Multi-tank parallel filling system and method

Abstract

The present invention relates to a multi-tank parallel filling system and method, belonging to the field of rocket propellants. The system of the present invention comprises a filling tank, a filling pipeline, a stop valve, a regulating valve, a flow meter, a liquid level meter and a regulating control system, and the filling pipeline comprises a filling main pipeline and a filling branch pipeline. The present invention adopts a PID algorithm to control the filling amount, couples the data such as the tank liquid level, the flow meter, and the opening of the regulating valve, adjusts the propellant feed amount during the filling process, synchronizes the filling speed of multiple tanks, and finally reaches the specified liquid level at the same time, thereby reducing the propellant consumption during the waiting process.

Description

Technical Field

[0001] The invention belongs to the field of rocket propellants, and in particular relates to a multi-tank parallel filling system and method. Background Art

[0002] With the development of my country's aerospace technology, multi-tank, high-thrust rockets have become the mainstream of space exploration. Liquid hydrogen and liquid oxygen cryogenic propellants have become the most widely used group of propellants for large launch vehicles due to their advantages of non-toxicity, pollution-free, high performance, low cost and high thrust. However, due to the low temperature and large evaporation of cryogenic liquid rockets, it is necessary to complete the precise filling of multiple tanks in the shortest possible time to prevent the evaporation loss of propellant.

[0003] At present, cryogenic propellant refueling is usually completed by one-time refueling + multiple replenishing methods, that is, first use a large flow rate to fill to the specified liquid level, and then replenish according to the evaporation loss of each tank. The operation logic of this refueling method is simple, but the liquid levels of multiple tanks cannot be synchronized, which often leads to large differences between the liquid levels of multiple tanks. The tank that has been filled first needs to wait for the other tanks to be filled before it can be launched. During the waiting process, the tank will heat up severely, which can easily lead to insufficient fuel filling and cause mission failure. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is how to provide a system and method for parallel filling of multiple tanks to solve the problem of asynchronous liquid levels during parallel filling of multiple tanks.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention proposes a multi-tank parallel filling system, which includes a filling tank, a filling pipeline, a stop valve, a regulating valve, a flow meter, a liquid level meter and a regulating control system, and the filling pipeline includes a filling main pipeline and a filling branch pipeline;

[0008] The main filling line is used to connect the filling tank and the filling branch line. A 4# stop valve is set on the main filling line near the first interface of the filling tank to start and stop filling. A storage tank self-pressurization structure is set on the left side of the filling tank body; the fourth interface on the top of the filling tank is connected to the 3# stop valve for pressure relief;

[0009] After the main filling pipeline, multiple filling branch pipelines are connected according to the actual number of filling tanks. Each filling branch pipeline is provided with two parallel filling passages, one filling passage is provided with a stop valve, and the other filling passage is provided with a regulating valve and a flow meter. The flow meter is close to the tank. One end of the two parallel filling passages is connected to the main filling pipeline, and the other end is connected to the tank.

[0010] The tank is provided with a continuous measurement level gauge to monitor the filling level information in real time, including a first level gauge and a second level gauge, the first level gauge is connected to the tank regulating valve through a control line, and the second level gauge is connected to the tank stop valve through a control line;

[0011] The 3# stop valve and the 4# stop valve are both connected to the PLC, and the flow meters of the storage tanks are both connected to the PLC.

[0012] Furthermore, the self-pressurizing structure is composed of a 1# stop valve, a 2# regulating valve and a gasification heat exchange device. The second interface of the filling tank is sequentially connected to the 1# stop valve, the gasification heat exchange device and the 2# regulating valve to the third interface of the filling tank, which is used to adjust the propellant pressure in the filling tank, thereby controlling the filling flow rate.

[0013] Furthermore, both the 1# stop valve and the 2# regulating valve are connected to the PLC.

[0014] Furthermore, the key points on the level meter include L1 and L2, the L1 level is the end level of large-flow filling, and the L2 is the final value level of filling.

[0015] The present invention also provides a method for parallel filling of multiple tanks, the method comprising the following steps:

[0016] S1, during the filling process, when the filling starts, the tank regulating valve and the tank stop valve are opened for large-flow filling. After the filling reaches the specified liquid level L1, the second liquid level meter sends a signal to the tank stop valve to automatically close the tank stop valve, and the system starts to use the tank regulating valve for precise control;

[0017] S2. Using PID algorithm to control filling quantity: The system collects all tank level information measured by the first liquid level meter in real time, calculates the filling flow rate of the tank and the difference between the current tank level and the filling final value level L2, and then obtains the expected remaining time of filling multiple tanks in parallel and the actual remaining time of filling multiple tanks. The PID control valve opening is controlled by taking the expected remaining time of filling multiple tanks in parallel and the actual remaining time of filling multiple tanks as input to obtain a PID control model. The model forms a control deviation according to the fixed value and the actual output value, and the deviation is linearly combined according to the proportion, integration and differentiation to form the tank regulating valve opening control quantity;

[0018] S3. Use the control amount of the regulating valve opening of each tank to control the regulating valve opening of each tank, synchronize the filling speed of multiple tanks, and finally reach the specified liquid level at the same time.

[0019] Furthermore, in step S1, the time for each tank to reach the liquid level L1 is different. When the liquid level is filled to L1, the PID algorithm is used to control the filling amount.

[0020] Furthermore, in step S2, the system collects all tank level information measured by the first liquid level meter in real time, and calculates the tank filling flow rate, including: the system collects all tank level information measured by the first liquid level meter in real time, the system collection frequency is 1s, and calculates the m-th tank filling flow rate M m =L m (t)-L m (t-1), where L m (t) is the liquid level at time t, L m (t-1) is the liquid level at time t-1 of the previous sampling cycle.

[0021] Furthermore, using M m Correct the flow meter and the actual amount of liquid entering the tank is L m =L m0 -L mS , L m0 is the flow meter measurement value, L mS is the evaporation loss value.

[0022] Furthermore, in step S2, obtaining the expected remaining time for parallel filling of multiple tanks and the actual remaining time for filling of multiple tanks includes: the difference between the current liquid level of each tank and the final filling liquid level L2 is a set ΔL=(ΔL1, ΔL2, ..., ΔL m ,…,ΔL n ), where n is the number of tanks to be filled, ΔL m is the difference between the current liquid level of the mth tank and the filling level L2 at the current moment, then the expected remaining time for filling multiple tanks in parallel The actual remaining time for filling multiple tanks is Δt' m The expected filling completion time minus the current time.

[0023] Furthermore, the method for obtaining the tank regulating valve opening control amount in step S2 is:

[0024]

[0025] Where Δt m (-1) is the expected remaining time for filling in the first 1 second, Δt' m (-1) is the actual remaining time of tank filling in the first 1s, L m is the actual amount entering the tank, L m (j) is the liquid level at time j; t is the current time, t0 is the expected filling time, K P is the proportionality coefficient, T i is the integration time constant, T d is the differential coefficient, K P , T i , T dThe value of is obtained through experiments.

[0026] (III) Beneficial effects

[0027] The present invention proposes a multi-tank parallel filling system and method. The present invention couples data such as tank liquid level, flow meter, and regulating valve opening, adjusts the propellant feed amount during the filling process, synchronizes the filling speeds of multiple tanks, and finally reaches the specified liquid level at the same time, thereby reducing the propellant consumption during the waiting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A multi-tank parallel filling system of the present invention;

[0029] Figure 2 It is a schematic diagram of a continuous measurement level meter;

[0030] Figure 3 It is the PID control model. DETAILED DESCRIPTION

[0031] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0032] In order to solve the problem of asynchronous liquid level during parallel filling of multiple tanks, a parallel tank filling system and method is designed to couple data such as tank liquid level, flow meter, and regulating valve opening, adjust the propellant feed amount during the filling process, synchronize the filling speed of multiple tanks, and finally make the time to reach the specified liquid level consistent, thereby reducing the propellant consumption during the waiting process.

[0033] The multi-tank parallel filling system of the present invention comprises a filling tank, a filling pipeline, a stop valve, a regulating valve, a flow meter, a liquid level meter and a regulating control system ( Figure 1 The filling pipeline includes the main filling pipeline and the branch filling pipeline. Figure 1 The dotted line in the figure is the control line, which is controlled by the PLC algorithm to realize valve linkage and signal acquisition processing.

[0034] like Figure 1 As shown, the main filling line is used to connect the filling tank and the filling branch line. A 4# stop valve is set on the main filling line near the first interface of the filling tank for starting and stopping filling. A storage tank self-pressurizing structure is set on the left side of the filling tank body. The self-pressurizing structure consists of a 1# stop valve, a 2# regulating valve and a gasification heat exchange device. The second interface of the filling tank is sequentially connected to the 1# stop valve, the gasification heat exchange device and the 2# regulating valve to the third interface of the filling tank for adjusting the propellant pressure in the filling tank, thereby controlling the filling flow rate; the fourth interface on the top of the filling tank is connected to the 3# stop valve for pressure relief.

[0035] After filling the main pipeline, connect multiple filling branch pipelines according to the actual number of filling tanks. Figure 1 The figure shows that three tanks are filled at the same time, so three filling branch pipelines are designed. Each filling branch pipeline is equipped with two parallel filling passages, one of which is equipped with a stop valve, and the other is equipped with a regulating valve and a flow meter. The flow meter is close to the tank. One end of the two parallel filling passages is connected to the filling main pipeline, and the other end is connected to the tank. Figure 1 As shown, each filling passage of the first tank is provided with a 6# stop valve and a 5# regulating valve respectively, and a flow meter is arranged behind the regulating valve to monitor the filling flow in the pipeline. The structures of the remaining tanks are similar.

[0036] The tank is equipped with a continuous measurement level gauge to monitor the filling level information in real time, including a first level gauge and a second level gauge. The first level gauge is connected to the tank regulating valve through a control line, and the second level gauge is connected to the tank stop valve through a control line. Figure 2 As shown. L1 and L2 are points on the level gauge, L1 is the end level of large flow filling, L2 is the final value level of filling, and L is the current level. Figure 1 As shown, a first liquid level gauge L and a second liquid level gauge L1 are arranged in the first tank to measure the liquid level at the current moment.

[0037] 1# stop valve, 2# regulating valve, 3# stop valve and 4# stop valve are all connected to PLC, and the flow meters of the storage tanks are all connected to PLC.

[0038] The present invention provides a method for parallel filling of multiple tanks, comprising the following steps:

[0039] S1. During the filling process, in order to save filling time, when filling starts, the tank regulating valve and the tank stop valve are opened for large flow filling. After filling to the specified liquid level L1, the second liquid level meter sends a signal to the tank stop valve, automatically closes the tank stop valve, and the system starts to use the tank regulating valve for precise control. Since the positions of the tanks are inconsistent, the time for each tank to reach the L1 liquid level is different. When the liquid level is filled to L1, the PID algorithm is used to control the filling amount.

[0040] S2. Use PID algorithm to control the filling volume: The system collects all tank level information measured by the first liquid level meter in real time. The system collects information at a frequency of 1s and calculates the filling flow rate M of the mth tank. m =L m (t)-L m (t-1), where L m (t) is the liquid level at time t, L m (t-1) is the liquid level at the last sampling period t-1, and then M m The flow meter is corrected because the propellant added to the tank will be lost due to evaporation, so the actual amount L entering the tank m=L m0 -L mS , L m0 is the flow meter measurement value, L mS is the evaporation loss value.

[0041] The difference between the current liquid level of each tank and the final filling level L2 is the set ΔL=(ΔL1, ΔL2, …, ΔL m ,…,ΔL n ), where n is the number of tanks that need to be filled. ΔL m is the difference between the current liquid level of the mth tank and the filling level L2 at the current moment, then the expected remaining time for filling multiple tanks in parallel The actual remaining time for filling multiple tanks is Δt' m (The actual remaining time for filling is the expected filling completion time minus the current time), with Δt' m and Δt m The PID control valve opening is used as input to obtain the PID control model. The model forms a control deviation based on the set value and the actual output value. The deviation is linearly combined according to the proportion, integration and differentiation to form the tank control valve opening control quantity U m (t):

[0042]

[0043] Where Δt m (-1) is the expected remaining time for filling in the first 1 second, Δt' m (-1) is the actual remaining time of tank filling in the first 1s, L m is the actual amount entering the tank, L m (j) is the liquid level at time j; t is the current time, t0 is the expected filling time, K P is the proportionality coefficient, T i is the integration time constant, T d is the differential coefficient, K P , T i , T d The value of is obtained through experiments.

[0044] S3. Use the control amount of the regulating valve opening of each tank to control the regulating valve opening of each tank, synchronize the filling speed of multiple tanks, and finally reach the specified liquid level at the same time.

[0045] The present invention couples data such as tank liquid level, flow meter, regulating valve opening, etc., adjusts the propellant feed amount during the filling process, synchronizes the filling speeds of multiple tanks, and finally reaches the specified liquid level at the same time, thereby reducing the propellant consumption during the waiting process.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-tank parallel filling system, It is characterized in that The system includes a filling tank, a filling pipeline, a tank stop valve, a tank regulating valve, a flow meter, a liquid level meter and a PLC. The filling pipeline includes a filling main pipeline and a filling branch pipeline. The main filling line is used to connect the filling tank and the filling branch line. A 4# stop valve is set on the main filling line near the first interface of the filling tank to start and stop filling. A filling tank self-pressurization structure is set on the left side of the filling tank body; the fourth interface on the top of the filling tank is connected to the 3# stop valve for pressure relief; After the main filling line, multiple filling branch lines are connected according to the actual number of filling tanks. Each filling branch line is provided with two parallel filling passages. One filling passage is provided with a tank shut-off valve, and the other filling passage is provided with a tank regulating valve and a flow meter. The flow meter is close to the tank. One end of the two parallel filling passages is connected to the main filling line, and the other end is connected to the tank. The tank is provided with a continuous measurement level gauge to monitor the filling level information in real time, including a first level gauge and a second level gauge, the first level gauge is connected to the tank regulating valve through a control line, and the second level gauge is connected to the tank stop valve through a control line; The 3# stop valve and the 4# stop valve are both connected to the PLC, and the flow meters of the storage tanks are both connected to the PLC.

2. The multi-tank parallel filling system according to claim 1, It is characterized in that The self-pressurizing structure consists of a 1# stop valve, a 2# regulating valve and a gasification heat exchange device. The 1# stop valve, the gasification heat exchange device and the 2# regulating valve are connected in sequence between the second interface of the filling tank and the third interface of the filling tank to adjust the propellant pressure in the filling tank, thereby controlling the filling flow rate.

3. The multi-tank parallel filling system according to claim 2, It is characterized in that 1# stop valve and 2# regulating valve are both connected to PLC.

4. The multi-tank parallel filling system according to claim 1, It is characterized in that The key points on the level gauge include L1 and L2. The L1 level is the end level of large-flow filling, and the L2 level is the final value level of filling.

5. A method for parallel filling of multiple tanks based on the parallel filling system of multiple tanks according to any one of claims 1 to 4, It is characterized in that The method comprises the following steps: S1, during the filling process, when the filling starts, the tank regulating valve and the tank stop valve are opened for high-flow filling. After the filling reaches the high-flow filling end liquid level L1, the second liquid level meter sends a signal to the tank stop valve to automatically close the tank stop valve, and the system starts to use the tank regulating valve for precise control; S2. Using PID algorithm to control filling quantity: The system collects all tank liquid level information measured by the first liquid level meter in real time, calculates the tank filling flow rate and the difference between the current tank liquid level and the filling final value liquid level L2, and then obtains the expected remaining time of filling multiple tanks in parallel and the actual remaining time of filling multiple tanks. The PID is used to control the opening of the tank regulating valve with the expected remaining time of filling multiple tanks in parallel and the actual remaining time of filling multiple tanks as input to obtain a PID control model. The model forms a control deviation according to the fixed value and the actual output value, and the deviation is linearly combined according to the proportion, integration and differentiation to form the tank regulating valve opening control amount; S 3. Use the tank regulating valve opening control amount of each tank to control the tank regulating valve opening of each tank, synchronize the filling speeds of multiple tanks, and finally reach the filling final value liquid level L2 at the same time.

6. The multi-tank parallel filling method according to claim 5, It is characterized in that In step S1, the time for each tank to reach the liquid level L1 is different. When the liquid level is filled to L1, the PID algorithm is used to control the filling amount.

7. The multi-tank parallel filling method according to claim 5, It is characterized in that In step S2, the system collects all tank level information measured by the first liquid level meter in real time, and calculates the tank filling flow rate, including: the system collects all tank level information measured by the first liquid level meter in real time, the system collection frequency is 1s, and calculates the m-th tank filling flow rate M m =L m (t)-L m (t-1), where L m (t) is the liquid level at time t, L m (t-1) is the liquid level at time t-1 of the previous sampling cycle.

8. The multi-tank parallel filling method according to claim 7, It is characterized in that The actual amount entering the tank is L m =L m0 -L mS , L m0 is the flow meter measurement value, L mS is the evaporation loss value.

9. The multi-tank parallel filling method according to claim 8, It is characterized in that In step S2, obtaining the expected remaining time for parallel filling of multiple tanks and the actual remaining time for filling of multiple tanks includes: the difference between the current liquid level of each tank and the final filling liquid level L2 is the set ΔL={ΔL 1 , ΔL 2 , ..., ΔL m , ..., ΔL n }, where n is the number of tanks that need to be filled, ΔL m is the difference between the current liquid level of the mth tank at the current moment and the final filling value level L2, then the expected remaining time for filling multiple tanks in parallel The actual remaining time for filling multiple tanks is Δt′ m The expected filling completion time minus the current time.

10. The multi-tank parallel filling method according to claim 9, It is characterized in that The method for obtaining the tank regulating valve opening control amount in step S2 is: Where Δt m (-1) is the expected remaining time for refueling in the first 1 second, Δt′ m (-1) is the actual remaining time of tank filling in the first 1s, L m is the actual amount entering the tank, L m (j) is the liquid level at time j; t is the current time, t 0 is the expected refilling time, K P is the proportionality coefficient, T i is the integration time constant, T d is the differential coefficient, K P , T i , T d The value of is obtained through experiments.

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