Trans-medium vehicle power system water entry process control method

Abstract

This invention discloses a water entry control method for a cross-medium vehicle propulsion system, comprising the following steps: establishing a top-level system architecture model of the cross-medium vehicle's air-to-water propulsion system; based on the top-level system architecture model, establishing a combustion chamber model, a turbine output torque equation, and a load model of the air-to-water propulsion system; introducing a custom function into the control logic module to simulate the predetermined timing actions of the engine and to achieve adaptive adjustment of the fuel pump angle based on system speed feedback; establishing a dynamic simulation model, configuring the initial boundary conditions and time step of the simulation calculation, and performing dynamic simulation on the top-level system architecture model, each sub-model, and the control logic module to generate a full-condition dynamic simulation model of the air-to-water propulsion system. This invention's water entry control method for a cross-medium vehicle propulsion system solves the problems of runaway and engine shutdown caused by the rapid coupling of multiple physical quantities during water entry.

Description

Technical Field

[0001] This invention belongs to the field of cross-medium vehicle control technology, specifically relating to a control method for the water entry process of a cross-medium vehicle propulsion system. Background Technology

[0002] Cross-medium vehicles can autonomously switch between operating in air and water, two media with different densities, and can cross the medium interface multiple times. The air-to-water propulsion system is one of the core components of a cross-medium vehicle, directly affecting its performance. Unlike the control methods of conventional single-medium vehicles, after the air-powered propulsion system enters the water entry preparation phase, the air intake closes, and the compressor and turbine are disconnected. During water entry, the axial-flow propulsion pump connects to the turbine before contact with the water, and the air-powered propulsion system switches to an underwater propulsion system. The system load changes significantly during these two phases, which may cause a surge in turbine speed and a sudden drop in combustion chamber pressure, leading to runaway and engine shutdown phenomena.

[0003] The water entry process of a cross-medium vehicle's propulsion system can be divided into three stages: compressor disconnection (0-2s), system idling (2-4s), and axial propulsion pump activation (after 4s). During the water entry preparation process, the air intake is closed, and the compressor and turbine are disconnected. Since the compressor is the main load of the propulsion system at this time, its disconnection leads to a significant reduction in system load, causing a surge in turbine speed and consequently, an increase in combustion chamber pressure, potentially damaging both the turbine and combustion chamber. After 4s, the axial propulsion pump reconnects to the turbine. As the vehicle becomes wet, the internal flow channel at the stern gradually fills with seawater, increasing the torque of the axial propulsion pump within the channel, making it the main load of the propulsion system at this point. This increased system load reduces turbine speed, leading to a decrease in combustion chamber pressure. At this stage, the fuel pump displacement needs to be adjusted to increase combustion chamber pressure and prevent it from falling below the set minimum pressure. During water entry, parameters such as system load, turbine speed, and combustion chamber pressure undergo significant changes, with each system parameter constantly changing and coupled with the others. Therefore, it is urgent to regulate the turbine parameters in these two stages to prevent runaway and stalling.

[0004] Currently, the field of turbomachinery has conducted extensive research on closed-loop control of turbine engine speed based on modeling and simulation methods. These studies primarily focus on the nonlinearity and wide-range speed changes and depth variations of turbine engine systems, and most are conducted in a single medium. Unlike closed-loop control of turbine engines in a single medium, the load on the propulsion system of a cross-medium vehicle is highly transient during water entry preparation and entry. Furthermore, the pressure in the combustion chamber is constantly changing and coupled with the turbine speed and system load torque. Accurate control of the turbine speed and combustion chamber pressure requires considering the coupling of multiple physical quantities in the control strategy. Existing closed-loop control methods for turbine engines in a single medium are not suitable for solving the water entry process of cross-medium vehicles, as they do not address the system load changes during water entry, resulting in significant deviations from actual operating conditions. The correctness of the control strategy for the two rapidly changing load phases—compressor cutoff and axial propulsion pump startup—is crucial for the successful water entry of the cross-medium vehicle. Therefore, a high-precision, low-computational-cost dynamic simulation method is needed to simulate the water entry process of a cross-medium vehicle to ensure the stable operation of the turbine and combustion chamber during water entry. Summary of the Invention

[0005] The purpose of this invention is to provide a control method for the water entry process of a cross-medium vehicle propulsion system, which solves the problems of runaway and engine shutdown caused by the rapid coupling of multiple physical quantities during the water entry process.

[0006] The technical solution adopted in this invention is a method for controlling the water entry process of a cross-medium vehicle propulsion system, comprising the following:

[0007] S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system respectively; S3. Construct a control logic module. The control logic module introduces custom functions to simulate the predetermined timing actions of the engine and realize the adaptive adjustment of the fuel pump angle based on the system speed feedback. S4. Establish a dynamic simulation model, configure the initial boundary conditions and time step of the simulation calculation, and perform dynamic simulation on the top-level system architecture model, each sub-model in S2 and the control logic module to generate a full-condition dynamic simulation model of the air-water propulsion system.

[0008] The invention is further characterized by: The specific process of S1 is as follows: The air-water propulsion system is divided into two parts: an air propulsion system and an underwater propulsion system. The air propulsion system and the underwater propulsion system share a combustion chamber and a turbine, and both use underwater fuel. Its transmission system should also have a clutch function, which changes the power transmission path through an electromagnetic clutch, so that the connection between the main engine and the compressor can be disconnected during air deceleration and landing and underwater operation. During air navigation, the turbine drives the compressor for jet propulsion; during underwater navigation, the turbine drives the axial flow propulsion pump for water jet propulsion.

[0009] S2 includes S2.1, and the specific process of S2.1 is as follows: Based on dynamic system simulation software, a combustion chamber model is established according to the actual working process of the combustion chamber, and the combustion chamber pressure is calculated by formulas (1)-(6):

[0010]

[0011]

[0012]

[0013]

[0014]

[0015] In the formula, The amount of gas produced per unit time. Let k be the turbine speed at time k. Let k be the fuel pump displacement at time k. The flow rate of the gas ejected from the nozzle. This represents the area of ​​the nozzle throat. For specific heat ratio, The gas constant is The combustion chamber temperature, Let K be the combustion chamber pressure at time k. This represents the change in gas mass flow rate. Let the mass of the gas at time k+1 be... Let K be the mass of the gas at time k. For simulating step size, This represents the change in combustion chamber pressure. The combustion chamber temperature, The free volume of the combustion chamber. Let k be the combustion chamber pressure at time k+1.

[0016] S2 also includes S2.2, the specific process of which is as follows: Based on dynamic system simulation software, the turbine output torque equation and the load model of the air-water propulsion system are established according to the dynamic torque equation. The turbine speed is calculated by formulas (7)-(12):

[0017]

[0018]

[0019]

[0020]

[0021]

[0022] (13)

[0023] In the formula, To absorb torque for the lubricating oil pump, It is a positive constant. To absorb torque for the generator, It is a positive constant. To absorb torque for the fuel pump, It is a positive constant. Let k be the fuel pump displacement at time k. Let k be the combustion chamber pressure at time k. For the load torque of the axial flow propulsion pump, It is a positive constant. This is the load torque of the compressor. and It is a positive constant. For the resistance torque of the power system, To provide torque for the turbine output, The loss coefficient, The absolute velocity of the gas entering the turbine blades. The angle between the absolute velocity of the inlet and the plane of the wheel. The circumferential velocity of the turbine wheel. The velocity factor of the moving blade cascade, For the relative speed of imports, The relative velocity angle at the exit. Where is the radius of the turbine disk. Let k+1 be the turbine speed. This is the reduced moment of inertia of the underwater vehicle's propulsion system.

[0024] S3 includes S3.1, and its specific process is as follows: The engine timing sequence is designed as follows: First, from 0-2 seconds, the power system is an air-powered propulsion system, with the load consisting of the compressor and various auxiliary engines. The turbine speed is maintained at the air cruise design speed. At 2 seconds, the compressor is disconnected in the air, and the power system load consists of the loads of the various auxiliary engines. The system idles for 2 seconds, and the turbine speed is the system idle speed. At 4 seconds, before the vehicle enters the water, the axial propulsion pump is connected to the turbine, and the power system becomes an underwater propulsion system. The power system load consists of the axial propulsion pump and various auxiliary engines, and the turbine speed is maintained at the underwater cruise design speed. When designing the engine timing, the high-speed clutch is generally connected to the compressor, and the low-speed clutch is usually connected to the axial propulsion pump. When disconnecting the compressor and connecting the axial propulsion pump, the solenoid valve clutch engagement time needs to be considered in advance, as does its power load during solenoid valve clutch operation.

[0025] S3 includes S3.2, and its specific process is as follows: The fuel pump is controlled according to the actual variable displacement fuel pump. The specific working process is as follows: the turbine drives the generator at a constant speed ratio. The current turbine speed is obtained by measuring the generator speed. The generator sends its speed to the speed controller as an electrical feedback signal. The controller obtains the current turbine speed based on the feedback generator speed. Then, through the calculation of the PI control algorithm, the expected displacement of the fuel pump can be obtained through equations (15)-(16):

[0026]

[0027] In the formula, To set the turbine speed under the operating conditions, Let be the rotational speed error at time k. Let k be the theoretical fuel pump displacement. The proportional gain is the theoretical fuel pump displacement. The integral gain of the theoretical fuel pump displacement; The controller sends control commands to the servo system of the electronically controlled variable displacement fuel pump in the form of electrical signals. The servo system adjusts the pump angle of the fuel pump according to the control commands to change the propellant displacement pumped into the combustion chamber, thereby controlling the speed of the power system. The magnitude of the pump control voltage under the theoretical fuel pump displacement can be calculated by equations (17)-(18).

[0028] .

[0029] In formulas (17) and (18) of S3.2, This is the maximum theoretical displacement that the fuel pump can achieve. This refers to the swashplate angle of the fuel pump. This refers to the voltage value of the fuel pump electronic control signal. and These represent the maximum and minimum voltage values ​​that the fuel pump control electrical signal can achieve, respectively.

[0030] The specific process of S4: Dynamic system simulation software was used to perform full-condition dynamic simulation of the propulsion system of the cross-medium vehicle during water entry. The S4 model called the custom function in S3. Based on the simulation engine timing action and the simulation fuel pump angle response established in S3, the turbine speed, combustion chamber pressure and gas flow rate at one time step were obtained. The simulation conditions were updated and the next time step was calculated until the simulation time was met, so as to obtain the turbine speed distribution during water entry.

[0031] The beneficial effects of this invention are: The water entry control method for the propulsion system of a cross-medium vehicle provided by this invention can obtain the performance of the turbine and combustion chamber during the water entry of the cross-medium vehicle based on simulation results. It is applicable to underwater part-intake axial impulse turbine engines and axial flow propulsion pumps, and provides intuitive data support for system load changes, turbine speed changes, combustion chamber pressure changes and fuel pump displacement changes during the water entry process of the cross-medium vehicle. It can effectively solve the runaway and flameout phenomena that may be caused by the rapid coupling of multiple physical quantities during the water entry process. Attached Figure Description

[0032] Figure 1 This is a flowchart of the water entry process control method for the propulsion system of a cross-medium vehicle according to the present invention; Figure 2 This is a schematic diagram of the air-water propulsion system of the present invention. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, the water entry process control method for the propulsion system of a cross-medium vehicle provided by the present invention includes the following steps: S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system, respectively. S3. Construct an intelligent control module, calculate dynamic data in real time through the model established in S2, simulate the predetermined timing action of the engine by introducing a custom function, and realize the adaptive adjustment of the fuel pump angle based on the real-time calculated system speed feedback. S4. Establish a dynamic simulation model. By configuring the initial boundary conditions and the time step of the simulation calculation, perform dynamic simulation on the top-level system architecture model, each sub-model and control logic module described in S2 and S3, and finally generate the full-condition dynamic simulation model of the air-water propulsion system. The specific process of S1 is as follows: The air-water propulsion system consists of two propulsion units, one in the air and one underwater. The system shares a common combustion chamber, turbine, and underwater fuel, and is equipped with a transmission system with a clutch function.

[0035] Air navigation uses turbojet engines for propulsion, while underwater navigation uses pump-jet propulsion, employing a turbojet engine with adaptability to both air and water as the core power plant. This engine effectively supports the vehicle's efficient operation in both air and water media, and its corresponding air-water propulsion system structure is as follows: Figure 2 As shown. When using the air-powered propulsion system, OTTO-II fuel burns in the combustion chamber to produce a large amount of high-temperature, high-pressure gas. This gas drives the turbine to do work, then becomes exhaust gas and enters the mixing chamber. Air is drawn in and pressurized by the compressor through the intake duct. Subsequently, the air and exhaust gas undergo secondary combustion in the mixing chamber, and finally, the gas is ejected from the tail nozzle, propelling the vehicle forward. When using the underwater propulsion system, the turbine drives an axial-flow propulsion pump to rotate via a transmission mechanism. The axial-flow propulsion pump pressurizes and ejects water from the internal flow channel, propelling the vehicle forward.

[0036] The specific process of S2 is as follows: S2.1. Based on dynamic system simulation software, a combustion chamber model is established according to the actual working process of the combustion chamber, and the combustion chamber pressure is calculated by formulas (1)-(6):

[0037]

[0038]

[0039]

[0040]

[0041]

[0042] In the formula, The amount of gas produced per unit time. Let k be the turbine speed at time k. Let k be the fuel pump displacement at time k. The flow rate of the gas ejected from the nozzle. This represents the area of ​​the nozzle throat. For specific heat ratio, The gas constant is The combustion chamber temperature, Let K be the combustion chamber pressure at time k. This represents the change in gas mass flow rate. Let the mass of the gas at time k+1 be... Let K be the mass of the gas at time k. For simulating step size, This represents the change in combustion chamber pressure. The combustion chamber temperature, The free volume of the combustion chamber. The pressure in the combustion chamber at time k+1; S2.2. Based on dynamic system simulation software, the turbine output torque equation and the load model of the air-water propulsion system are established according to the dynamic torque equation. The turbine speed is calculated by formulas (7)-(12):

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] (13)

[0049] In the formula, To absorb torque for the lubricating oil pump, It is a positive constant. To absorb torque for the generator, It is a positive constant. To absorb torque for the fuel pump, It is a positive constant. Let k be the fuel pump displacement at time k. Let k be the combustion chamber pressure at time k. For the load torque of the axial flow propulsion pump, It is a positive constant. This is the load torque of the compressor. and It is a positive constant. For the resistance torque of the power system, To provide torque for the turbine output, The loss coefficient, The absolute velocity of the gas entering the turbine blades. The angle between the absolute velocity of the inlet and the plane of the wheel. The circumferential velocity of the turbine wheel. The velocity factor of the moving blade cascade, For the relative speed of imports, The relative velocity angle at the exit. Where is the radius of the turbine disk. Let k+1 be the turbine speed. The reduced moment of inertia of the underwater vehicle's propulsion system; The specific process of S3: The S3.1 engine timing sequence is designed as follows: From 0-2 seconds, the power system is an air-powered propulsion system, with the load consisting of the compressor and various auxiliary engines. The turbine speed is maintained at the air cruise design speed. At 2 seconds, the compressor is disconnected in the air, and the power system load consists of the loads of the auxiliary engines. The system idles for 2 seconds, with the turbine speed at the system idle speed. At 4 seconds, before the vehicle enters the water, the axial propulsion pump connects to the turbine, transforming the power system into an underwater propulsion system. The power system load consists of the axial propulsion pump and various auxiliary engines, with the turbine speed maintained at the underwater cruise design speed. When designing the engine timing, the high-speed clutch is generally connected to the compressor, while the low-speed clutch is usually connected to the axial propulsion pump. The solenoid valve clutch engagement time and its power load during operation must be considered in advance when disconnecting the compressor and connecting the axial propulsion pump.

[0050] The S3.2 fuel pump is controlled according to the actual variable displacement fuel pump. Its specific working process is as follows: the turbine drives the generator at a constant speed ratio, and the current turbine speed is obtained by measuring the generator speed. The generator sends its speed to the speed controller as an electrical feedback signal. The controller obtains the current turbine speed based on the feedback generator speed, and then calculates the expected displacement of the fuel pump through the PI control algorithm using equations (15)-(16):

[0051]

[0052] In the formula, To set the turbine speed under the operating conditions, Let be the rotational speed error at time k. Let k be the theoretical fuel pump displacement. The proportional gain is the theoretical fuel pump displacement. This is the integral gain of the theoretical fuel pump displacement.

[0053] The controller sends control commands as electrical signals to the servo system of the electronically controlled variable displacement fuel pump. The servo system adjusts the pump angle of the fuel pump according to the control commands to change the propellant displacement pumped into the combustion chamber, thereby controlling the speed of the power system. The pump control voltage under the theoretical fuel pump displacement can be calculated using equations (17)-(18):

[0054]

[0055] In the formula, This is the maximum theoretical displacement that the fuel pump can achieve. This refers to the swashplate angle of the fuel pump. This refers to the voltage value of the fuel pump electronic control signal. and These represent the maximum and minimum voltage values ​​that the fuel pump control electrical signal can achieve, respectively.

[0056] The initial conditions in S4 include the initial turbine disk speed, combustion chamber pressure and temperature, and fuel pump displacement.

[0057] The specific process of S4: Dynamic system simulation software was used to perform full-condition dynamic simulation of the propulsion system of a cross-medium vehicle during water entry. The S4 model called the custom function in S3. Based on the engine timing action and fuel pump angle response calculation in S3, the turbine speed, combustion chamber pressure and gas flow rate at one time step were obtained. The boundary conditions and parameters of the dynamic model were updated, and the next time step calculation was performed until the simulation time was met, so as to obtain the turbine speed distribution during water entry.

[0058] This invention establishes an air-to-water propulsion system model to create a model consistent with the actual propulsion system of a cross-medium vehicle. This model provides a realistic and effective solution to the impact of significant changes in parameters such as system load, turbine speed, and combustion chamber pressure during water entry, as well as the constant changes and coupling of various system parameters, on the propulsion system. It accurately simulates the control results of the propulsion system during the water entry process of a cross-medium vehicle. The purpose of using time-series simulation of the water entry process is to accurately calculate the changes in parameters of various parts of the system during water entry. The establishment of an electronically controlled variable displacement fuel pump system is to better simulate the effect of controlling fuel flow by adjusting the fuel pump displacement when the speed changes. The establishment of a dynamic model of the vehicle's propulsion system and a combustion chamber model is to better simulate the actual operation of the propulsion system during the water entry process of a cross-medium vehicle. The aforementioned model accurately calculates the changes in turbine speed, combustion chamber pressure, and fuel pump displacement, providing precise parameter settings for the dynamic simulation of the vehicle's propulsion system during water entry. Embedding user-defined functions into the dynamic model of the cross-medium vehicle's water entry process allows for better simulation of the control system's regulation of various turbine and combustion chamber parameters during water entry, accurately controlling turbine speed and combustion chamber pressure within a specific range to prevent flameout and runaway. This completes the dynamic simulation of the cross-medium vehicle's water entry process. The reliability of the control method during water entry can be assessed based on the turbine speed and combustion chamber pressure distribution at this point.

[0059] Through the above methods, the control method of the propulsion system of the present invention during the water entry process of a cross-medium vehicle can obtain the hydrodynamic performance of the propulsion system during the water entry process based on simulation results. It is applicable to the air-water propulsion system of various cross-medium vehicles, providing intuitive data support for the control method of the propulsion system during the water entry process. It can effectively solve the problem of drastic load changes during the water entry process. The operating parameters of each component inside the air-water propulsion system exhibit significant nonlinear and unsteady characteristics, reducing the occurrence of engine shutdown and runaway phenomena, and verifying the reliability of the propulsion system control method during the water entry process.

[0060] Example 1 The water entry process control method for the propulsion system of a cross-medium vehicle proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system respectively; S3. Construct a control logic module. The control logic module introduces custom functions to simulate the predetermined timing actions of the engine and realize the adaptive adjustment of the fuel pump angle based on the system speed feedback. S4. Establish a dynamic simulation model, configure the initial boundary conditions and time step of the simulation calculation, and perform dynamic simulation on the top-level system architecture model, each sub-model in S2 and the control logic module to generate a full-condition dynamic simulation model of the air-water propulsion system.

[0061] Example 2 The water entry process control method for the propulsion system of a cross-medium vehicle proposed in this embodiment includes the following steps: S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; The specific process of S1 is as follows: The air-water propulsion system is divided into two parts: an air propulsion system and an underwater propulsion system. The air propulsion system and the underwater propulsion system share a combustion chamber and a turbine, and both use underwater fuel. Its transmission system should also have a clutch function, which changes the power transmission path through an electromagnetic clutch, so that the connection between the main engine and the compressor can be disconnected during air deceleration and landing and underwater operation. During air navigation, the turbine drives the compressor for jet propulsion; during underwater navigation, the turbine drives the axial flow propulsion pump for water jet propulsion.

[0062] S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system respectively; S3. Construct a control logic module. The control logic module introduces custom functions to simulate the predetermined timing actions of the engine and realize the adaptive adjustment of the fuel pump angle based on the system speed feedback. S4. Establish a dynamic simulation model, configure the initial boundary conditions and time step of the simulation calculation, and perform dynamic simulation on the top-level system architecture model, each sub-model in S2 and the control logic module to generate a full-condition dynamic simulation model of the air-water propulsion system.

[0063] Example 3 The water entry process control method for the propulsion system of a cross-medium vehicle proposed in this embodiment includes the following steps: S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; The specific process of S1 is as follows: The air-water propulsion system is divided into two parts: an air propulsion system and an underwater propulsion system. The air propulsion system and the underwater propulsion system share a combustion chamber and a turbine, and both use underwater fuel. Its transmission system should also have a clutch function, which changes the power transmission path through an electromagnetic clutch, so that the connection between the main engine and the compressor can be disconnected during air deceleration and landing and underwater operation. During air navigation, the turbine drives the compressor for jet propulsion; during underwater navigation, the turbine drives the axial flow propulsion pump for water jet propulsion.

[0064] S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system respectively; S2 includes S2.1, and the specific process of S2.1 is as follows: Based on dynamic system simulation software, a combustion chamber model is established according to the actual working process of the combustion chamber, and the combustion chamber pressure is calculated by formulas (1)-(6):

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] In the formula, The amount of gas produced per unit time. Let k be the turbine speed at time k. Let k be the fuel pump displacement at time k. The flow rate of the gas ejected from the nozzle. This represents the area of ​​the nozzle throat. For specific heat ratio, The gas constant is The combustion chamber temperature, Let K be the combustion chamber pressure at time k. This represents the change in gas mass flow rate. Let the mass of the gas at time k+1 be... Let K be the mass of the gas at time k. For simulating step size, This represents the change in combustion chamber pressure. The combustion chamber temperature, The free volume of the combustion chamber. Let k be the combustion chamber pressure at time k+1.

[0071] S2 also includes S2.2, the specific process of which is as follows: Based on dynamic system simulation software, the turbine output torque equation and the load model of the air-water propulsion system are established according to the dynamic torque equation. The turbine speed is calculated by formulas (7)-(12):

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] (13)

[0078] In the formula, To absorb torque for the lubricating oil pump, It is a positive constant. To absorb torque for the generator, It is a positive constant. To absorb torque for the fuel pump, It is a positive constant. Let k be the fuel pump displacement at time k. Let k be the combustion chamber pressure at time k. For the load torque of the axial flow propulsion pump, It is a positive constant. This is the load torque of the compressor. and It is a positive constant. For the resistance torque of the power system, To provide torque for the turbine output, The loss coefficient, The absolute velocity of the gas entering the turbine blades. The angle between the absolute velocity of the inlet and the plane of the wheel. The circumferential velocity of the turbine wheel. The velocity factor of the moving blade cascade, For the relative speed of imports, The relative velocity angle at the exit. Where is the radius of the turbine disk. Let k+1 be the turbine speed. This is the reduced moment of inertia of the underwater vehicle's propulsion system.

[0079] S3. Construct a control logic module. The control logic module introduces custom functions to simulate the predetermined timing actions of the engine and realize the adaptive adjustment of the fuel pump angle based on the system speed feedback. S4. Establish a dynamic simulation model, configure the initial boundary conditions and time step of the simulation calculation, and perform dynamic simulation on the top-level system architecture model, each sub-model in S2 and the control logic module to generate a full-condition dynamic simulation model of the air-water propulsion system.

[0080] Example 4 The water entry process control method for the propulsion system of a cross-medium vehicle proposed in this embodiment, based on embodiment 3, includes S3.1 in step S3, the specific process of which is as follows: The engine timing sequence is designed as follows: First, from 0-2 seconds, the power system is an air-powered propulsion system, with the load consisting of the compressor and various auxiliary engines. The turbine speed is maintained at the air cruise design speed. At 2 seconds, the compressor is disconnected in the air, and the power system load consists of the loads of the various auxiliary engines. The system idles for 2 seconds, and the turbine speed is the system idle speed. At 4 seconds, before the vehicle enters the water, the axial propulsion pump is connected to the turbine, and the power system becomes an underwater propulsion system. The power system load consists of the axial propulsion pump and various auxiliary engines, and the turbine speed is maintained at the underwater cruise design speed. When designing the engine timing, the high-speed clutch is generally connected to the compressor, and the low-speed clutch is usually connected to the axial propulsion pump. When disconnecting the compressor and connecting the axial propulsion pump, the solenoid valve clutch engagement time needs to be considered in advance, as does its power load during solenoid valve clutch operation.

[0081] Example 5 The water entry process control method for the propulsion system of a cross-medium vehicle proposed in this embodiment, based on embodiment 4, includes S3.2 in step S3, and its specific process is as follows: The fuel pump is controlled according to the actual variable displacement fuel pump. The specific working process is as follows: the turbine drives the generator at a constant speed ratio. The current turbine speed is obtained by measuring the generator speed. The generator sends its speed to the speed controller as an electrical feedback signal. The controller obtains the current turbine speed based on the feedback generator speed. Then, through the calculation of the PI control algorithm, the expected displacement of the fuel pump can be obtained through equations (15)-(16):

[0082]

[0083] In the formula, To set the turbine speed under the operating conditions, Let be the rotational speed error at time k. Let k be the theoretical fuel pump displacement. The proportional gain is the theoretical fuel pump displacement. The integral gain of the theoretical fuel pump displacement; The controller sends control commands to the servo system of the electronically controlled variable displacement fuel pump in the form of electrical signals. The servo system adjusts the pump angle of the fuel pump according to the control commands to change the propellant displacement pumped into the combustion chamber, thereby controlling the speed of the power system. The magnitude of the pump control voltage under the theoretical fuel pump displacement can be calculated by equations (17)-(18).

[0084] .

[0085] In formulas (17) and (18) of S3.2, This is the maximum theoretical displacement that the fuel pump can achieve. This refers to the swashplate angle of the fuel pump. This refers to the voltage value of the fuel pump electronic control signal. and These represent the maximum and minimum voltage values ​​that the fuel pump control electrical signal can achieve, respectively.

[0086] Example 6 The water entry control method for the propulsion system of a cross-medium vehicle proposed in this embodiment, based on embodiment 5, specifically involves the following steps in S4: Dynamic system simulation software is used to perform a full-condition dynamic simulation of the propulsion system during the water entry process of the cross-medium vehicle. The S4 model calls a custom function from S3, and based on the simulation engine timing and fuel pump angle response established in S3, the turbine speed, combustion chamber pressure, and gas flow rate at one time step are obtained. The simulation conditions are then updated, and the next time step is calculated until the simulation time is met, thus obtaining the turbine speed distribution during the water entry process.

Claims

1. A method for controlling the water entry process of a cross-medium vehicle's propulsion system, characterized in that, Including the following: S1. Establish a top-level system architecture model for the air-water propulsion system of a cross-medium vehicle; S2. Based on the top-level system architecture model, establish the combustion chamber model, the turbine output torque equation, and the load model of the air-water propulsion system respectively; S3. Construct a control logic module. The control logic module introduces custom functions to simulate the predetermined timing actions of the engine and realize the adaptive adjustment of the fuel pump angle based on the system speed feedback. S4. Establish a dynamic simulation model, configure the initial boundary conditions and time step of the simulation calculation, and perform dynamic simulation on the top-level system architecture model, each sub-model in S2 and the control logic module to generate a full-condition dynamic simulation model of the air-water propulsion system.

2. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 1, characterized in that, The specific process of S1 is as follows: The air-water propulsion system is divided into two parts: an air propulsion system and an underwater propulsion system. The air propulsion system and the underwater propulsion system share a combustion chamber and a turbine, and both use underwater fuel. Its transmission system should also have a clutch function, which changes the power transmission path through an electromagnetic clutch, so that the connection between the main engine and the compressor can be disconnected during air deceleration and landing and underwater operation. During air navigation, the turbine drives the compressor for jet propulsion; during underwater navigation, the turbine drives the axial flow propulsion pump for water jet propulsion.

3. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 1, characterized in that, S2 includes S2.1, and the specific process of S2.1 is as follows: Based on dynamic system simulation software, a combustion chamber model is established according to the actual working process of the combustion chamber, and the combustion chamber pressure is calculated by formulas (1)-(6): In the formula, The amount of gas produced per unit time. Let k be the turbine speed at time k. Let k be the fuel pump displacement at time k. The flow rate of the gas ejected from the nozzle. This represents the area of ​​the nozzle throat. For specific heat ratio, The gas constant is The combustion chamber temperature, Let K be the combustion chamber pressure at time k. This represents the change in gas mass flow rate. Let the mass of the gas at time k+1 be... Let K be the mass of the gas at time k. For simulating step size, This represents the change in combustion chamber pressure. The combustion chamber temperature, The free volume of the combustion chamber. Let k be the combustion chamber pressure at time k+1.

4. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 1, characterized in that, S2 also includes S2.2, the specific process of which is as follows: Based on dynamic system simulation software, the turbine output torque equation and the load model of the air-water propulsion system are established according to the dynamic torque equation. The turbine speed is calculated by formulas (7)-(12): (13) In the formula, To absorb torque for the lubricating oil pump, It is a positive constant. To absorb torque for the generator, It is a positive constant. To absorb torque for the fuel pump, It is a positive constant. Let k be the fuel pump displacement at time k. Let k be the combustion chamber pressure at time k. For the load torque of the axial flow propulsion pump, It is a positive constant. This is the load torque of the compressor. and It is a positive constant. For the resistance torque of the power system, To provide torque for the turbine output, The loss coefficient, The absolute velocity of the gas entering the turbine blades. The angle between the absolute velocity of the inlet and the plane of the wheel. The circumferential velocity of the turbine wheel. The velocity factor of the moving blade cascade, For the relative speed of imports, The relative velocity angle at the exit. Where is the radius of the turbine disk. Let k+1 be the turbine speed. This is the reduced moment of inertia of the underwater vehicle's propulsion system.

5. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 1, characterized in that, S3 includes S3.1, and its specific process is as follows: The engine timing sequence is designed as follows: First, from 0-2 seconds, the power system is an air-powered propulsion system, with the load consisting of the compressor and various auxiliary engines. The turbine speed is maintained at the air cruise design speed. At 2 seconds, the compressor is disconnected in the air, and the power system load consists of the loads of the various auxiliary engines. The system idles for 2 seconds, and the turbine speed is the system idle speed. At 4 seconds, before the vehicle enters the water, the axial propulsion pump is connected to the turbine, and the power system becomes an underwater propulsion system. The power system load consists of the axial propulsion pump and various auxiliary engines, and the turbine speed is maintained at the underwater cruise design speed. When designing the engine timing, the high-speed clutch is generally connected to the compressor, and the low-speed clutch is usually connected to the axial propulsion pump. When disconnecting the compressor and connecting the axial propulsion pump, the solenoid valve clutch engagement time needs to be considered in advance, as does its power load during solenoid valve clutch operation.

6. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 5, characterized in that, S3 includes S3.2, and its specific process is as follows: The fuel pump is controlled according to the actual variable displacement fuel pump. The specific working process is as follows: the turbine drives the generator at a constant speed ratio. The current turbine speed is obtained by measuring the generator speed. The generator sends its speed to the speed controller as an electrical feedback signal. The controller obtains the current turbine speed based on the feedback generator speed. Then, through the calculation of the PI control algorithm, the expected displacement of the fuel pump can be obtained through equations (15)-(16): In the formula, To set the turbine speed under the operating conditions, Let be the rotational speed error at time k. Let k be the theoretical fuel pump displacement. The proportional gain is the theoretical fuel pump displacement. The integral gain of the theoretical fuel pump displacement; The controller sends control commands to the servo system of the electronically controlled variable displacement fuel pump in the form of electrical signals. The servo system adjusts the pump angle of the fuel pump according to the control commands to change the propellant displacement pumped into the combustion chamber, thereby controlling the speed of the power system. The magnitude of the pump control voltage under the theoretical fuel pump displacement can be calculated by equations (17)-(18). 。 7. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 6, characterized in that, In formulas (17) and (18) of S3.2, This is the maximum theoretical displacement that the fuel pump can achieve. This refers to the swashplate angle of the fuel pump. This refers to the voltage value of the fuel pump electronic control signal. and These represent the maximum and minimum voltage values ​​that the fuel pump control electrical signal can achieve, respectively.

8. The water entry process control method for the propulsion system of a cross-medium vehicle according to claim 7, characterized in that, The specific process of S4 is as follows: Dynamic system simulation software was used to perform full-condition dynamic simulation of the propulsion system of the cross-medium vehicle during water entry. The S4 model called the custom function in S3. Based on the simulation engine timing action and the simulation fuel pump angle response established in S3, the turbine speed, combustion chamber pressure and gas flow rate at one time step were obtained. The simulation conditions were updated and the next time step was calculated until the simulation time was met, so as to obtain the turbine speed distribution during water entry.

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