Method for calculating work efficiency in storage tank inflation process and computer program product

Abstract

The invention discloses an acting efficiency calculation method in a storage tank inflation process and a computer program product, which are used for calculating the acting efficiency in the storage tank inflation process, and relate to the field of propellant filling of a spacecraft propulsion system, and the method comprises the following steps: calculating a gas acting condition in the storage tank inflation process to obtain acting Q work of gas on a storage tank; a storage tank shell and internal gas are regarded as a closed system, storage tank heat energy change and gas heat energy change in the storage tank inflation process are calculated, and the sum of the storage tank heat energy change and the gas heat energy change is energy change Q heat of the whole closed system; and according to the energy change Q heat of the whole closed system and the work Q work of the gas on the storage tank, the work efficiency X of the gas is obtained. The work efficiency obtained through calculation is used for a gas supplementing link or a gas cylinder gas adding link of spacecraft propellant filling, and the actual needed filling pressure accurate value in the filling process is obtained.

Description

Technical Field

[0001] This application belongs to the field of propellant filling applications for spacecraft propulsion systems, and relates to a method for calculating the gas work efficiency during the inflation process of spacecraft storage tanks and gas cylinders. It can complete the calculation of the work efficiency by accumulating data during the test process and apply the work efficiency results to the actual propellant filling and inflation links. Background Art

[0002] During the filling process of monopropellant for spacecraft, the general filling process is as follows:

[0003] a. Evacuate the propulsion system and the filling system to create a negative pressure filling environment inside the propulsion system;

[0004] b. Fill the propellant in the storage tank to complete the filling of the propellant in the storage tank;

[0005] c. Fill the pressurizing gas in the storage tank to achieve air cushion gas filling when the propulsion system operates.

[0006] Among them, during the air replenishment step of step c, mainly according to the requirement of the propellant filling pressure, first inflate the storage tank with a pressure higher than the target air cushion pressure value. After 3 to 12 hours of satellite static state and storage tank temperature stabilization and pressure stabilization, then power on the satellite to read the pressure inside the system, and judge whether the pressure meets the requirements according to the storage tank pressure and temperature telemetry. Since filling the air cushion in the storage tank is equivalent to the process of gas doing work on the storage tank, the temperature of the storage tank will increase significantly during the inflation process. Therefore, there are situations where the filling pressure after static state is higher or lower than the target value. If the temperature of the storage tank decreases significantly after static state, it will lead to a lower filling pressure, and it is necessary to reopen the addition and discharge valve on the spacecraft to replenish air to the system, increasing the risk of equipment failure caused by repeated operation of the equipment on the spacecraft. Summary of the Invention

[0007] The technical problem solved by this application is: Overcoming the deficiencies of the prior art, it provides a method for calculating the work efficiency during the inflation process of the storage tank. Through the test data in the ground AIT stage of the spacecraft, the gas work efficiency during the inflation process of the storage tank is obtained. At the same time, the calculated work efficiency can be used for the air replenishment link of spacecraft propellant filling or the gas filling link of gas cylinders to obtain the accurate value of the actual required filling pressure during the filling process.

[0008] During the overall spacecraft large-scale tests or propulsion system tests, the storage tank is inflated. The inflation process is equivalent to the gas doing work on the enclosed space of the storage tank. Therefore, the temperature of the storage tank will increase significantly during the inflation process. The trend and degree of temperature increase reflect the efficiency of the gas doing work. A method for calculating the work efficiency during the inflation process of the storage tank proposed by the present invention calculates the gas work during the inflation process of the storage tank through the actual pressurization of the storage tank during the AIT stage of the spacecraft, monitors the temperature measurement of the storage tank wall, and calculates the actual thermal energy change between the storage tank and the inflation gas. Furthermore, the gas work efficiency during the inflation process of the storage tank is obtained.

[0009] A method for calculating the work efficiency during the inflation process of the storage tank is the first method in China to calculate the work during the inflation process of the storage tank. During the spacecraft propellant filling process, the accurate filling gas pressure value actually required during the filling process can be inversely calculated using the heat conversion rate obtained by this method. There is no relevant literature and data abroad for reference, and it is a completely new design.

[0010] The technical solution provided by this application is as follows:

[0011] A method for calculating the work efficiency during the inflation process of a storage tank includes:

[0012] Calculate the work Q done by the gas during the inflation process of the storage tank to obtain the work done by the gas on the storage tank. 功 ;

[0013] Regard the storage tank shell and the internal gas as a closed system, calculate the thermal energy change of the storage tank and the thermal energy change of the gas during the inflation process of the storage tank. The sum of the thermal energy change of the storage tank and the thermal energy change of the gas is the energy change Q of the entire closed system. 热 ;

[0014] According to the energy change Q of the entire closed system 热 and the work Q done by the gas on the storage tank 功 , obtain the efficiency X of the gas doing work.

[0015] The work Q done by the gas on the storage tank 功 is:

[0016] where V is the volume of the storage tank; during the inflation process of the storage tank, the pressure inside the storage tank rises from P1 to P2.

[0017] The efficiency X of the gas doing work is: X = Q 热 / Q 功 .

[0018] The storage tank is a spherical storage tank. The radius of the inner wall surface of the spherical storage tank is R, and the wall thickness of the storage tank shell is θ. The liquid-end hemisphere of the storage tank has a temperature measurement point 1, and the gas-end hemisphere of the storage tank has a temperature measurement point 2. The distances from the temperature measurement point 1 and the temperature measurement point 2 to the central plane of the storage tank are both the height H. After the inflation process is completed, the temperature rise of the temperature measurement point 1 is ΔT1, and the temperature rise of the temperature measurement point 2 is ΔT2.

[0019] The change in gas thermal energy includes the change in gas thermal energy in the upper hemisphere and the change in gas heat in the lower hemisphere of the storage tank. The change in gas thermal energy in the upper hemisphere of the storage tank is:

[0020]

[0021] Among them, Cp1 is the specific heat capacity of the gas; ρ1 is the gas density at the current pressure after inflation; h is the height of a certain surface from the central plane of the hemisphere, and the range of h is 0 - R.

[0022] The change in gas heat in the lower hemisphere is:

[0023] The change in storage tank thermal energy includes the change in shell heat in the upper hemisphere and the change in shell heat in the lower hemisphere of the storage tank. The change in shell heat in the upper hemisphere of the storage tank is:

[0024]

[0025] Among them, Cp2 is the specific heat capacity of the storage tank shell, and ρ2 is the density of the shell material.

[0026] The change in shell heat in the lower hemisphere is:

[0027]

[0028] In summary, the present application at least includes the following beneficial technical effects:

[0029] (1) In the conventional storage tank inflation process, the efficiency of gas work is not considered, and the storage tank inflation can only be carried out based on experience. The present invention uses an integral method to calculate the increase in the thermal energy of the storage tank and the gas, and accurately calculates the work efficiency of the gas through the gas work principle. The calculation results can be applied to the propellant filling stage of the spacecraft;

[0030] (2) The present invention utilizes the existing propulsion thermal control implementation resources and AIT test data of the spacecraft, and no additional relevant hardware, time and other resources are required during the application process of the present invention. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the calculation model of the present invention. Detailed Embodiment

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the following will further describe in detail the disclosed embodiments of the present invention with reference to the accompanying drawings.

[0033] The embodiments of the present application disclose a method for calculating the work efficiency during the inflation process of a storage tank, as Figure 1 shown, which includes calculating the work done by the gas during the inflation process of the storage tank; regarding the storage tank shell and the internal gas as a model, and calculating the thermal energy change of the storage tank and the gas during the inflation process of the storage tank; the thermal energy change of the model relative to the work done by the gas is the efficiency of the gas doing work.

[0034] Among them, regarding the storage tank shell and the gas in the storage tank as a closed system, the work done by the gas comes from the change in pressure during the gas inflation process; monitoring the temperature change conditions at different positions on the wall surface of the storage tank during the inflation process of the storage tank, and through integral calculation of the thermal energy change trend of the storage tank shell and the internal gas, the thermal energy change situation of the entire model can be obtained.

[0035] Specifically, as Figure 1 shown is a schematic diagram of the calculation model of the present invention. As Figure 1 shown, in this embodiment, a spherical storage tank is taken as an example. The top of the spherical storage tank is connected with a gas addition and discharge valve, and the bottom is connected with a liquid addition and discharge valve. The position of the gas addition and discharge valve is the gas port, and the position of the liquid addition and discharge valve is the liquid port. The inner wall surface radius of the spherical storage tank is R, and the wall thickness of the storage tank shell is θ. The temperature measurement point 1 of the storage tank is located in the liquid end hemisphere of the storage tank, and the temperature measurement point 2 is located in the gas end hemisphere of the storage tank. The distances from the two measurement points to the central plane of the storage tank are both the height H. During the inflation process of the storage tank, the gas addition and discharge valve of the spacecraft is in the closed state. Therefore, the gas end of the storage tank is in a static state. Thus, the storage tank shell and the gas inside the storage tank are regarded as a closed system.

[0036] During the inflation process of the propellant storage tank, the pressure in the storage tank rises from P1 to P2, then the work done by the gas on the storage tank is:

[0037]

[0038] where V is the volume of the storage tank.

[0039] During the inflation process of the propulsion system, the thermal energy change of the closed system comes from the work done by the gas on this closed system. The thermal energy change of the closed system is mainly reflected in the temperature rise of the pressurized gas and the storage tank shell. In this closed system, it is considered that the temperature of the pressurized gas at the same height in the storage tank is the same as the temperature of the storage tank shell.

[0040] After the system is pressurized, the temperature rise of the temperature measurement point 1 of the storage tank is ΔT1, and the temperature rise of the temperature measurement point 2 is ΔT2, then the temperature distribution gradient inside the storage tank is Based on this, the thermal energy change of the gas in the upper hemisphere inside the storage tank is:

[0041]

[0043] Among them, Cp1 is the specific heat capacity of the gas, Δm is the mass of each integration segment, Δt is the temperature rise of each integration segment, and ρ1 is the gas density at the current pressure after the inflation is completed; h is the height of a certain surface from the hemispherical center surface, and the range of h is 0 - R.

[0044] The heat change of the upper hemisphere shell of the storage tank is:

[0045]

[0046] Among them, Cp2 is the specific heat capacity of the storage tank shell, and ρ2 is the density of the shell material.

[0047] The heat change of the gas in the lower hemisphere is:

[0048]

[0049] The heat change of the lower hemisphere shell is:

[0050]

[0051] The heat change of the gas in the storage tank is:

[0052]

[0053] The heat change of the storage tank shell is:

[0054]

[0055] The energy change of the entire closed system is:

[0056] Q 热 = ∑Q i , i = 1, 2, 3, 4 (8)

[0057] According to formulas (1)(8), the work efficiency during the inflation process of the storage tank can be calculated:

[0058] X = Q 热 / Q 功 (9)

[0059] For the test data of the satellite AIT stage of different storage tanks, using P, ΔT1, and ΔT2 at different pressures, the work efficiency at different pressures can be calculated. By fitting the calculated efficiencies, the work efficiency conditions within different pressure ranges can be obtained. For spherical-cylindrical storage tanks, a similar method can be used for integral calculation.

[0060] This embodiment also discloses a computer-readable storage medium, on which computer programs / instructions are stored. When the computer programs / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0061] This embodiment also discloses a computer program product, including computer programs / instructions. When the computer programs / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0062] Contents not detailedly described in the specification of this application belong to the well-known technologies of those skilled in the art.

[0063] The above has described this application in detail in combination with specific implementation manners and exemplary examples. However, these descriptions should not be construed as limiting this application. Those skilled in the art understand that without departing from the spirit and scope of this application, various equivalent substitutions, modifications or improvements can be made to the technical solutions of this application and their implementation manners, and these all fall within the scope of this application. The protection scope of this application is subject to the appended claims.

Claims

1. A calculation method for the work efficiency during the inflation process of a storage tank, characterized in that, Including: Calculate the work done by the gas during the process of filling the storage tank to obtain the work Q done by the gas on the storage tank 功 ; Regarding the tank shell and the internal gas as a closed system, calculate the change in the thermal energy of the tank and the change in the thermal energy of the gas during the tank charging process. The sum of the change in the thermal energy of the tank and the change in the thermal energy of the gas is the energy change Q of the entire closed system 热 ; According to the energy change Q of the entire closed system 热 and the work done by the gas on the storage tank Q 功 , the efficiency X of the work done by the gas is obtained.

2. The calculation method of the work efficiency during the gas filling process of a storage tank according to claim 1, characterized in that, The work Q done by the gas on the storage tank 功 is as follows: Wherein, V is the volume of the storage tank; during the inflation process of the storage tank, the pressure inside the storage tank rises from P1 to P2.

3. The calculation method of the work efficiency during the gas filling process of a storage tank according to claim 1, characterized in that: The efficiency X of the work done by the gas is: X = Q 热 / Q 功 .

4. The calculation method of the work efficiency during the gas filling process of a storage tank according to claim 1, wherein: The storage tank is a spherical storage tank, the inner wall radius of the spherical storage tank is R, and the wall thickness of the storage tank shell is θ; the liquid end hemisphere of the storage tank has a temperature measurement point 1, and the gas end hemisphere of the storage tank has a temperature measurement point 2. The distances from the temperature measurement point 1 and the temperature measurement point 2 to the central plane of the storage tank are both the height H; after the inflation process ends, the temperature rise of the temperature measurement point 1 is ΔT1, and the temperature rise of the temperature measurement point 2 is ΔT2.

5. A calculation method for the work efficiency during the gas filling process of a storage tank according to claim 4, characterized in that: The change in the thermal energy of the gas includes the change in the thermal energy of the gas in the upper hemisphere and the change in the thermal energy of the gas in the lower hemisphere inside the storage tank; The change in the thermal energy of the gas in the upper hemisphere inside the storage tank is: Wherein, Cp1 is the specific heat capacity of the gas; ρ1 is the gas density at the current pressure after inflation; h is the height of a certain horizontal plane from the central plane of the hemisphere, and the range of h is 0 - R.

6. The calculation method of the work efficiency during the gas filling process of a storage tank according to claim 5, wherein: The gas heat change of the lower hemisphere is as follows:

7. A method for calculating the work efficiency during the inflation process of a storage tank according to claim 4, characterized in that: The change in the thermal energy of the storage tank includes the heat change of the shell of the upper hemisphere and the heat change of the shell of the lower hemisphere of the storage tank; The heat change of the shell of the upper hemisphere of the storage tank is: Wherein, Cp2 is the specific heat capacity of the storage tank shell, and ρ2 is the density of the shell material.

8. A calculation method for the work efficiency during the gas filling process of a storage tank according to claim 1, characterized in that: The heat change of the shell of the lower hemisphere is:

9. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 - 8 are implemented.

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