and high specific impulse. It is widely used in aerospace and rocket technology.

[0003] In the prior art, liquid oxygen refueling adopts two power modes: air pillow extrusion and liquid oxygen pump. Air pillow extrusion is used in the pre-cooling stage. In order to pressurize liquid oxygen into a high-altitude storage tank, the ground liquid oxygen refueling tank needs to be increased to a higher pressure, which exceeds the upper limit of the working pressure before the liquid oxygen pump, which is easy to cause leakage of cryogenic propellant. At this time, the liquid oxygen pump should be isolated from the pipeline and enter a slow warming state. Large-flow refueling adopts liquid oxygen pump refueling, which requires interrupting the pre-cooling flow process, first depressurizing the storage tank, and then discharging pre-cooling and state preparation of the liquid oxygen pump. The process conversion between liquid oxygen pre-cooling and large-flow refueling requires additional operations and state changes such as tank pressurization and depressurization, liquid oxygen pump isolation and communication, pump cooling, warming and re-cooling, which greatly increases the difficulty of operation and refueling time. Summary of the invention

[0004] The present invention provides a liquid oxygen propellant filling system, which does not need to increase the pressure through a bypass to squeeze the liquid oxygen into a tank, reduces the risk of bypass leakage, and does not need to interrupt the precooling flow process during filling.

[0005] The present invention provides the following technical solutions:

[0006] A liquid oxygen propellant filling system, comprising

[0007] Liquid oxygen storage tank, used to store liquid oxygen;

[0008] The high-level filling pipeline connects the liquid oxygen storage tank and the rocket high-level tank;

[0009] The low-level filling pipeline connects the liquid oxygen storage tank and the rocket's low-level tank.

[0010] Furthermore, the high-position filling pipeline is connected in parallel with the low-position filling pipeline, and a liquid oxygen storage tank end filling valve is provided on the pipeline connecting the liquid oxygen storage tank with the high-position filling pipeline and the low-position filling pipeline.

[0011] Further, the high-level filling pipeline is sequentially provided with a third valve, a high-level liquid oxygen filling pump, a fourth valve and a high-level liquid oxygen filling valve, a high-level filling exhaust pipeline is provided between the fourth valve and the high-level liquid oxygen filling valve, and a high-level filling exhaust valve is provided on the high-level filling exhaust pipeline;

[0012] The low-level filling pipeline is sequentially provided with a seventh valve, a low-level liquid oxygen filling pump, an eighth valve, and a low-level filling exhaust pipeline is provided between the eighth valve and the low-level liquid oxygen filling valve, and a low-level filling exhaust valve is provided on the low-level filling exhaust pipeline.

[0013] Furthermore, the liquid oxygen storage tank, the rocket high-level storage tank and the low-level filling pipeline are all provided with pressure, temperature and liquid level monitoring devices, and the liquid oxygen storage tank is also provided with a vaporizer.

[0014] Furthermore, it also includes a high-level pump pressure relief discharge pipeline and a low-level pump pressure relief discharge pipeline; one end of the high-level pump pressure relief discharge pipeline is arranged between the high-level liquid oxygen filling valve and the fourth valve, and the other end is arranged behind the high-level filling and exhaust valve of the high-level filling and exhaust pipeline, and the high-level pump pressure relief discharge valve is arranged on the high-level pump pressure relief discharge pipeline; one end of the low-level pump pressure relief discharge pipeline is arranged between the low-level liquid oxygen filling valve and the eighth valve, and the other end is arranged behind the low-level filling and exhaust valve of the low-level filling and exhaust pipeline, and the low-level pump pressure relief discharge valve is arranged on the low-level pump pressure relief discharge pipeline.

[0015] The present invention also provides a pre-cooling pump starting method for a liquid oxygen propellant filling system, comprising the following steps:

[0016] To pre-cool the pipeline, open the filling valve at the liquid oxygen storage tank end, close the filling valve at the rocket liquid oxygen storage tank end, and open the exhaust valve to allow liquid oxygen to flow through the pipeline to pre-cool the pipeline;

[0017] After the tank is precooled and the pipeline is precooled, the tank is precooled;

[0018] Start the pump for pre-cooling, start the liquid oxygen filling pump at a low frequency, and gradually increase the frequency of the liquid oxygen filling pump.

[0019] Furthermore, the liquid oxygen propellant filling system includes a high-level filling pipeline and a low-level filling pipeline, which are respectively used to fill the rocket high-level tank and the rocket low-level tank. In the pipeline precooling step, the filling valve at the liquid oxygen storage tank end is opened, the filling valve at the rocket high-level tank end and the filling valve at the rocket low-level tank end are closed, the third valve, the fourth valve and the high-level filling exhaust valve of the high-level filling pipeline are opened, the seventh valve, the eighth valve and the low-level filling exhaust valve of the low-level filling pipeline are opened, the high-level pump pressure relief discharge valve and the low-level pump pressure relief discharge valve are closed, so that liquid oxygen flows through the pipeline to precool the pipeline.

[0020] Furthermore, after the pipeline is precooled to the temperature before the high-level liquid oxygen filling valve and the low-level liquid oxygen filling valve being lower than 40K, the high-level liquid oxygen filling valve at the high-level tank end of the rocket and the low-level liquid oxygen filling valve at the low-level tank end of the rocket are opened to allow liquid oxygen to be injected into the tanks, and the tank precooling begins.

[0021] Furthermore, in the pump pre-cooling step, when the liquid oxygen in the low-level tank of the rocket accumulates to a preset liquid level, the low-level liquid oxygen filling pump is started at a low frequency, and the operating frequency of the low-level liquid oxygen filling pump is gradually increased to the preset frequency; 10 seconds after the low-level liquid oxygen filling pump is started, the high-level liquid oxygen filling pump is started at a low frequency, and the operating frequency of the high-level liquid oxygen filling pump is gradually increased to the preset frequency.

[0022] Furthermore, the operating frequency of the low-level liquid oxygen filling pump and the high-level liquid oxygen filling pump is gradually increased at a rate of 5HZ per second.

[0023] The beneficial effects of the present invention are as follows: a liquid oxygen propellant filling system of the present invention eliminates the filling bypass, reduces the risk of bypass leakage, and simplifies the entire filling system. The pre-cooling pump starting method of the liquid oxygen propellant filling system provided by the present invention fills the tank through a high-level pump and a low-level pump. There is no need to increase the pressure through a bypass to squeeze the liquid oxygen into the tank, and there is no need to interrupt the pre-cooling flow process. There is no need to convert the process of liquid oxygen pre-cooling and large-flow filling, which reduces the difficulty of operation and the filling time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part 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 drawings:

[0025] Figure 1 It is a schematic structural diagram of the liquid oxygen propellant filling system of the present invention. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0027] See also Figure 1 The liquid oxygen propellant filling system of this embodiment includes:

[0028] The liquid oxygen storage tank 2 is used to store liquid oxygen; a pressure, temperature, liquid level and other monitoring devices 1 are arranged inside the liquid oxygen storage tank, and a vaporizer 3 is also arranged on the liquid oxygen storage tank.

[0029] A high-level filling pipeline connects the liquid oxygen storage tank 2 and the rocket high-level storage tank 6, including a third valve 3#, a high-level liquid oxygen filling pump 5, a fourth valve 4# and a high-level liquid oxygen filling valve 10# connected in sequence, a high-level filling exhaust pipeline is arranged between the fourth valve 4# and the 10# high-level liquid oxygen filling valve 10#, and a high-level filling exhaust valve 12# is arranged on the high-level filling exhaust pipeline; it also includes a high-level pump pressure relief discharge pipeline, one end of the high-level pump pressure relief discharge pipeline is arranged between the high-level liquid oxygen filling valve 10# and the fourth valve 4#, and the other end is arranged after the high-level filling exhaust valve 12# of the high-level filling exhaust pipeline, and a high-level pump pressure relief discharge valve 5# is arranged on the high-level pump pressure relief discharge pipeline;

[0030] The low-level filling pipeline connects the liquid oxygen storage tank 2 and the rocket low-level storage tank 7, and includes the seventh valve 7#, the low-level liquid oxygen filling pump 4, the eighth valve 8# and the low-level liquid oxygen filling valve 11#, which are connected in sequence. A low-level filling exhaust pipeline is arranged between the eighth valve 8# and the low-level liquid oxygen filling valve 11#, and a low-level filling exhaust valve 13# is arranged on the low-level filling exhaust pipeline. It also includes a low-level pump pressure relief discharge pipeline, one end of which is arranged between the low-level liquid oxygen filling valve 11# and the eighth valve 8#, and the other end is arranged after the low-level filling exhaust valve 13# of the low-level filling exhaust pipeline, and a low-level pump pressure relief discharge valve 9# is arranged on the low-level pump pressure relief discharge pipeline.

[0031] High-level pump pressure relief valve 5# and low-level pump pressure relief valve 9# are usually closed and are mainly used during parking. The liquid oxygen in the pump pipeline absorbs heat and vaporizes during parking, causing the pipeline temperature to rise. Pressure can be relieved through these two valves to prevent excessive pressure from causing overpressure in the pump area.

[0032] The high-position filling pipeline is connected in parallel with the low-position filling pipeline, and a liquid oxygen storage tank end filling valve 1# is arranged on the pipeline connecting the liquid oxygen storage tank with the high-position filling pipeline and the low-position filling pipeline.

[0033] The liquid oxygen storage tank 2, the rocket high-level storage tank 6 and the low-level filling pipeline are all provided with pressure, temperature and liquid level monitoring devices.

[0034] The pre-cooling pump starting method of the liquid oxygen propellant filling system comprises the following steps:

[0035] Precool the pipeline. In the initial stage of precooling, the temperature of liquid oxygen is high and the boiling volume is large, which can easily cause overpressure in the tank. Close the high-level liquid oxygen filling valve 10# and the low-level liquid oxygen filling valve 11# at the rocket liquid oxygen tank end, open the filling valve 1# at the liquid oxygen storage tank end, and use the third valve 3#, the fourth valve 4#, the seventh valve 7#, the eighth valve 8#, and open the high-level filling exhaust valve 12# and the low-level filling exhaust valve 13# to discharge oxygen, so that liquid oxygen flows through the pipeline to precool the pipeline.

[0036] Precooling of the tank, after the pipeline is precooled until the valve temperature before the high-level liquid oxygen filling valve and the low-level liquid oxygen filling valve is lower than 40K (generally about 20 minutes), the high-level liquid oxygen filling valve 10# at the high-level tank end of the rocket and the low-level liquid oxygen filling valve 11# at the low-level tank end of the rocket are opened to inject liquid oxygen into the high-level tank and the low-level tank of the rocket, and start precooling of the tank; after the tank is precooled for 5 minutes, the liquid oxygen is allowed to flow through the high-level liquid oxygen filling pump 5 and the low-level liquid oxygen filling pump 4 for pump precooling. During the tank precooling process, if the high-level tank and the low-level tank of the rocket are overpressured, the corresponding high-level filling exhaust valve 12# or low-level filling exhaust valve 13# is opened.

[0037] Start the pump for precooling. Liquid oxygen will also accumulate in the tank during the precooling process. When the liquid oxygen in the low-level tank of the rocket accumulates to the preset liquid level, start the low-level liquid oxygen filling pump at a low frequency of 10HZ, and gradually increase the operating frequency of the low-level liquid oxygen filling pump at a rate of 5HZ every 5 seconds until it reaches the preset frequency or rated frequency, which is generally 40-50HZ; 10 seconds after the low-level liquid oxygen filling pump is started, start the high-level liquid oxygen filling pump at a low frequency of 10HZ, and run it at a low frequency of 10HZ for 5s. At this time, the high-level tank is located at a higher position and the precooling is insufficient. Overpressure may be caused by excessive pump frequency increase. Therefore, during the frequency increase process, always pay attention to the tank pressure. If the pressure exceeds the upper limit, stop the frequency increase, open the high-level filling exhaust valve 12, and discharge it until the pressure drops to a safe range. Then close the exhaust valve and continue to increase the frequency. Repeat this cycle until the high-level pump reaches the preset frequency or rated frequency, which is generally 40-50HZ.

[0038] Those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A liquid oxygen propellant filling system, characterized in that: include Liquid oxygen storage tank, used to store liquid oxygen; The high-level filling pipeline connects the liquid oxygen storage tank and the rocket high-level tank; The low-level filling pipeline connects the liquid oxygen storage tank and the rocket's low-level tank.

2. The liquid oxygen propellant filling system according to claim 1, characterized in that: The high-position filling pipeline is connected in parallel with the low-position filling pipeline, and a liquid oxygen storage tank end filling valve is arranged on the pipeline connecting the liquid oxygen storage tank with the high-position filling pipeline and the low-position filling pipeline.

3. The liquid oxygen propellant filling system according to claim 2, characterized in that: The high-level filling pipeline is provided with a third valve, a high-level liquid oxygen filling pump, a fourth valve and a high-level liquid oxygen filling valve in sequence, a high-level filling exhaust pipeline is provided between the fourth valve and the high-level liquid oxygen filling valve, and a high-level filling exhaust valve is provided on the high-level filling exhaust pipeline; The low-level filling pipeline is sequentially provided with a seventh valve, a low-level liquid oxygen filling pump, an eighth valve, and a low-level filling exhaust pipeline is provided between the eighth valve and the low-level liquid oxygen filling valve, and a low-level filling exhaust valve is provided on the low-level filling exhaust pipeline.

4. The liquid oxygen propellant filling system according to claim 3, characterized in that: The liquid oxygen storage tank, the rocket high-level storage tank and the low-level filling pipeline are all provided with pressure, temperature and liquid level monitoring devices, and the liquid oxygen storage tank is also provided with a vaporizer.

5. The liquid oxygen propellant filling system according to any one of claims 1 to 4, characterized in that: It also includes a high-level pump pressure relief discharge pipeline and a low-level pump pressure relief discharge pipeline; one end of the high-level pump pressure relief discharge pipeline is arranged between the high-level liquid oxygen filling valve and the fourth valve, and the other end is arranged behind the high-level filling and exhaust valve of the high-level filling and exhaust pipeline, and a high-level pump pressure relief discharge valve is arranged on the high-level pump pressure relief discharge pipeline; one end of the low-level pump pressure relief discharge pipeline is arranged between the low-level liquid oxygen filling valve and the eighth valve, and the other end is arranged behind the low-level filling and exhaust valve of the low-level filling and exhaust pipeline, and a low-level pump pressure relief discharge valve is arranged on the low-level pump pressure relief discharge pipeline.

6. A pre-cooling pump start method for a liquid oxygen propellant filling system, characterized in that: The steps include: To pre-cool the pipeline, open the filling valve at the liquid oxygen storage tank end, close the filling valve at the rocket liquid oxygen storage tank end, and open the exhaust valve to allow liquid oxygen to flow through the pipeline to pre-cool the pipeline; After the tank is precooled and the pipeline is precooled, the tank is precooled; Start the pump for pre-cooling, start the liquid oxygen filling pump at a low frequency, and gradually increase the frequency of the liquid oxygen filling pump.

7. The method according to claim 6, characterized in that The liquid oxygen propellant filling system includes a high-level filling pipeline and a low-level filling pipeline, which are respectively used to fill the rocket high-level tank and the rocket low-level tank. In the pipeline precooling step, the filling valve at the liquid oxygen storage tank end is opened, the filling valve at the rocket high-level tank end and the filling valve at the rocket low-level tank end are closed, the third valve, the fourth valve and the high-level filling exhaust valve of the high-level filling pipeline are opened, the seventh valve, the eighth valve and the low-level filling exhaust valve of the low-level filling pipeline are opened, the high-level pump pressure relief discharge valve and the low-level pump pressure relief discharge valve are closed, so that liquid oxygen flows through the pipeline to precool the pipeline.

8. The method according to claim 7, characterized in that After the pipeline is precooled to the temperature before the high-level liquid oxygen filling valve and the low-level liquid oxygen filling valve is lower than 40K, open the high-level liquid oxygen filling valve at the high-level tank end of the rocket and the low-level liquid oxygen filling valve at the low-level tank end of the rocket to inject liquid oxygen into the tank and start tank precooling.

9. The method according to claim 8, characterized in that During the pump pre-cooling step, when the liquid oxygen in the rocket's low-level tank accumulates to the preset liquid level, the low-level liquid oxygen filling pump is started at a low frequency, and the operating frequency of the low-level liquid oxygen filling pump is gradually increased to the preset frequency; 10 seconds after the low-level liquid oxygen filling pump is started, the high-level liquid oxygen filling pump is started at a low frequency, and the operating frequency of the high-level liquid oxygen filling pump is gradually increased to the preset frequency.

10. The method according to any one of claims 7 to 9, characterized in that Gradually increase the operating frequency of the low-level liquid oxygen filling pump and the high-level liquid oxygen filling pump at a rate of 5HZ per second.

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