An experimental method for a gas generator for adjusting the water-entry attitude of a vehicle

Abstract

An experimental method of a gas production device for adjusting the water-entry posture of a vehicle relates to the technical field of water-entry vehicle model experiment. In order to solve the technical defects of the existing experimental method for adjusting the posture under complex water-entry conditions, the technical scheme provided by the present application includes: calculating and obtaining the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity; combining the geometric arrangement model of the propellant, deriving the law of the propellant gas production area changing with time, and establishing a gas production speed model; predicting the gas cavity exhaust characteristics; collecting the high-pressure gas cavity pressure and exhaust flow data during the actual exhaust process through experiments, comparing and analyzing the experimental data with the prediction results, and correcting the parameters of the propellant arrangement model and the pressure prediction model according to the differences. It is suitable for experimental research on the posture adjustment and cavitation suppression of the vehicle during high-speed water entry.

Description

Technical Field

[0001] This invention relates to the field of experimental technology for waterborne vehicle models, specifically to an experimental method for a gas-generating device used to adjust the waterborne attitude of a vehicle. Background Technology

[0002] With the development of high-speed vehicle technology, attitude stability during the water exit process has become a key issue in research and engineering practice. When a vehicle moves at high speed in water, a large area of ​​natural cavitation forms on its surface. The generation, development, and collapse of cavitation bubbles lead to violent fluctuations in the flow field, subjecting the vehicle to complex nonlinear hydrodynamic loads, significantly affecting its attitude control accuracy and motion stability, and may even lead to instability. To address this issue, researchers have proposed a surface aeration technique to suppress cavitation. By releasing gas onto the outer surface of the vehicle, the local flow field is adjusted, thereby mitigating the cavitation effect and achieving attitude adjustment.

[0003] Currently, ventilation and attitude control technology mainly relies on a gas source device to stably output high-temperature, high-pressure gas and precisely control the exhaust process. Research focuses on gas source control methods, device structural compactness, and internal space compatibility. A typical research result is exemplified by patent CN109596313B, which proposes an active ventilation experimental device based on a gas chamber. This device inflates the internal gas storage chamber of the vessel body through an external air pressure system and uses a control system to release gas as needed for attitude control. However, this technology involves a large gas chamber structure that occupies a significant amount of internal space, limiting the arrangement of other measurement and control units. Furthermore, the gas storage chamber structure is limited by strength and sealing performance, making it impossible to meet the requirements of high-frequency, high-pressure, and rapid exhaust.

[0004] Another type of device is embodied in patent publication number CN203732238U, which integrates the air storage tank with the ship's structure. By setting up a "frustum-shaped compartment," the overall strength and air storage capacity are improved, while reducing the encroachment on the internal space. This design has made progress in structural optimization, but it still relies on an external air source for inflation, resulting in complex pre-experiment preparation, cumbersome operation procedures, and limited air source control precision, making it difficult to meet the engineering requirements of real-time dynamic adjustment of high-speed water exit attitude.

[0005] In summary, the following problems generally exist in existing technologies:

[0006] The gas storage device is large in size and significantly occupies the limited internal space of the vessel.

[0007] The structural strength and sealing performance of the gas storage tank are difficult to balance, making it unable to meet the requirements of high-temperature and high-pressure gas production.

[0008] The system relies on an external gas source, making operation cumbersome and with a low degree of automation.

[0009] The lack of a dynamic control mechanism for the high-pressure gas production rate and exhaust process results in limited attitude adjustment effect.

[0010] Therefore, there is an urgent need to propose an experimental method that is compact, highly integrated, has adjustable gas emission parameters, and is suitable for attitude adjustment requirements under complex water discharge conditions, in order to solve the problems of inaccurate high-pressure gas source control, complex coupling relationship between gas generation and exhaust capabilities, and difficulty in integrating experimental devices in the existing technology. Summary of the Invention

[0011] To address the shortcomings of existing experimental methods for attitude adjustment under complex water discharge conditions, such as inaccurate high-pressure gas source control, complex coupling relationships between gas generation and exhaust capabilities, and difficulty in integrating experimental devices, the present invention provides the following technical solution:

[0012] An experimental method for a gas-generating device used for adjusting the attitude of a vehicle emerging from the water includes:

[0013] The steps involve deriving theoretical thermohydrodynamics and the jet flow equation, calculating and obtaining the functional relationship between the jet cross-sectional area and the internal pressure of the high-pressure gas chamber;

[0014] Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber, and combined with the propellant geometric arrangement model, the steps for deriving the law of change of the propellant gas production area with time and establishing the gas production rate model are as follows.

[0015] The steps for predicting the exhaust characteristics of the gas chamber are to calculate the process of pressure change over time in the high-pressure gas chamber and the exhaust parameters of the nozzle by using the gas production velocity model and gas production evolution law.

[0016] The steps involve collecting high-pressure chamber pressure and exhaust flow data during the actual exhaust process, comparing and analyzing the experimental data with the predicted results, and correcting the parameters of the propellant arrangement model and pressure prediction model based on the feedback of the differences.

[0017] Furthermore, a preferred embodiment is provided in which the functional relationship between the cross-sectional area of ​​the nozzle and the internal pressure of the high-pressure air chamber is established based on the principle of gas continuity and the assumption of one-dimensional isentropic flow, wherein the airflow velocity at the nozzle is equal to the speed of sound.

[0018] Furthermore, a preferred embodiment is provided in which the change of the propellant gas production area over time is based on the gas production initiation surface determined by the propellant arrangement and the propagation path, and a linear fitting model is used to initially estimate the propellant gas production and deployment process.

[0019] Furthermore, a preferred embodiment is provided in which the gas production rate model is preset with constant parameters based on the propellant type, and the gas production mass per unit time is initially estimated in combination with the gas production expansion area.

[0020] Furthermore, a preferred embodiment is provided in which the pressure change in the high-pressure gas chamber is estimated using an ideal gas state model, and a dynamic balance solution is obtained by combining the cumulative mass of the high-temperature and high-pressure gas with the discharge flow rate.

[0021] Furthermore, a preferred embodiment is provided, wherein the experimental data includes the pressure curve of the high-pressure chamber acquired by the pressure sensor and the sequence of images of the evolution of exhaust bubbles captured by the high-speed camera system.

[0022] An experimental system for a gas-generating device for adjusting the attitude of a vehicle emerging from the water is also provided, comprising:

[0023] A module that calculates and obtains the functional relationship between the cross-sectional area of ​​the nozzle and the internal pressure of the high-pressure air chamber by deriving theoretical thermohydrodynamics and the flow equation of the nozzle;

[0024] Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber, and combined with the propellant geometric arrangement model, the law of change of the propellant gas production area with time is derived, and a module for establishing the gas production rate model is established.

[0025] This module calculates the pressure change over time within the high-pressure gas chamber and the nozzle exhaust parameters by using a gas production velocity model and gas production evolution law, and predicts the exhaust characteristics of the gas chamber.

[0026] This module collects high-pressure chamber pressure and exhaust flow data during the actual exhaust process, compares and analyzes the experimental data with the predicted results, and corrects the parameters of the propellant arrangement model and pressure prediction model based on the feedback of the differences.

[0027] A computer storage medium is also provided for storing a computer program, which, when read by the computer, executes the method.

[0028] A computer is also provided, including a processor and a storage medium, wherein the computer executes the method when the processor reads a computer program stored in the storage medium.

[0029] A computer program product is also provided, which, when executed, implements the method described.

[0030] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows:

[0031] By theoretically modeling and calculating the coupling relationship between propellant arrangement and nozzle parameters, predictable control of the output flow rate and pressure of high-temperature and high-pressure gas can be achieved. Compared with existing technologies that rely on experience to adjust or fix the gas source structure, this method can predict the gas discharge capacity before the experiment, thereby improving the accuracy of gas production control and the scientific nature of attitude adjustment scheme design.

[0032] The interchangeable nozzle structure and modular propellant arrangement design make adjusting the gas production and exhaust flow rate highly efficient and flexible. Traditional devices such as CN109596313B have strong enclosed structures and are difficult to modify, making it difficult to quickly adapt to different experimental requirements. In contrast, this solution supports the rapid change of gas output characteristics by replacing nozzles with different diameters or adjusting the propellant distribution pattern (such as annular and crescent shapes), adapting to complex and changing operating conditions.

[0033] The gas generation device is encapsulated within a compact, high-strength tank, employing an O-ring groove sealing structure and a PTFE gasket, effectively improving the sealing and pressure resistance of the gas generation chamber. Compared to the "frustum-shaped cabin" design proposed in CN203732238U, this invention significantly reduces space occupation, improves the utilization rate of the internal space of the vessel, and provides structural margin for installing other testing systems or control units.

[0034] By integrating a pressure sensor into the gas generation device and calibrating it using theoretical models and real-time pressure measurements, pressure and flow curves close to actual operating conditions can be obtained after the experiment, thereby enabling reverse optimization of design parameters. This data feedback mechanism complements existing passive testing methods, improving the closed-loop control capability and repeatability of the experimental system.

[0035] By deploying a high-speed camera system on the front and left side of the vehicle, multi-angle synchronous acquisition of the attitude change process is achieved, providing image evidence for experimental result analysis and attitude adjustment effect evaluation. Compared with existing methods that rely on a limited number of sensor points to acquire data, this solution enables full-process visualization analysis, facilitating the identification of cavitation effects and attitude instability sources, thereby promoting the upgrading of attitude adjustment strategies from qualitative judgment to quantitative optimization.

[0036] It supports iterative adjustments to propellant placement and nozzle parameters based on experimental results, allowing for precise control of gas generation rhythm and exhaust pulses by adjusting the throat diameter or propellant quantity and distribution. This multi-variable joint adjustment mechanism can be extended to meet the attitude control requirements of vehicles under various speed, depth, and load conditions, significantly improving the adaptability and engineering practical value of the experimental setup.

[0037] It is applicable to experimental studies related to attitude adjustment and cavitation suppression during high-speed water exit of a vehicle. Attached Figure Description

[0038] Figure 1 a is a schematic diagram of the propellant ring arrangement;

[0039] Figure 1 b is a schematic diagram of the crescent-shaped arrangement of the propellant;

[0040] Figure 1c is a graph showing the trend of outlet flow rate for propellant ring arrangement;

[0041] Figure 1 d represents the trend of outlet flow rate variation for the crescent-shaped propellant arrangement.

[0042] Figure 2 a is a graph showing the pressure variation trend in the high-pressure chamber with the propellant arranged in a ring;

[0043] Figure 2 b is a graph showing the pressure change trend in the high-pressure chamber with the propellant arranged in a crescent shape.

[0044] Figure 3 This is a front view of a schematic diagram of a gas-generating device;

[0045] Figure 4 A schematic diagram of the aircraft carrier;

[0046] Figure 5 A schematic diagram of the underwater vehicle emergence test system;

[0047] Figure 6 This is a front view of a schematic diagram of a high-speed camera system.

[0048] Figure 7 This is a top view of a schematic diagram of a high-speed camera system.

[0049] Figure 8 This is a workflow diagram.

[0050] The components include: end cap 1; tank body 2; screw plug 3; plug 4; pressure ring 5; small nut 6; mounting plate 7; propellant 8; retaining ring 9; nozzle 10; O-ring 11; O-ring groove 12; high-strength bolt assembly 13; sensor base 14; gas generation device 15; gas collection chamber 16; exhaust port 17; vehicle body 18; power unit 19; cylinder 20; membrane 21; sealing ring 22; base 23; and high-speed camera 24. Detailed Implementation

[0051] To make the advantages and benefits of the technical solution provided by the present invention clearer, the technical solution provided by the present invention will now be described in further detail with reference to the accompanying drawings, specifically:

[0052] Implementation Method 1: This implementation method provides an experimental method for a gas-generating device used for adjusting the attitude of a vehicle emerging from the water, including:

[0053] The steps involve deriving theoretical thermohydrodynamics and the jet flow equation, calculating and obtaining the functional relationship between the jet cross-sectional area and the internal pressure of the high-pressure gas chamber;

[0054] Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber, and combined with the propellant geometric arrangement model, the steps for deriving the law of change of the propellant gas production area with time and establishing the gas production rate model are as follows.

[0055] The steps for predicting the exhaust characteristics of the gas chamber are to calculate the process of pressure change over time in the high-pressure gas chamber and the exhaust parameters of the nozzle by using the gas production velocity model and gas production evolution law.

[0056] The steps involve collecting high-pressure chamber pressure and exhaust flow data during the actual exhaust process, comparing and analyzing the experimental data with the predicted results, and correcting the parameters of the propellant arrangement model and pressure prediction model based on the feedback of the differences.

[0057] The functional relationship between the cross-sectional area of ​​the nozzle and the internal pressure of the high-pressure air chamber is established based on the principle of gas continuity and the assumption of one-dimensional isentropic flow, wherein the airflow velocity at the nozzle is equal to the speed of sound.

[0058] The change in the propellant gas production area over time is based on the gas production initiation surface determined by the propellant arrangement and the propagation path. A linear fitting model is used to initially estimate the propellant gas production and deployment process.

[0059] The gas production rate model is based on preset constant parameters according to the propellant type, and uses the gas production area to make a preliminary estimate of the gas production mass per unit time.

[0060] The pressure change in the high-pressure gas chamber is estimated using an ideal gas state model, and a dynamic balance solution is obtained by combining the cumulative mass of high-temperature and high-pressure gas with the discharge flow rate.

[0061] The experimental data includes pressure curves of the high-pressure chamber collected by pressure sensors and a sequence of images of the evolution of exhaust bubbles captured by a high-speed camera system.

[0062] Implementation Method Two: This implementation method is a further detailed description of Implementation Method One, specifically:

[0063] In the device section:

[0064] Figure 1 Figure 'a' shows a schematic diagram of a propellant ring arrangement, where 7 represents the mounting plate and 8 represents the propellant. It can be seen that in this ring arrangement, multiple propellants 8 are evenly distributed on the mounting plate 7 in a ring shape, forming an approximately circular charge layout around the center of the mounting plate. Each propellant 8 is placed symmetrically along the circumference, resulting in a balanced overall structure to ensure uniform generation and distribution of high-pressure gas within the high-pressure chamber after gas production. The mounting plate 7 serves to support and position the propellant, and it typically has fixing holes or bosses to secure the propellant in place using fasteners such as small nuts, thus preventing displacement of the propellant before gas production.

[0065] Figure 1 Figure b shows a schematic diagram of the crescent-shaped propellant arrangement. In this arrangement, the propellant 8 is locally concentrated on the mounting plate 7, mainly located on one side of the plate, with an overall shape resembling a portion of a ring (crescent-shaped). This arrangement results in the propellant 8 not being completely symmetrically distributed in space, but rather forming a state where one side of the mounting plate 7 is densely packed while the other side is relatively empty. The crescent-shaped arrangement results in a different propellant concentration in the high-pressure chamber compared to the annular arrangement. Its function is to prolong the duration of gas generation, achieving a longer gas output period (correspondingly, the peak pressure is slightly lower, but the duration is longer). Both arrangements affect the pressure and flow output characteristics of the gas generation device by altering the spatial distribution of the propellant 8 within the high-pressure chamber, each with its own advantages. A suitable propellant layout can be selected based on experimental requirements.

[0066] like Figure 3The diagram shows a longitudinal cross-sectional view of the gas generating device 15. In the diagram, 1 is the end cap, 2 is the tank body, 14 is the sensor base, 10 is the nozzle, 3 is the screw plug, 4 is the plug, 5 is the pressure ring, 6 is the small nut, 7 is the mounting plate, 8 is the propellant, 9 is the retaining ring, 11 is the O-ring, 12 is the O-ring groove, and 13 is the high-strength bolt assembly. The end cap 1 is securely connected to the tank body 2 via multiple sets of high-strength bolt assemblies 13, sealing the top of the tank body into a high-pressure gas generating chamber (an O-ring 11 is provided at the joint between the end cap and the tank body, embedded in the O-ring groove 12 to ensure airtightness). The end cap 1 has an opening for installing the gas generating device or filling the propellant. A plug 4 is installed at the reserved inlet on its left side, and the plug 4 is fixed and locked by the screw plug 3, thereby sealing the inlet of the end cap 1. After the screw plug 3 is tightened, its pores are coated with silicone rubber to further ensure a seal. A sensor base 14 is located on the upper right side of the end cap 1 for mounting measuring elements such as pressure sensors. When installing the sensor, an annular silicone pad is placed at the bottom of the base 14 to ensure a reliable seal at the connection between the sensor and the high-pressure chamber. Inside the tank 2 of the gas generating device 15, several propellant blocks 8 are installed, which are assembled and fixed into a propellant assembly using mounting plates 7 and small nuts 6. Specifically, the mounting plate 7 has through holes or pillars for the propellant to pass through. After the propellant 8 is fitted onto it, it is locked by tightening the small nuts 6, thereby firmly stacking multiple propellant blocks into one unit. When the propellant assembly is placed inside the tank 2, it is positioned and limited by a retaining ring 9, and a pressure ring 5 above it applies a pre-tightening force to press and fix the propellant assembly from the top, keeping it stable inside the tank. The lower end of the tank 2 is connected to a nozzle 10, which forms a constricted throat inside to control the ejection flow rate of the high-temperature generated gas. An annular O-ring groove 12 is opened around the nozzle 10, and an O-ring 11 is built in to ensure a seal at the connection between the nozzle and the downstream assembly. In addition, a thin polytetrafluoroethylene gasket (high-temperature resistant sealing gasket) is placed at the connection between tank 2 and the gas collection chamber inside the subsequent vessel to prevent high-temperature gas leakage and to provide thermal insulation and buffering. After the above components are assembled as shown in the figure, a complete high-pressure gas generation chamber structure of the gas generation device 15 is formed. Its function is to contain the high-temperature and high-pressure gas generated by the propellant 8 after gas generation, and to directionally eject the gas through the lower nozzle 10.

[0067] like Figure 4As shown, the gas generating device 15 is installed below the gas collection chamber 16 inside the vessel 18. In the figure, 15 is the gas generating device, 16 is the gas collection chamber, 17 is the exhaust port, and 18 is the vessel. The gas generating device 15 is generally located in the upper-middle part of the vessel 18, adjacent to the gas collection chamber. A flange interface for installing the gas generating device 15 is pre-machined on the corresponding section of the vessel 18 (this flange is an integral structure with the gas collection chamber 16 inside the vessel). The gas generating device 15 is fixed to this flange using a high-strength bolt assembly, thereby precisely aligning the outlet of the nozzle 10 of the gas generating device with the inlet flange of the gas collection chamber 16. During installation, a gasket (such as a polytetrafluoroethylene gasket) is placed between the nozzle 10 and the flange interface. This gasket, together with the O-rings 11 around the nozzle, ensures the sealing and insulation of the connection between the gas generating device 15 and the gas collection chamber 16. After the gas generating device 15 starts generating gas, the high-temperature, high-pressure gas is ejected through the nozzle 10 and directly enters the gas collection chamber above the vessel 18. The gas collection chamber 16 acts as a buffer cavity, communicating with the outside through several exhaust ports 17 on the hull of the vessel. These exhaust ports 17 are evenly distributed around the circumference of the vessel 18 (i.e., around its shoulder area). Therefore, after high-pressure gas enters the gas collection chamber 16 through the gas generation device 15, it is evenly discharged outside the vessel 18 through the multiple exhaust ports 17 around its outer shell, achieving ventilation of the vessel surface. After the gas generation device 15 is installed, the vessel section containing the device is reconnected and reassembled with the rest of the vessel 18 to restore the complete vessel structure. Through the above installation, the gas generation device 15, the gas collection chamber 16, and the exhaust ports 17 together form a continuous gas generation channel, through which high-temperature gas is guided from the inside of the vessel to the outside, providing the airflow required for attitude control.

[0068] like Figure 5The diagram shows the structure of the water-emerging experimental system for the vehicle. In the diagram, 18 is the vehicle, 20 is a cylinder, 21 is a membrane, 22 is a sealing ring, 23 is a base, and 19 is a power unit. The cylinder 20 is vertically mounted on the base 23, forming a cylindrical experimental cavity that accommodates the vehicle 18 and the water medium. The vehicle 18 is inserted into the cylinder 20 from above by hoisting, and its outer diameter is sealed to the inner diameter of the cylinder 20 via the sealing ring 22. The sealing ring 22 is fixedly installed on the outer surface of the vehicle 18 and tightened with bolts, forming a water-tight sliding interface between the vehicle and the inner wall of the cylinder. Once the vehicle is placed inside the cylinder and the sealing ring is in place, a membrane 21 is adhered to the top opening of the cylinder 20. This membrane 21 is a fragile, sheet-like material that acts as a diaphragm simulating the water surface or the upper boundary of the closed cavity; it can be ruptured during the upward movement of the vehicle 18. After the membrane is applied to the top of the cylinder, the power unit 19 is installed and connected to the cylinder 20 and secured with a high-strength bolt assembly. The power unit 19, for example, can be a catapult mechanism, a compressed air drive, or other thrust-providing mechanism, installed below the cylinder 20 (or connected to the base 23) to apply an upward thrust to the bottom of the launch vehicle 18. In the entire experimental system, the base 23 provides support, the cylinder 20 simulates a water tank or launch tube in which the launch vehicle 18 is placed, preparing for its ascent, the membrane 21 simulates the initial sealing conditions of the water surface, and the power unit 19 provides the initial velocity and energy required for the launch vehicle to emerge from the water. All components are connected by bolts and sealing elements to ensure system rigidity and airtightness. Once assembled, preparations can begin for the launch vehicle's water emergence test.

[0069] like Figure 6 and Figure 7 As shown, the water-emerging experiment also includes a high-speed camera system for recording the vehicle's motion and gas generation effects. Figure 6 This is a frontal view diagram of the high-speed camera system, where 18 represents the vehicle and 24 represents the high-speed camera. A support frame for the high-speed camera 24 is mounted directly in front of the vehicle 18, facing it. Multiple high-speed cameras are installed on this frame at different heights. These cameras are arranged vertically in layers, with their lenses pointing at different heights the vehicle 18 may pass through, capturing images of the vehicle's attitude changes during its ascent. The multiple high-speed cameras working together in front can record the movement of the vehicle's frontal surface and the changes in the effectiveness of cavitation suppression during the entire process of the vehicle 18 emerging from the water and rising.

[0070] Figure 7This is a top-down view of the high-speed camera system. The circular unit 18 represents the position of the vehicle's cross-section, and 24 is the high-speed camera. It can be seen that a high-speed camera 24 is also positioned directly to the left (side view) of the vehicle's path, used to capture its movement from the side. The cameras on the left are mounted on another support frame, with multiple units arranged at different heights to record the vehicle's emergence from the water and its underwater movement from a side view. Figure 6 and Figure 7 The high-speed camera arrays on the front and sides of the device simultaneously acquire frontal and side images of the movement of the vehicle 18, allowing for a comprehensive observation of the effect of the gas generating device 15 on the attitude adjustment of the vehicle, providing multi-angle data support and analytical basis for the experiment.

[0071] Theoretical calculation stage

[0072] First, the required exhaust flow rate for attitude adjustment of the aircraft was determined through theoretical calculations, which then led to the selection of key parameters such as the propellant arrangement and nozzle diameter. The calculations were based on the gas continuity equation and one-dimensional isentropic flow theory, deriving that the main parameters affecting the outlet flow rate of the high-pressure chamber (high-pressure chamber of the gas-generating device) are the chamber pressure and the nozzle cross-sectional area. Simultaneously, the influence of propellant arrangement on the chamber pressure was analyzed, clarifying that the propellant gas generation rate, cross-sectional gas generation area, and gas generation rate are the key factors determining the high-pressure chamber pressure. These theoretical calculation results provided a basis for the structural design and parameter selection of the experimental setup.

[0073] Detailed description:

[0074] Based on the operational requirements for adjusting the vehicle's attitude upon exiting the water, the total outlet flow rate of the required exhaust ports is estimated. According to the law of conservation of mass, the total exhaust volume of all exhaust ports is equal to the inlet flow rate of the gas collection chamber 16, which is also equal to the outlet gas production flow rate of the gas generating device 15. Therefore, the outlet flow rate of the gas generating device is first calculated, and then this flow rate is divided by the number of exhaust ports to obtain the unit flow rate required by each exhaust port. Based on the calculation results, the propellant type and its arrangement that meet the requirements, as well as the corresponding matching nozzle throat diameter, are preliminarily selected.

[0075] This paper analyzes the process of gas discharge from the high-pressure chamber of a gas-generating device via the nozzle using the gas continuity equation and one-dimensional isentropic flow theory. At the narrowest point of the nozzle (the nozzle), the airflow reaches a critical state (the flow velocity reaches the speed of sound). The flow rate of high-temperature gas passing through the nozzle per unit time mainly depends on the gas pressure inside the high-pressure chamber and the cross-sectional area of ​​the nozzle. Since the gas generation characteristic parameters are fixed after the propellant type is determined (e.g., gas constant, heat of generation, etc.), under ideal conditions where friction and heat losses are ignored, the instantaneous outlet flow rate of the high-pressure chamber is mainly determined by the high-pressure chamber pressure and the nozzle cross-sectional area. A larger throat diameter results in a larger nozzle cross-sectional area and a higher gas flow rate discharged from the high-pressure chamber per unit time; conversely, a smaller throat diameter results in a lower outlet flow rate.

[0076] After determining the nozzle size, further analysis of the factors influencing the high-pressure chamber pressure is needed. The change in high-pressure chamber pressure over time depends on the dynamic balance between the generation and discharge rates of high-temperature gas: on the one hand, propellant gas production generates high-temperature, high-pressure gas, increasing the chamber pressure; on the other hand, the discharge of high-pressure gas through the nozzle decreases the pressure. The propellant gas production rate, the gas production area of ​​the propellant cross-section, and the gas generation rate together constitute the factors affecting the high-pressure chamber pressure. Among these, the propellant arrangement plays a crucial role—different propellant arrangements alter the propellant gas production trigger position and propagation path, affecting the time required for the entire propellant cross-section to be triggered, thus changing the high-pressure gas generation rate curve. In other words, different propellant geometric arrangements lead to differences in the rate of pressure rise and peak value within the high-pressure chamber, which is a key parameter determining the high-pressure chamber pressure level.

[0077] In summary, the main factors affecting the outlet flow rate per unit time of the gas-generating device are the high-pressure chamber pressure and the nozzle cross-sectional area; and the key factor affecting the high-pressure chamber pressure is the propellant arrangement (assuming the propellant properties and charge amount are constant). Therefore, the nozzle diameter and propellant arrangement become the core parameters determining the exhaust performance of the gas-generating device. This theoretical calculation stage, completed before the experiment, provides a scientific basis for the subsequent structural design and parameter selection of the gas-generating device, ensuring that the experimental scheme is well-founded.

[0078] Gas generation unit assembly stage

[0079] Based on the design parameters determined by theoretical calculations, the mechanical assembly of the gas generating unit 15 begins. Using components such as end caps, tanks, nozzles, and propellants as a foundation, the components are assembled into a complete gas generating unit according to a predetermined sequence. During assembly, special attention is paid to sealing (such as the installation of O-rings and gaskets) and the installation and arrangement of sensors to ensure that the assembled gas generating unit is reliably sealed and structurally robust.

[0080] Detailed description:

[0081] End Cap Assembly Pre-assembly and Sealing: The plug 4 and screw plug 3 are pre-installed onto the corresponding holes on the left side of the end cap 1 to seal the gas-generating orifice at the top of the end cap. The plug 4 is made of a highly malleable material to ensure reliable plugging; the plug 4 is then tightened onto the end cap using the screw plug 3. Subsequently, a ring of silicone rubber is applied around the screw plug hole left after tightening the screw plug 3 to enhance the seal. This sealing operation must be performed in advance, and the silicone rubber must be allowed to fully cure after application before proceeding with subsequent assembly steps.

[0082] Sensor Installation: Install a pressure sensor on the sensor base 14 pre-drilled on the upper right side of end cap 1. Before installation, place a ring-shaped silicone sealing gasket around the bottom of the sensor base, then tighten the pressure sensor onto the base to ensure a reliable seal at the sensor interface. This pressure sensor is used to monitor pressure changes in the high-pressure chamber of the gas production unit in real time.

[0083] Propellant assembly: According to the designed propellant arrangement scheme, several propellants 8 are assembled and fixed on a mounting plate 7, and secured with multiple small nuts 6 to ensure the propellant is firmly mounted on the mounting plate (for example, if a ring arrangement is used, the propellant is arranged in a ring around the mounting plate). This propellant-mounting plate assembly is pre-assembled and ready for use.

[0084] Propellant loading and securing: Place the retaining ring 9 into the appropriate position inside the tank 2 for positioning, then place the propellant assembly assembled in step 3 into the tank 2, positioning the propellant assembly tightly against the retaining ring. Next, insert the pressure ring 5 into the tank 2 and push it above the propellant assembly to press and secure it, preventing the propellant assembly from loosening or shifting inside the tank.

[0085] End cap closure and main seal: An O-ring 11 is placed in the O-ring groove 12 set at the opening edge of the tank body 2 as the main seal at the connection between the end cap and the tank body. Then, the end cap 1 is placed on the tank body 2, aligning the end cap flange with the tank body flange, and multiple sets of high-strength bolt assemblies 13 are used to tightly lock the end cap 1 and tank body 2 together. During the tightening of the bolts, symmetrical and even force should be applied to ensure a reliable and properly sealed connection between the end cap and the tank body. At this point, the high-pressure chamber of the gas generating device has been formed and basically sealed.

[0086] Nozzle Installation and Bottom Sealing: Install nozzle 10 onto the exhaust outlet flange at the bottom of tank 2. During installation, first check if there is a dedicated O-ring groove at the nozzle 10 flange interface, and place an O-ring of the appropriate size in the groove to ensure a seal at the nozzle-tank connection. Then, align the nozzle flange with the lower flange of the tank and tighten the nozzle to the tank with bolts. At the transition interface between the nozzle outlet and the external environment, a high-temperature resistant PTFE gasket is also inserted to further enhance the sealing and heat resistance of the nozzle interface. At this point, the assembly of the gas generating device 15 is complete, forming a high-pressure gas generating device internally filled with propellant, equipped with pressure sensing and a sealed nozzle.

[0087] Loading into the ship

[0088] The assembled gas generating device 15 is integrated and installed into the gas collection chamber 16 inside the vessel 18. The gas generating device is fixed to the vessel structure using bolts, ensuring a reliable connection between the gas generating device outlet and the gas collection chamber inlet. This ensures that the high-temperature, high-pressure gas can smoothly enter the gas collection chamber through the nozzle and then exit to the vessel surface through the exhaust port. During this stage, the airtightness of the connection between the gas generating device and the vessel must also be ensured to prevent high-pressure gas leakage.

[0089] Detailed description:

[0090] Disassembly of the hull section: Select the section on the hull 18 used to install the gas generating device 15 (this section has a pre-reserved gas collection chamber 16 and a gas generating device mounting base), disassemble and remove this section from the main body of the hull, exposing the internal mounting flange interface. This section is usually located in the upper middle part of the hull, close to the gas collection chamber area inside the hull.

[0091] Gas generating device placement and fixation: The assembled gas generating device 15 is moved into the hull section and aligned with the mounting flange. Multiple sets of high-strength bolts 13 are used to securely fasten the end cap flange of the gas generating device to the mounting flange of the hull section, ensuring reliable and secure fixation. This mounting flange directly connects to the gas collection chamber 16 inside the hull. After installation, the nozzle outlet of the gas generating device 15 is aligned and engaged with the inlet channel of the gas collection chamber.

[0092] Gas Path Connection and Sealing: After the gas generating device is fixed in place, its nozzle 10 outlet faces the gas collecting chamber 16 inlet, and a gas-tight connection is achieved through a PTFE gasket pre-placed between the two flanges. Thus, when the high-pressure gas generating device generates gas, the generated high-temperature, high-pressure gas will be ejected through the nozzle 10 and pass through the gasket into the gas collecting chamber 16. Subsequently, the high-temperature gas gathers in the gas collecting chamber and is discharged from the hull through multiple exhaust ports 17 opened around the shoulder of the hull 18, connecting with the external water body. The entire gas path connection ensures a smooth path for gas from the gas generating device to the outside of the hull, and prevents gas leakage through components such as O-rings and gaskets, ensuring that the high-temperature gas is discharged only from the exhaust ports.

[0093] The spacecraft is then reassembled: the spacecraft section with the gas-generating device installed is reconnected to the rest of the spacecraft. The sections are reassembled in the reverse order of disassembly, and the connecting bolts are tightened to restore the complete structure of spacecraft 18. At this point, the gas-generating device 15 is securely integrated into its designated position inside the spacecraft, and the internal gas path (high-pressure chamber → nozzle → gas collection chamber → exhaust port) is complete, laying the foundation for the next step of building the experimental system.

[0094] The construction phase of the experimental system for the aircraft

[0095] The complete vehicle body 18, equipped with the gas-generating device, is placed into a dedicated water-emergence experimental apparatus to construct the vehicle body water-emergence experimental system. This stage includes placing the vehicle body into a cylinder 20 supported by a base 23 and installing components such as a membrane 21, a sealing ring 22, and a power unit 19 to simulate the environment and initial conditions for the vehicle body to emerge from the water. Simultaneously, a high-speed camera system is deployed at the experimental site to record the entire process of the vehicle body emerging from the water and adjusting its attitude. This assembly stage ensures the integrity of the experimental hardware system and the proper sealing of all interfaces, preparing it for the formal experiment.

[0096] Detailed description:

[0097] Cylinder and base installation: The pre-placed base 23 in the experimental water tank (or trough) is fixed in the designated position, and then the transparent cylinder 20 is vertically installed on the base 23 and firmly fixed. The base provides support for the cylinder, keeping the cylinder 20 vertically stable. The interior of the cylinder will serve as a guide channel for the vehicle's outward movement and a container for a local vacuum environment.

[0098] Sealing ring installation: Install a sealing ring 22 at the position where it mates with the inner diameter of the cylinder 20 on the outer surface of the vessel 18. Fit the sealing ring 22 onto the corresponding diameter of the vessel and secure it to the outer shell using bolts. The sealing ring is made of elastic material and, after installation, should form a circumferential seal with the inner wall of the cylinder 20 to prevent leakage of water or gas from the inside or outside of the cylinder during the experiment, while also serving as a guide and support for the vessel.

[0099] The vehicle body is placed into the cylinder: The assembled vehicle body 18 is slowly lifted using a lifting device and lowered vertically into the opening of the cylinder 20, carefully inserting the vehicle body into the cylinder. During placement, ensure that the vehicle body remains centered and that the sealing ring 22 is in uniform contact with the inner wall of the cylinder. After the vehicle body is fully in place, its lower part should be aligned with or locked to the predetermined position of the base, so that the vehicle body is suspended inside the cylinder and ready to be propelled by the power unit.

[0100] Membrane sealing installation: Cover the top opening of cylinder 20 with a tearable membrane 21, covering and sealing the upper end of the cylinder. Use waterproof adhesive or foil tape to fix the membrane to the edge of the top opening of the cylinder, ensuring a tight seal. This membrane is used to simulate the separation between the vehicle and the outside water when it emerges from the water. Once the vehicle rises and breaks through the membrane, the space inside the cylinder will be connected to the outside water, and the vehicle will then enter the water. The membrane material should be of appropriate thickness, easily broken by the vehicle, and will not leave large fragments that affect movement after breaking.

[0101] Power unit installation: Install the power unit 19 (e.g., a catapult propulsion mechanism or compressed air drive) above the top of the cylinder 20. Typically, the power unit includes a piston or spring mechanism, which can be secured to the top flange of the cylinder using a high-strength bolt assembly. During installation, ensure the power unit is aligned with the axis of the launch vehicle 18 and reliably connected to the cylinder, allowing for effective power transmission to the launch vehicle. The function of the power unit 19 is to provide an initial upward thrust to the launch vehicle at the start of the experiment, causing it to accelerate upwards to complete the water exit maneuver. After installation and fixation, perform a functional check on the power unit (e.g., whether the piston slides smoothly, and whether the spring or air pressure is normal) to ensure proper triggering during the experiment.

[0102] High-speed camera system setup: Based on experimental observation requirements, a support frame for high-speed cameras 24 is erected outside the cylinder 20, and multiple high-speed cameras are installed to record the experimental process. Specifically, camera brackets are placed directly in front of and to the side (e.g., the left side) of the cylinder, with one or more high-speed cameras 24 mounted at different heights on each bracket, aimed at the area traversed by the vehicle as it emerges from the water. The viewing angle and focal length of each camera are adjusted to clearly capture the vehicle's motion after entering the water and the evolution of bubbles around the vehicle during the exhaust of the gas-generating device. The camera system is connected to a data acquisition device or control terminal to synchronously start recording during the experiment. After completing the camera system setup, the installation and sealing of all parts of the experimental system are checked. Once everything is confirmed to be correct, the next stage of the experiment can proceed.

[0103] Experimental execution phase

[0104] After the system was built, an out-of-water test was conducted on the entire experimental system. The system was lowered to the predetermined water depth and the initial conditions were adjusted (such as a negative pressure environment inside the cylinder). Then, each device was activated in sequence: first, the power unit propelled the vehicle 18 to accelerate upwards, simulating the high-speed out-of-water process of the vehicle; during the movement, cavitation occurred on the surface of the vehicle, which then triggered the gas generation device 15 to generate gas, which was then vented to the surface of the vehicle through the exhaust port to suppress cavitation and adjust the attitude. The entire process was recorded in real time by a high-speed camera 24. The attitude adjustment effect was evaluated based on the video results. If the expected results were not achieved, the parameters such as propellant arrangement and nozzle size were modified based on the video data and theoretical models, and the test was repeated until the ideal attitude control effect was obtained.

[0105] Detailed description:

[0106] Lowering and Pressure Adjustment: Using lifting equipment, the assembled water discharge test system is hoisted to the target water area and lowered to the designated water depth (e.g., to the depth to simulate water discharge at a certain depth). At this point, the cylinder 20 is subjected to a certain hydrostatic pressure. The vacuum pump is started to evacuate the inner cavity of the cylinder 20, creating a negative pressure environment inside the cylinder that is lower than the external water pressure. Evacuation continues until the pressure inside the cylinder drops to the initial pressure value required for the experiment (usually slightly lower than the external hydrostatic pressure to simulate the decompression conditions during water discharge). Then, the vacuum pump is turned off and the negative pressure is maintained for a period of time (pressure holding phase) to create the necessary initial conditions for the experiment.

[0107] The power unit is activated, and the vehicle accelerates upward: After confirming that all systems are ready, the experiment start command is issued through the control system. First, the power unit 19 at the top of the cylinder is triggered according to the set program, instantaneously releasing energy to the vehicle 18, pushing it upward from a stationary state. The vehicle is subjected to thrust from the bottom and rises rapidly along the internal track of the cylinder 20. The acceleration and initial velocity are determined by the design parameters of the power unit.

[0108] Breaking through the membrane and entering the water: Propelled by the power unit, the vehicle 18 impacts the membrane 21 at the top of the cylinder at high speed, quickly breaking the membrane and rushing out of the cylinder into the water above the cylinder. As the membrane ruptures, the negative pressure environment inside the cylinder connects with the external water area, and the vehicle officially completes the "emergence" action and begins to move freely and rise in the water.

[0109] Cavitation and Attitude Instability: During the high-speed ascent of the vehicle, its surface undergoes high-speed relative motion with the water, resulting in a local pressure reduction and a significant natural cavitation effect. Cavitation bubbles continuously form, grow, and irregularly detach and collapse on the surface of the vehicle, causing fluctuations in the hydrodynamic forces acting on it. This leads to instability in the vehicle's attitude in the water (deflection, vibration, etc.). At this point, the vehicle's attitude is difficult to control autonomously and tends to deviate from the predetermined trajectory, requiring timely attitude intervention.

[0110] Triggering the exhaust of the gas-generating device: When cavitation on the surface of the spacecraft is detected to reach a predetermined intensity, or when the spacecraft's attitude deviates beyond a threshold (which can be determined by detecting cavitation pressure pulsations or attitude change rate by sensors inside the spacecraft), the control system of the spacecraft 18 immediately sends a start command to the gas-generating device 15. Upon receiving the command, the gas-generating device generates gas, triggering the propellant 8 inside. The propellant rapidly decomposes and generates a large amount of high-temperature, high-pressure gas.

[0111] Gas is injected into and discharged from the gas collection chamber: The high-temperature, high-pressure gas generated in the gas generating device 15 is throttled and expanded by the nozzle 10, and injected into the gas collection chamber 16 inside the hull as a high-speed airflow. Due to the good sealing of the gas passage between the gas generating device and the gas collection chamber, this high-pressure airflow immediately fills the gas collection chamber and is evenly sprayed into the water outside the hull through the exhaust holes 17 around the hull. In a short time, a large amount of gas is released near the surface of the hull, forming a bubble layer around the shape of the hull.

[0112] Cavitation suppression and attitude adjustment: As gas is expelled, the water flow field around the vehicle changes. On the one hand, the expelled gas forms a gas film at the vehicle's boundary layer, isolating the water from direct contact with the vehicle's surface and significantly reducing the number of cavitation bubbles originally attached to the surface. On the other hand, the expulsion of gas also generates a certain reaction force on the vehicle, helping to correct attitude deviations. Under these combined effects, the cavitation effect that previously caused attitude instability is significantly suppressed, and the balance and stability of the vehicle's movement in water are improved. The venting and attitude adjustment process generally continues until propellant gas production is complete and production ceases.

[0113] High-speed camera monitoring and recording: Throughout the entire process of water emergence, cavitation generation, and attitude adjustment via gas production, 24 pre-positioned high-speed cameras were simultaneously activated to capture the vehicle's motion from multiple angles. The camera system recorded the entire process of the vehicle emerging from the cylinder, entering the water, undergoing cavitation, and changing its attitude after jet propulsion. After the experiment, playback of the high-speed images allowed for a direct observation of the differences in the vehicle's attitude and the distribution of surrounding cavitation bubbles before and after the intervention of the gas production device, providing detailed evidence for evaluating the attitude control effect.

[0114] Results Evaluation and Judgment: Based on the video data recorded by the high-speed camera, combined with necessary measurement data (such as pressure sensor data inside the gas generation device), the attitude adjustment effect of this experiment was analyzed and judged.

[0115] If the cavitation phenomenon on the surface of the vehicle is significantly reduced after ventilation and exhaust, and the vehicle's motion attitude in the water tends to be stable without large swaying or deflection, it indicates that the attitude adjustment effect of the gas generation device is significant and the attitude adjustment experiment is successful.

[0116] If the attitude of the aircraft remains unstable after venting, indicating that the air still has a strong influence on the aircraft, and that the aircraft's movement has significant deviations or even signs of instability, it means that the attitude adjustment effect of this ventilation was not ideal and the expected attitude control target was not achieved.

[0117] Scheme Improvement and Repeat Testing: When experimental results do not meet expectations, the parameter configuration of the gas-generating device needs to be adjusted based on the observation results, and the test needs to be repeated. Researchers will comprehensively analyze the attitude change characteristics of the vehicle recorded by high-speed cameras and the results predicted by theoretical calculation models to identify discrepancies and optimize the design of the gas-generating device accordingly. The adjustment scheme includes:

[0118] Increase the amount of propellant 8 in the gas generating device, or change the arrangement shape of the propellant (such as changing it from a ring shape to a crescent shape) to increase the total amount of gas produced or adjust the generation rate of high-pressure gas, thereby changing the exhaust duration and pressure curve.

[0119] A larger nozzle diameter of 10 is selected to increase the exhaust flow rate per unit time (releasing more gas faster, but correspondingly shortening the duration of a single exhaust and reducing the peak exhaust pressure).

[0120] A smaller nozzle diameter of 10 is selected to reduce the exhaust flow rate per unit time (slowing down the gas release rate, but increasing the pressure inside the cavity during exhaust and prolonging the exhaust time).

[0121] After adjustments were completed, the gas-generating device was reassembled and debugged, and the above experimental steps were repeated to conduct an attitude adjustment test on the vehicle after it emerged from the water. Through multiple iterative tests, parameters such as propellant arrangement and nozzle size were continuously optimized until experimental results showed that the attitude adjustment effect of the vehicle after it emerged from the water met the expected target.

[0122] Implementation Method 3: This implementation method further describes the technical solution provided above in detail through specific embodiments, specifically:

[0123] An experimental method for a gas-generating device used for adjusting the attitude of a vehicle emerging from the water. It includes: an end cap 1, a tank 2, a screw plug 3, a plug 4, a pressure ring 5, a small nut 6, a mounting plate 7, propellant 8, a retaining ring 9, a nozzle 10, an O-ring 11, an O-ring groove 12, a high-strength bolt assembly 13, and a sensor base 14. These are the components of the gas-generating device 15. In addition, there is a gas collection chamber 16, an exhaust port 17, a vehicle body 18, a power unit 19, a cylinder 20, a diaphragm 21, a sealing ring 22, a base 23, and a high-speed camera 24. First, the outlet flow rate of the exhaust port is estimated based on the attitude adjustment requirements of the vehicle emerging from the water experiment. According to the law of conservation of mass, the total outlet flow rate of all exhaust ports equals the inlet flow rate of the gas collection chamber and also equals the outlet flow rate of the gas-generating device. Therefore, only the outlet flow rate of the gas-generating device needs to be calculated. Dividing the outlet flow rate of the gas-generating device by the number of exhaust ports yields the outlet flow rate of a single exhaust port. Based on the calculation results, a suitable propellant and nozzle are selected. According to the gas continuity equation, the gas production flow rate is equal at any cross-section of the nozzle, and the throat is the critical interface where the gas velocity is exactly the speed of sound, i.e., Ma = 1. Based on the assumption that the flow of high-temperature, high-pressure gas in the high-pressure chamber throat is one-dimensional, quasi-steady, and isentropic, the high-pressure chamber outlet flow rate per unit time is... The expression is:

[0124]

[0125] Considering friction and heat loss, equation (1) needs to introduce a flow correction factor. but:

[0126]

[0127] In formula (2), and It is related to the performance of the propellant. Once the propellant is selected, and If all values ​​are constants, then the high-pressure chamber outlet flow rate per unit time is... It depends only on the high-pressure chamber pressure p1 and the throat area S t1 Adjust the throat area S t1 This can be achieved by selecting nozzles with different throat diameters; the larger the throat diameter, the higher the outlet flow rate of the high-pressure chamber per unit time. Next, we will analyze the factors affecting the pressure p1 in the high-pressure chamber.

[0128] Let the pressure in the high-pressure chamber of the gas generating device be p1, the temperature be T1, the gas constant be R, and the density of the high-temperature, high-pressure gas in the high-pressure chamber be ρ1. From the ideal gas law, we know that:

[0129] p1=ρ1RT1 (3)

[0130] Let the volume of the high-pressure chamber be V1, and the mass of the propellant be m.p The mass of the high-temperature, high-pressure gas generated in the high-pressure chamber within time t is m. b The high-pressure chamber outlet flow rate is m³ / s within time t. t1 The remaining high-temperature, high-pressure gas in the high-pressure chamber is the mass of high-temperature, high-pressure gas generated minus the mass of high-temperature, high-pressure gas flowing out. Therefore, we have:

[0131] ρ1V1=m b -m t1 (4)

[0132] Substituting equation (4) into equation (3), we get:

[0133]

[0134] According to the literature review, the filling rate of high-temperature and high-pressure gas per second is very small within the commonly used high-pressure chamber pressure range (less than 30 MPa) and can be ignored. Therefore, equation (5) can be directly differentiated with respect to time, and we have:

[0135]

[0136] As shown in formula (6), since the temperature T1, the gas constant R, and the high-pressure chamber volume V1 can all be approximated as constants, the factors affecting the pressure change in the high-pressure chamber are: the mass of high-temperature, high-pressure gas generated in the high-pressure chamber per unit time t is... The high-pressure chamber outlet flow rate per unit time is First, let's analyze... The expression is shown in formula (7):

[0137]

[0138] ρ p For propellant density, S b Let ρ be the propellant cross section, u be the gas production velocity, and ρ be the gas production velocity. p S b U and u are physical property parameters of the propellant. After the propellant is selected, all three are known constants. However, if the arrangement of the propellant is different, it will affect the triggering time of the propellant section. This is because when the arrangement of the propellant is different, the position of the triggering point will also change, and the distance between the triggering point and the propellant section will be different. Since the initiation gas velocity rate of the propellant is constant u1, the time t1 for the entire propellant section to be triggered will be different. In formula (7), S b This refers to the cross-sectional area when the propellant is fully ignited, although the S when the propellant is fully ignited... b It is a constant, but S at this time bIt is not a constant but a function related to the propellant initiation gas velocity rate u1 and the total triggering time t1. This function lacks a theoretical formula and can only be fitted using experimentally measured data. Assuming S... b If u1 and t1 are linear functions, then:

[0139] S b =u1t1 (8)

[0140] Then, by continuously refining formula (8) based on experimentally measured data, S can be finally obtained. b The approximate functional relationship between u1 and t1. This shows that the propellant arrangement affects... It is a key parameter, and also a key parameter affecting the pressure p1 in the high-pressure chamber.

[0141] As can be seen from the preceding analysis, the influence The key parameters are the high-pressure chamber pressure p1 and the throat area S. t1 When p1 increases, As can be seen from formula (6), when... As p increases, p1 decreases, and when p1 decreases, Decrease, and when Decreasing p1 increases p1, and this repeated coupling and mutual influence makes it difficult to analyze p1 and p1. The theoretical influence relationship can only be analyzed through experimental data to fit p1 and The functional relationship between them is not considered in this invention, therefore, this invention simplifies the process and does not take into account... The only key parameter affecting p1 is the propellant arrangement.

[0142] In summary, the factors affecting the high-pressure chamber outlet flow rate per unit time are... The key parameters are the high-pressure chamber pressure p1 and the throat area S. t1 The key parameter affecting the high-pressure chamber pressure p1 is the propellant arrangement, which in turn affects the high-pressure chamber outlet flow rate per unit time. The key factor is the laryngeal area S t1 And the arrangement of the propellant.

[0143] like Figure 1 As shown, the high-pressure chamber outlet flow rate per unit time can be calculated. The trend graph over time shows how the high-pressure chamber outlet flow rate can be adjusted per unit time by modifying the propellant arrangement. Adjustments were made to the propellant ring arrangement, such as... Figure 1 As shown in Figure a, the propellant is arranged in a crescent shape as follows: Figure 1 As shown in b, the high-pressure chamber outlet flow rate per unit time for the propellant annular arrangement is... The change curve is as follows Figure 1 As shown in c, the high-pressure chamber outlet flow rate per unit time for the propellant crescent-shaped arrangement is... The change curve is as follows Figure 1 As shown in d, compare Figure 1 c and Figure 1 As shown in d, the peak outlet flow rate is more prominent in the annular arrangement, but the peak duration is shorter than in the crescent-shaped arrangement. Both arrangements have their advantages. In addition, the nozzle diameter can be adjusted to change the high-pressure chamber outlet flow rate per unit time. The larger the throat diameter, the better. The larger the value, the smaller the value. Calculations should be performed based on actual working conditions during the experiment. If the experimental results do not meet the expected goals, the calculation results before the experiment and the high-speed camera shooting results after the experiment can be combined for overall analysis to obtain an experimental scheme that better meets actual needs.

[0144] like Figure 2 As shown, the trend of pressure p1 in the high-pressure chamber over time can be obtained through calculation. The pressure p1 in the high-pressure chamber can be adjusted by changing the propellant arrangement. (Comparison) Figure 2 a and Figure 2 As shown in b, the peak outlet pressure p1 is more prominent in the annular arrangement, but the peak duration is shorter than that in the crescent-shaped arrangement. Both arrangements have their advantages. A pressure sensor is installed in the high-pressure chamber, and the pressure data obtained from the sensor can be used to correct the high-pressure chamber pressure p1 variation curves for both arrangements. This allows for a correction of the high-pressure chamber pressure p1 calculation formula, making the subsequent high-pressure chamber pressure p1 calculation results closer to the experimental value. It also improves the high-pressure chamber outlet flow rate. It is closer to the experimental values, the entire set of calculation formulas is more accurate, and it has higher value for engineering applications.

[0145] The high-pressure chamber outlet flow rate was obtained through calculation. By comparing the trend chart with the exhaust effect of the exhaust port captured by the high-speed camera, the outlet flow rate of the high-pressure chamber can be determined. There is an intuitive understanding that the attitude adjustment of a vehicle in water can also be quantitatively analyzed to achieve more precise adjustment targets.

[0146] like Figure 3As shown, the gas generation device 15 for the water emergence test of the hull 18 is assembled. First, the plug 4 and the screw plug 3 are installed in the reserved position on the left side of the end cover 1. The plug 4 is made of a plastic material and is used to seal the upper inlet of the end cover 1. Tighten the screw plug 3 to fix the plug 4. Tighten the screw plug 3 to fix the plug 4. Apply silicone rubber to the screw plug hole for sealing. This step needs to be done in advance. After the silicone rubber has completely cured, the subsequent operations can be carried out. Then, the pressure sensor is installed on the sensor base 14 on the upper right side of the end cover 1. Before installation, an annular silicone pad needs to be placed at the bottom of the base to ensure sealing. Then, several propellants 8, mounting plates 7, and small nuts 6 are assembled together. Next, the retaining ring 9, the assembly of propellants 8, mounting plates 7, and small nuts 6, and the pressure ring 5 are installed into the tank body 2. Then, the O-rings are installed into the groove of the tank body 2. The end cap 1 is covered, and the end cap 1 and the tank body 2 are locked with the high-strength bolt assembly 13. Finally, the nozzle 10 is installed under the tank body 2. There is a groove around the nozzle 10 for installing O-rings. The O-rings are installed in the groove, and a polytetrafluoroethylene gasket is placed under the tank body. At this time, the gas generating device 15 is assembled.

[0147] like Figure 4 As shown, the gas generating device 15 is located approximately in the upper middle position inside the vessel 18, above which is the gas collecting chamber 16. The exhaust port 17 of the gas collecting chamber is located approximately on the shoulder of the vessel. Figure 4 The gas generating device 15 is installed into the hull 18. First, the section of hull 18 with the gas generating device 15 mounting flange is disassembled. Then, the assembled gas generating device 15 is installed onto the flange using high-strength bolts. This flange is integral with the gas collection chamber 16 inside the hull 18. The high-temperature, high-pressure gas generated by the gas generating device 15 can pass through the nozzle 10, through the PTFE gasket, and then through the mounting flange to reach the gas collection chamber 16. Finally, it is discharged from the gas collection chamber 16 to the outside through the exhaust ports 17 circumferentially around the hull 18. After the gas generating device 15 is installed, the section of hull 18 with the gas generating device 15 is combined with the other parts of the hull 18 to form a complete hull 18.

[0148] like Figure 5 As shown, the water-launching test system of the aircraft includes a power unit 19, a cylinder 20, a membrane 21, a sealing ring 22, and a base 23. In addition, it includes a high-speed camera system. Figure 5 The water-launch test system for the vehicle body 18 is shown. First, the cylinder 20 is installed on the base 23. Then, the sealing ring 22 is installed on the vehicle body 18 and fixed with bolts. Next, the vehicle body 18 is installed into the cylinder 20 by hoisting. The membrane 21 is then attached to the top of the cylinder 20. Finally, the power unit 19 is installed on the cylinder 20 and locked with a high-strength bolt assembly.

[0149] like Figure 6 and Figure 7As shown, high-speed cameras 24 are located directly in front of and to the left of the movement path of the vehicle 18, with multiple high-speed cameras 24 arranged at different heights in both directions. Figure 6 and Figure 7 As shown, a high-speed camera system is set up. First, a frame for installing a high-speed camera 24 is set up in front of and to the left of the cylinder 20. According to the shooting requirements of the water exit experiment, multiple high-speed cameras 24 are set up at different heights on the frame to shoot the posture of the vehicle when it moves in the water. At this time, the entire water exit experiment system is assembled.

[0150] Finally, the water exit test of vehicle 18 is conducted. Based on the required water depth for the water exit test of vehicle 18, the entire water exit test system is lowered to the target water depth, and the vacuum pump is started to create negative pressure. When the ambient pressure drops to the target test pressure, pressure is maintained. At this point, the water exit test of vehicle 18 can be conducted. A start command is issued through the external control system. First, the power unit 19 starts working, and then vehicle 18 moves upward under the thrust from its bottom, breaking through the membrane 21 at the top of the cylinder and entering the water. It continues to move in the water, at which point natural cavitation occurs on the surface of vehicle 18, making its underwater movement unstable and difficult to control. At this time, the control system of vehicle 18 sends a start command to the gas generating device 15, which begins to generate gas. The generated gas is discharged to the outer surface of the vehicle through the gas collection chamber 16 and the exhaust port 17. The gas generation process can be captured by the high-speed camera 24, which is used to judge the effect of the underwater movement attitude adjustment of vehicle 18. If the natural cavitation effect after exhaust has little impact on the attitude of vehicle 18, and the vehicle 18 moves relatively stably, it indicates that the attitude adjustment is successful. If the natural cavitation effect after exhaust still has a significant impact on the attitude of the vehicle 18, and the vehicle 18's motion attitude is unstable, it indicates that the attitude adjustment effect is not good. It is necessary to adjust the amount of propellant 8 in the gas generation device 15. The more propellant 8 there is, the greater the gas production, and vice versa. Alternatively, the throat diameter of the nozzle 10 can be adjusted. The larger the throat diameter of the nozzle 10, the greater the exhaust flow, the lower the exhaust pressure, and the shorter the exhaust time. Conversely, the smaller the throat diameter, the lower the exhaust flow, the higher the exhaust pressure, and the longer the exhaust time. The specific adjustment plan needs to be formulated based on the underwater motion attitude of the vehicle 18 captured by the high-speed camera 24, and then the experiment should be repeated.

[0151] like Figure 8 The diagram shows the experimental process of an air-generating device 15 for adjusting the water exit attitude of a vehicle 18 according to the present invention.

[0152] In summary, this invention enables the production of a relatively large amount of high-temperature, high-pressure gas through a small-volume, high-strength, and well-sealed gas-generating device 15. This gas is then discharged to the outer surface of the vehicle body 18 through the exhaust port 17 of the gas collection chamber 16 within the vehicle body 18, thereby achieving attitude adjustment in water and maintaining stability during underwater movement. If the attitude adjustment effect is unsatisfactory, the amount of propellant 8 within the gas-generating device 15 can be adjusted, or the throat diameter of the nozzle 10 can be adjusted, and the experiment can be repeated. Adjusting the amount of propellant 8 and the throat diameter of the nozzle 10 expands the application range of the entire vehicle body 18 underwater experimental system, meeting the multi-condition requirements for adjusting the underwater movement attitude of the vehicle body 18. This invention has significant practical engineering value.

[0153] The above description of several specific embodiments further details the technical solution provided by the present invention in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An experimental method for a gas-generating device used for adjusting the attitude of a vehicle emerging from the water, characterized in that, include: The steps involve deriving theoretical thermohydrodynamics and the jet flow equation, calculating and obtaining the functional relationship between the jet cross-sectional area and the internal pressure of the high-pressure gas chamber; the functional relationship between the jet cross-sectional area and the internal pressure of the high-pressure gas chamber is as follows: High-pressure chamber outlet flow rate per unit time The expression is: In the formula: and It is related to the performance of the propellant. Once the propellant is selected, and If all values ​​are constants, then the high-pressure chamber outlet flow rate per unit time is... It depends only on the pressure in the high-pressure chamber. and throat area ; Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber, combined with the geometric arrangement model of the propellant (which is annular or crescent-shaped), the steps of deriving the law of change of the propellant gas production area with time and establishing the gas production rate model are as follows. The steps for predicting the exhaust characteristics of the gas chamber are to calculate the process of pressure change over time in the high-pressure gas chamber and the exhaust parameters of the nozzle by using the gas production velocity model and gas production evolution law. The steps involve collecting high-pressure chamber pressure and exhaust flow data during the actual exhaust process, comparing and analyzing the experimental data with the predicted results, and correcting the parameters of the propellant arrangement model and pressure prediction model based on the feedback of the differences. The change in the propellant gas production area over time is based on the gas production initiation surface determined by the propellant arrangement and the propagation path. A linear fitting model is used to initially estimate the propellant gas production and deployment process.

2. The experimental method for a gas-generating device for adjusting the water-emerging attitude of a vehicle according to claim 1, characterized in that, The functional relationship between the cross-sectional area of ​​the nozzle and the internal pressure of the high-pressure air chamber is established based on the principle of gas continuity and the assumption of one-dimensional isentropic flow, wherein the airflow velocity at the nozzle is equal to the speed of sound.

3. The experimental method for a gas-generating device for adjusting the water-emerging attitude of a vehicle according to claim 1, characterized in that, The gas production rate model is based on preset constant parameters according to the propellant type, and uses the gas production area to make a preliminary estimate of the gas production mass per unit time.

4. The experimental method for a gas-generating device for adjusting the water-emerging attitude of a vehicle according to claim 1, characterized in that, The pressure change inside the high-pressure gas chamber is estimated using an ideal gas state model, and a dynamic balance solution is obtained by combining the cumulative mass of the high-temperature and high-pressure gas with the discharge flow rate.

5. The experimental method for a gas-generating device for adjusting the water-emerging attitude of a vehicle according to claim 1, characterized in that, The experimental data includes pressure curves of the high-pressure chamber collected by pressure sensors and a sequence of images of the evolution of exhaust bubbles captured by a high-speed camera system.

6. An experimental system for a gas-generating device used for adjusting the attitude of a vehicle emerging from the water, characterized in that, The experimental system is used to implement the experimental method described in claim 1. The experimental system includes: a module that calculates and obtains the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber by deriving theoretical thermohydrodynamics and the nozzle flow equation; a module that, based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas chamber, and combined with the propellant geometric arrangement model, derives the law of change of the propellant gas production area over time and establishes a gas production velocity model; a module that calculates the process of pressure change over time in the high-pressure gas chamber and nozzle exhaust parameters through the gas production velocity model and gas production evolution law, and predicts the gas chamber exhaust characteristics; and a module that collects high-pressure gas chamber pressure and exhaust flow data during the actual exhaust process, compares and analyzes the experimental data with the predicted results, and corrects the parameters of the propellant arrangement model and pressure prediction model based on the difference feedback.

7. A computer storage medium for storing computer programs, characterized in that, When the computer program is read by the computer, the computer executes the method of claim 1.

8. A computer, comprising a processor and a storage medium, characterized in that, When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 1.

9. A computer program product, as a computer program, is characterized by: When the computer program is executed, it implements the method of claim 1.

Images