Experimental method of gas production device for adjusting water outlet posture of navigation body

Abstract

The invention discloses an experimental method of a gas production device for adjusting the water outlet posture of a navigation body, and relates to the technical field of water outlet navigation body model experiments. In order to solve the technical defect of inaccurate control of a high-pressure air source in an existing experimental method for attitude adjustment requirements under a complex water outlet working condition in the prior art, the technical scheme provided by the invention comprises the following steps: calculating and obtaining a function relationship between the sectional area of a spray throat and the internal pressure of a high-pressure air cavity; in combination with the geometric arrangement model of the propellant, deducing the rule that the gas production area of the propellant changes along with time, and establishing a gas production speed model; predicting the exhaust characteristics of the air cavity; high-pressure air cavity pressure and exhaust flow data in the actual exhaust process are collected through experiments, experimental data and prediction results are compared and analyzed, and parameters of the propellant arrangement model and the pressure prediction model are corrected according to difference feedback. The device is suitable for experiment research related to attitude adjustment and cavitation suppression in the high-speed water outlet process of the navigation body.

Description

Technical Field

[0001] The invention relates to the technical field of water-emerging vehicle model experiments, and in particular to an experimental method of a gas-generating device for adjusting the water-emerging vehicle posture. Background Art

[0002] With the development of high-speed vehicle technology, attitude stability during water exit has become a key issue in research and engineering practice. When a vehicle moves at high speed in water, large areas of natural cavitation form on its surface. The generation, development, and collapse of cavitation bubbles cause violent fluctuations in the flow field, which in turn subjects the vehicle to complex nonlinear hydrodynamic loads, significantly affecting its attitude control accuracy and motion stability, and may even cause motion instability. To address this issue, researchers have proposed a surface ventilation technology to suppress cavitation. By discharging gas onto the outer surface of the vehicle to regulate the local flow field, the cavitation effect is mitigated and attitude adjustment is achieved.

[0003] At present, ventilation and attitude adjustment technology mainly relies on the stable output of high-temperature and high-pressure gas from the gas source device and the precise control of the exhaust process. Research focuses on aspects such as the gas source control method, the compactness of the device structure, and the compatibility of the internal space. A typical research result, such as the patent with publication number CN109596313B, proposes an active ventilation experimental device based on a whole air chamber. It uses an external air pressure system to inflate the air storage cavity inside the vehicle and uses a control system to release gas on demand to adjust the attitude. However, the whole air chamber structure in this technology is huge and occupies a large amount of internal space, which limits the layout of other measurement and control units. In addition, the air storage cavity structure is limited by strength and sealing performance, and cannot meet the needs of high-frequency, high-pressure and rapid exhaust.

[0004] Another device, embodied in patent publication number CN203732238U, integrates the air storage tank with the hull structure. By incorporating a "truncated cone-shaped tank," it improves overall strength and air storage capacity while minimizing the encroachment on internal space. While this design has made progress in structural optimization, it still relies on an external air source for inflation, resulting in complex pre-experimental preparation and a cumbersome operational process. Furthermore, the air source control accuracy is limited, making it difficult to meet the engineering requirements for real-time dynamic adjustment of the high-speed out-of-water posture.

[0005] In summary, the following problems generally exist in the prior art:

[0006] The gas storage device is large in size and significantly occupies the limited space inside the vehicle;

[0007] The structural strength and sealing of the gas storage tank are difficult to achieve, and it cannot meet the requirements of high-temperature and high-pressure gas production;

[0008] The system relies on external gas source for gas supply, which is cumbersome to operate and has low degree of automation;

[0009] There is a lack of dynamic control mechanism for the high-pressure gas output rate and exhaust process, and the posture adjustment effect is limited.

[0010] Therefore, it is urgent to propose an experimental method with a compact structure, high integration, adjustable gas escape parameters, and suitable for attitude adjustment requirements under complex water discharge conditions, so as to solve the problems existing in the existing technology, such as inaccurate high-pressure gas source control, complex coupling relationship between gas production and exhaust capacity, and difficult integration of experimental equipment. Summary of the Invention

[0011] In order to solve the technical defects in the existing technology, the existing experimental methods for attitude adjustment under complex water discharge conditions have the following problems: inaccurate high-pressure gas source control, complex coupling relationship between gas production and exhaust capacity, and difficult integration of experimental devices. The technical solution provided by the present invention is as follows:

[0012] An experimental method for an air-generating device for adjusting the attitude of a navigation body out of water comprises:

[0013] The steps of calculating and obtaining the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity by deriving theoretical thermal fluid dynamics and nozzle flow equations;

[0014] Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity, combined with the geometric arrangement model of the propellant, the law of the change of the propellant gas production area over time is deduced, and a gas production velocity model is established;

[0015] The steps of predicting the cavity exhaust characteristics are as follows: calculating the pressure change process of the high-pressure cavity over time and the nozzle exhaust parameters through the gas production velocity model and gas production evolution law;

[0016] The high-pressure gas cavity pressure and exhaust flow data during the actual exhaust process are collected experimentally, the experimental data are compared and analyzed with the predicted results, and the parameters of the propellant layout model and the pressure prediction model are corrected based on the difference feedback.

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

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

[0019] Furthermore, a preferred embodiment is provided, wherein the gas production rate model presets constant parameters according to the propellant type, and makes a preliminary estimate of the gas production mass per unit time 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 cavity is estimated using an ideal gas state model, and a dynamic balance solution is performed in combination with the accumulated mass of the high-temperature and high-pressure gas and the exhaust flow rate.

[0021] Furthermore, a preferred embodiment is provided, wherein the experimental data includes a high-pressure chamber pressure curve collected by a pressure sensor and an exhaust bubble evolution image sequence captured by a high-speed camera system.

[0022] An experimental system for a gas generating device for adjusting the attitude of a navigation body out of water is also provided, comprising:

[0023] A module that calculates and obtains the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity by deriving theoretical thermal fluid dynamics and nozzle flow equations;

[0024] 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 layout model of the propellant, the law of the change of the propellant gas production area over time is derived, and a gas production velocity model module is established;

[0025] A module that calculates the time-varying process of the pressure in the high-pressure gas chamber and the exhaust parameters of the nozzle through the gas production velocity model and the gas production evolution law, and predicts the gas chamber exhaust characteristics;

[0026] The module collects the high-pressure air chamber pressure and exhaust flow data during the actual exhaust process through experiments, compares and analyzes the experimental data with the predicted results, and corrects the parameters of the propellant layout model and pressure prediction model based on the difference feedback.

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

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

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

[0030] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0031] By theoretically modeling and calculating the coupling relationship between propellant placement and nozzle parameters, predictable control of the high-temperature, high-pressure gas output flow and pressure is achieved. Compared to existing methods that rely on empirical adjustments or fixed gas source structures, this method can predict 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 use of a replaceable nozzle structure and modular propellant layout design makes it efficient and flexible to adjust gas production and exhaust flow. Traditional devices such as CN109596313B have a highly closed structure and are difficult to modify, making it difficult to quickly adapt to different experimental needs. However, this solution allows for rapid changes in gas output characteristics by replacing nozzles with different throat diameters or adjusting the propellant distribution shape (such as annular and crescent shapes), adapting to complex and changing working conditions.

[0033] The gas production device is encapsulated in a compact, high-strength tank, utilizing an O-ring groove seal and a polytetrafluoroethylene gasket to effectively enhance the sealing and pressure resistance of the gas production chamber. Compared to the "truncated cone-shaped cabin" solution proposed in CN203732238U, this invention significantly reduces space usage, improves internal space utilization, and provides structural margin for installing other test systems or control units.

[0034] By integrating pressure sensors into the gas production unit and calibrating them using theoretical models and real-time pressure measurement results, we can obtain pressure and flow curves that closely resemble actual operating conditions after the experiment, thereby optimizing design parameters. This data feedback mechanism complements existing passive testing methods and enhances the closed-loop control capabilities and repeatability of the experimental system.

[0035] High-speed camera systems positioned on the front and left sides of the vehicle enable simultaneous multi-angle capture of attitude changes, providing visual evidence for experimental result analysis and attitude adjustment effectiveness assessment. Compared to existing methods that rely on limited sensor locations for data acquisition, this solution enables visual analysis of the entire process, facilitating identification of cavitation effects and sources of attitude instability, thereby advancing attitude adjustment strategies from qualitative assessment to quantitative optimization.

[0036] The system supports repeated iteration of propellant placement and nozzle parameters based on experimental results. By adjusting the nozzle diameter or the amount and distribution of propellant, fine-grained control of the gas production rhythm and exhaust pulse is achieved. This multivariable joint adjustment mechanism can be extended to meet the requirements of vehicle attitude control under various speeds, depths, and load conditions, significantly improving the adaptability and engineering value of the experimental device.

[0037] It is suitable for experimental research on attitude adjustment and cavitation suppression during high-speed water exit of a vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 a is a schematic diagram of the annular arrangement of propellants;

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

[0040] Figure 1c is the outlet flow rate variation trend diagram of the propellant annular arrangement;

[0041] Figure 1 d is the outlet flow rate variation trend diagram of the propellant crescent arrangement;

[0042] Figure 2 a is the pressure change trend diagram of the high-pressure chamber in the propellant annular arrangement;

[0043] Figure 2 b is the pressure variation trend diagram of the high-pressure chamber in the crescent-shaped arrangement of propellants;

[0044] Figure 3 This is a schematic diagram of the gas production device;

[0045] Figure 4 Schematic diagram of the navigation body;

[0046] Figure 5 This is a schematic diagram of the navigation body out of water test system;

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

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

[0049] Figure 8 It is a workflow diagram.

[0050] Among them, the end cover 1; the tank body 2; the screw plug 3; the plug 4; the pressure ring 5; the small nut 6; the mounting plate 7; the propellant 8; the retaining ring 9; the nozzle 10; the O-ring 11; the O-ring groove 12; the high-strength bolt assembly 13; the sensor base 14; the gas generating device 15; the gas collecting chamber 16; the exhaust hole 17; the navigation body 18; the power device 19; the cylinder 20; the film 21; the sealing ring 22; the base 23; and the high-speed camera 24. DETAILED DESCRIPTION

[0051] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0052] Embodiment 1: This embodiment provides an experimental method for an air-generating device for adjusting the posture of a vehicle emerging from the water, comprising:

[0053] The steps of calculating and obtaining the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity by deriving theoretical thermal fluid dynamics and nozzle flow equations;

[0054] Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity, combined with the geometric arrangement model of the propellant, the law of the change of the propellant gas production area over time is deduced, and a gas production velocity model is established;

[0055] The steps of predicting the cavity exhaust characteristics are as follows: calculating the pressure change process of the high-pressure cavity over time and the nozzle exhaust parameters through the gas production velocity model and gas production evolution law;

[0056] The high-pressure gas cavity pressure and exhaust flow data during the actual exhaust process are collected experimentally, the experimental data are compared and analyzed with the predicted results, and the parameters of the propellant layout model and the pressure prediction model are corrected based on the difference feedback.

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

[0058] The temporal variation pattern of the propellant gas production area is based on the gas production starting surface and the propulsion propagation path determined by the propellant arrangement, and a linear fitting model is used to initially estimate the propellant gas production expansion process.

[0059] The gas production rate model presets constant parameters according to the propellant type and makes a preliminary estimate of the gas production mass per unit time in combination with the gas production expansion area.

[0060] The pressure change in the high-pressure gas cavity is estimated using an ideal gas state model, and a dynamic balance solution is performed based on the accumulated mass and exhaust flow rate of the high-temperature and high-pressure gas.

[0061] The experimental data include a high-pressure chamber pressure curve collected by a pressure sensor and an exhaust bubble evolution image sequence captured by a high-speed camera system.

[0062] Implementation Method 2: This implementation method further describes Implementation Method 1 in detail. Specifically:

[0063] In the Devices section:

[0064] Figure 1 Figure a is a schematic diagram of a propellant annular arrangement, where 7 is a mounting plate and 8 is a propellant. As can be seen, in the annular arrangement, multiple propellants 8 are evenly distributed on the mounting plate 7 in a circular arrangement, forming a nearly annular charge layout around the center of the mounting plate. The propellants 8 are symmetrically placed along the circumference, and the overall structure is balanced to ensure that high-pressure gas is evenly generated and distributed within the high-pressure chamber after gas production. The mounting plate 7 supports and positions the propellants, and is typically provided with fixing holes or bosses to secure the propellants in place using fasteners such as small nuts, thereby preventing the propellants from shifting before gas production.

[0065] Figure 1 b is a schematic diagram of a crescent-shaped propellant arrangement. In the crescent-shaped arrangement, the distribution of the propellant 8 on the mounting plate 7 is locally concentrated, mainly located on one side of the mounting plate, and the overall shape is similar to a portion of a circular ring (crescent). This arrangement makes the propellant 8 not completely symmetrically distributed in space, but forms a state where one side is dense and the other side is relatively empty on the mounting plate 7. Under the crescent-shaped arrangement, the concentration of the propellant in the high-pressure chamber is different from that of the annular arrangement. Its function is to extend the duration of gas production and obtain gas output for a longer period of time (correspondingly, the peak pressure is slightly lower, but it lasts longer). The two arrangements affect the pressure and flow output characteristics of the gas production device by changing the spatial distribution of the propellant 8 in the high-pressure chamber. Each has its own advantages, and a suitable propellant layout scheme can be selected according to experimental requirements.

[0066] like Figure 3The figure shows a schematic diagram of the longitudinal cross-section structure of the gas production device 15. In the figure, 1 is the end cover, 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 cover 1 is firmly connected to the tank body 2 through multiple groups of high-strength bolt assemblies 13, sealing the top of the tank body into a high-pressure gas production chamber (an O-ring 11 is provided at the junction of the end cover and the tank body, and is embedded in the O-ring groove 12 to ensure airtightness). The end cover 1 is provided with a through-hole for installing the gas production 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 cover 1; after the screw plug 3 is tightened, the pores of the plug are coated with silicone rubber to further ensure the seal. A sensor base 14 is located at the upper right corner of the end cap 1 for mounting measuring elements such as pressure sensors. When installing the sensor, a circular silicone pad is placed at the bottom of the base 14 to ensure a secure seal between the sensor and the high-pressure chamber. Inside the tank 2 of the gas generator 15, several propellant blocks 8 are assembled and secured together using a mounting plate 7 and a small nut 6. Specifically, the mounting plate 7 features a through hole or column for the propellant. The propellant 8 is then fitted onto the mounting plate and locked in place by the small nut 6, thereby securely stacking the propellant blocks together. When placed within the tank 2, the propellant assembly is positioned and held in place by a retaining ring 9. A pressure ring 5 is positioned above the retaining ring to apply a preload, compressing the propellant assembly from above and maintaining its stability within the tank. A nozzle 10 is connected to the lower end of the tank 2. The nozzle has a constricted throat to control the flow rate of the high-temperature gas generated. A circular O-ring groove 12 surrounds the nozzle 10, containing an internal O-ring 11 to ensure a tight seal between the nozzle and downstream components. In addition, a thin polytetrafluoroethylene gasket (high-temperature resistant gasket) is placed at the connection between tank 2 and the internal gas collection chamber of the subsequent vehicle to prevent high-temperature gas leakage and provide thermal insulation and buffering. When the above components are assembled as shown, the 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 eject the generated gas in a targeted manner through the nozzle 10 at the bottom.

[0067] like Figure 4As shown, the gas generator 15 is installed below the plenum 16 within the vehicle 18. In the figure, 15 represents the gas generator, 16 represents the plenum, 17 represents the exhaust port, and 18 represents the vehicle. The gas generator 15 is located roughly in the upper-center portion of the vehicle 18, directly above the plenum. A flange interface for mounting the gas generator 15 is prefabricated on the corresponding compartment of the vehicle 18 (this flange is integral with the plenum 16 within the vehicle). The gas generator 15 is secured to this flange using a high-strength bolt assembly, ensuring precise alignment between the outlet of the gas generator's nozzle 10 and the inlet flange of the plenum 16. During installation, a gasket (such as a polytetrafluoroethylene gasket) is placed between the nozzle 10 and the flange interface. This gasket, along with the O-ring 11 surrounding the nozzle, ensures a tight seal and insulation between the connection between the gas generator 15 and the plenum 16. The high-temperature, high-pressure gas generated by the gas generator 15 is ejected through the nozzle 10 and directly into the plenum 16 above the vehicle 18. The gas collecting chamber 16 is equivalent to a buffer chamber, which is connected to the outside world through a number of exhaust holes 17 on the shell of the vehicle. These exhaust holes 17 are evenly distributed along the circumference of the vehicle 18 (i.e. around its shoulder position). Therefore, after the high-pressure gas enters the gas collecting chamber 16 from the gas producing device 15, it will be evenly discharged from the vehicle along the multiple exhaust holes 17 around the outer shell of the vehicle 18 to achieve ventilation of the surface of the vehicle. After the gas producing device 15 is installed, the vehicle compartment equipped with the device is reconnected and combined with the rest of the vehicle 18 to restore the complete vehicle structure. Through the above installation, the gas producing device 15, the gas collecting chamber 16 and the exhaust holes 17 together constitute a continuous gas production channel, through which the high-temperature gas is guided from the inside of the vehicle to the outside, providing the vehicle with the airflow required for attitude control.

[0068] like Figure 5Figure 1 shows a schematic diagram of the structure of the vehicle exiting the water test system. In the figure, 18 represents the vehicle, 20 represents the cylinder, 21 represents the membrane, 22 represents the sealing ring, 23 represents the base, and 19 represents the power unit. Cylinder 20 is vertically mounted on base 23, forming a cylindrical test chamber that accommodates vehicle 18 and the water medium. Vehicle 18 is inserted into cylinder 20 from above by hoisting, with its outer diameter sealed against the inner diameter of cylinder 20 by sealing ring 22. Sealing ring 22 is fixed to the outer surface of vehicle 18 and secured with bolts, forming a watertight sliding interface between the vehicle and the inner wall of the cylinder. Once the vehicle is placed within the cylinder and the sealing ring is in place, a membrane 21 is adhered to the top opening of cylinder 20. This membrane 21, a thin, easily breakable sheet of material, acts as a diaphragm to simulate the water surface or the upper boundary of the closed chamber, and can be broken by the upward motion of vehicle 18. After the film is applied to the top of the cylinder, the power unit 19 is installed and connected to the cylinder 20 and fastened with a high-strength bolt assembly. The power unit 19 can be, for example, a catapult mechanism, a compressed air drive device or other mechanism that provides thrust, installed under the cylinder 20 (or connected to the base 23) to apply an upward thrust to the bottom of the vehicle 18. In the entire experimental system, the base 23 provides support, the cylinder 20 simulates a pool or a launch tube, and the vehicle 18 is placed therein to prepare for the upward movement. The film 21 simulates the initial closed conditions of the water surface, and the power unit 19 provides the initial velocity and energy required for the vehicle to emerge from the water. The various components are connected by bolts and sealing elements to ensure the rigidity and airtightness of the system. After the assembly is completed, preparations for the vehicle's water exit test can be carried out.

[0069] like Figure 6 and Figure 7 As shown, the vehicle exiting the water experiment also includes a high-speed camera shooting system for recording the vehicle's motion posture and gas production effect. Figure 6 This is a schematic diagram of the front view of the high-speed camera system, where 18 is the vehicle and 24 is the high-speed camera. A support frame for the high-speed camera 24 is set up directly in front of the movement path of the vehicle 18, and multiple high-speed cameras are installed on it at different heights. These cameras are arranged in layers along the vertical direction, so that their lenses are respectively aimed at different heights that the vehicle 18 may pass through, and images of the posture changes of the vehicle during the process of emerging from the water are obtained from the front. The multiple high-speed cameras in the front work together to record the movement of the water-facing surface of the vehicle 18 and the changes in the effect of gas production to suppress cavitation during the entire process of the vehicle 18 emerging from the water and rising.

[0070] Figure 7The diagram below shows the top view of the high-speed camera system (from a top view angle). The circle 18 indicates the position of the cross section of the vehicle, and 24 is a high-speed camera. It can be seen that a high-speed camera 24 is also arranged on the left side (side direction) of the vehicle 18's movement path to shoot the vehicle's movement from the side. The camera on the left side is installed on another supporting frame, and multiple cameras are also arranged at different heights to record the vehicle 18's movement posture in the water and in the water from a side view angle. Figure 6 and Figure 7 The two vertically arranged high-speed camera arrays in front and on the side shown can simultaneously obtain the front and side images of the movement of the vehicle 18, and can comprehensively observe the adjustment effect of the gas production device 15 on the posture of the vehicle, providing multi-angle data support and analysis basis for the experiment.

[0071] Theoretical calculation stage

[0072] First, theoretical calculations were performed to determine the exhaust flow rate required for the vehicle's attitude adjustment, and key parameters such as the propellant layout and nozzle diameter were selected accordingly. The calculation process, based on the gas continuity equation and one-dimensional isentropic flow theory, deduced that the main parameters affecting the outlet flow of the high-pressure gas cavity (the high-pressure chamber of the gas production device) are the cavity pressure and the nozzle cross-sectional area. The effect of the propellant layout on the cavity pressure was also analyzed, clarifying that the propellant gas production rate, cross-sectional gas production area, and gas generation rate are the key factors determining the high-pressure chamber pressure. These theoretical calculation results provide a prerequisite for the structural design and parameter selection of the experimental device.

[0073] Detailed description:

[0074] Based on the required operating conditions for the vehicle's exit-water attitude adjustment, estimate the required total exhaust flow rate from the exhaust ports. The law of conservation of mass indicates that the total exhaust volume from all exhaust ports equals the inlet flow rate of the plenum chamber 16, which in turn equals the outlet flow rate of the gas generator 15. Therefore, first calculate the outlet flow rate of the gas generator and divide this flow rate by the number of exhaust ports to obtain the required unit flow rate for each exhaust port. Based on these calculations, preliminarily select the propellant type and layout that meet the requirements, as well as the corresponding nozzle throat diameter.

[0075] Using the gas continuity equation and one-dimensional isentropic flow theory, the process of gas discharge from the high-pressure chamber of a gas production device through the nozzle was analyzed. At the narrowest point of the nozzle (the nozzle throat), the airflow reaches a critical state (the velocity reaches the speed of sound). The high-temperature gas flow rate through the nozzle throat per unit time is primarily determined by the gas pressure within the high-pressure chamber and the cross-sectional area of ​​the nozzle throat. Since the gas production parameters of a specific propellant (such as the gas constant and heat of gas production) remain constant, under ideal conditions where friction and heat losses are ignored, the instantaneous outlet flow rate of the high-pressure chamber is primarily determined by the high-pressure chamber pressure and the nozzle throat cross-sectional area. A larger throat diameter results in a larger nozzle throat cross-sectional area, and the gas flow rate discharged from the high-pressure chamber per unit time increases. Conversely, a smaller throat diameter results in a lower outlet flow rate.

[0076] After determining the nozzle size, further analysis is needed to determine the factors influencing the high-pressure chamber pressure. The temporal evolution of the high-pressure chamber pressure depends on the dynamic balance between the generation and discharge rates of high-temperature gases. On the one hand, the propellant generates high-temperature, high-pressure gases, increasing the chamber pressure; on the other hand, the high-pressure gas is discharged through the nozzle, causing the pressure to drop. The propellant's gas generation rate, the gas generation area of ​​the propellant cross section, and the gas generation rate collectively contribute to the factors influencing the high-pressure chamber pressure. Among these factors, the propellant layout plays a key role. Different propellant layouts alter the propellant's gas generation trigger location and gas propagation path, affecting the time required for the propellant cross section to be fully triggered, thereby altering the high-pressure gas generation rate curve. In other words, different propellant geometric arrangements lead to differences in the pressure rise rate and peak value within the high-pressure chamber, making them key parameters determining the high-pressure chamber pressure level.

[0077] Based on the above analysis, it can be seen that the main factors affecting the gas production device's outlet flow rate per unit time 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 layout (assuming certain propellant properties and charge). Therefore, the nozzle throat diameter and propellant layout become the core parameters determining the gas production device's exhaust performance. This theoretical calculation phase, completed before the experiment began, provided a scientific basis for the subsequent structural design and parameter selection of the gas production device, ensuring a well-reasoned experimental plan.

[0078] Gas production device assembly stage

[0079] Based on the design parameters determined by theoretical calculations, the mechanical assembly of gas generator 15 begins. The components, including the end cap, tank, nozzle, and propellant, are assembled in a predetermined sequence to form a complete gas generator. During assembly, special attention is paid to sealing (such as the installation of O-rings and gaskets) and the placement of sensors to ensure a reliable seal and a secure structure.

[0080] Detailed description:

[0081] Pre-install and seal the end cap assembly: Pre-install the plug 4 and screw plug 3 into the corresponding openings on the left side of the end cap 1 to seal the gas-producing orifice at the top of the end cap. The plug 4 is made of a plastic material to ensure reliable plugging. The plug 4 is screwed securely to the end cap using the screw plug 3. Subsequently, apply a layer of silicone rubber around the 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 before proceeding with subsequent assembly steps.

[0082] Sensor Installation: Install a pressure sensor on the sensor base 14 reserved in the upper right corner of the end cap 1. Before installation, place a ring of silicone sealing gasket on the bottom of the sensor base. Then tighten the pressure sensor to the base to ensure a secure seal at the sensor interface. This pressure sensor is used to monitor real-time pressure changes within the high-pressure chamber of the gas production unit.

[0083] Propellant Assembly: According to the designed propellant layout, several propellants 8 are assembled and fixed to a mounting plate 7. These are then secured with multiple small nuts 6 to secure the propellants securely to the mounting plate (e.g., if a ring-shaped layout is used, the propellants are 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 retaining ring 9 in the appropriate position inside tank body 2 to limit its position. Then, place the propellant assembly assembled in step 3 into tank body 2, positioning it against the retaining ring. Next, insert compression ring 5 into tank body 2 and push it over the propellant assembly to compress and secure it, preventing it from loosening or shifting within the tank.

[0085] Closing the end cap and establishing the primary seal: An O-ring 11 is placed in the O-ring groove 12 provided at the edge of the opening of the tank body 2, serving as the primary seal at the connection between the end cap and the tank body. The end cap 1 is then closed onto the tank body 2, aligning the end cap flange with the tank body flange. Multiple sets of high-strength bolt assemblies 13 are then used to securely lock the end cap 1 and tank body 2 together. Tightening the bolts requires symmetrical and even force to ensure a secure and sealed connection between the end cap and the tank body. At this point, the high-pressure chamber of the gas generator has been formed and a basic seal has been achieved.

[0086] Nozzle installation and bottom sealing: Install the nozzle 10 onto the exhaust outlet flange at the bottom of the tank body 2. During installation, first check whether there is a dedicated O-ring groove at the flange interface of the nozzle 10, and place an O-ring of appropriate size in the groove to ensure the sealing of the connection between the nozzle and the tank body. Then dock the nozzle flange with the lower flange of the tank body, and fasten the nozzle and the tank body with bolts. A high-temperature resistant polytetrafluoroethylene gasket is also inserted at the transition interface between the nozzle outlet and the external environment to further enhance the sealing and heat resistance of the nozzle interface. At this point, the assembly of the gas production device 15 is completed, forming a high-pressure gas production device with internal propellant filling, pressure sensing and sealed nozzle.

[0087] Loading into the vehicle phase

[0088] The assembled gas generator 15 is integrated and installed into the plenum chamber 16 within the vehicle 18. Bolt the gas generator to the vehicle structure, ensuring that the device outlet and the chamber inlet are securely connected. This ensures that high-temperature, high-pressure gas can flow smoothly into the plenum chamber through the nozzle and then be discharged through the exhaust port onto the vehicle surface. During this stage, the connection between the gas generator and the vehicle must be airtight to prevent leakage of high-pressure gas.

[0089] Detailed description:

[0090] Disassembly of the vehicle compartment: Select the compartment on the vehicle 18 where the gas generator 15 is installed (this compartment contains a pre-reserved plenum chamber 16 and a mounting base for the gas generator). Remove this compartment from the main body of the vehicle to expose the internal mounting flange. This compartment is typically located in the upper middle of the vehicle, near the plenum chamber area.

[0091] The gas generator is positioned and secured: The assembled gas generator 15 is moved into the vehicle compartment and positioned in alignment with the mounting flange. Multiple sets of high-strength bolt assemblies 13 are used to securely fasten the gas generator's end flange to the vehicle compartment's mounting flange, ensuring the device is securely fixed. This mounting flange directly connects to the plenum 16 within the vehicle. Once installed, the nozzle outlet of the gas generator 15 aligns with the plenum inlet.

[0092] Gas path connection and sealing: After the gas production device is fixed, the outlet of its nozzle 10 faces the inlet of the gas collecting chamber 16, and an airtight connection is achieved through a polytetrafluoroethylene gasket pre-placed between the two flanges. In this way, when the high-pressure gas production device produces gas, the high-temperature and high-pressure gas generated will be ejected through the nozzle 10 and pass through the gasket into the gas collecting chamber 16. Subsequently, the high-temperature gas is gathered in the gas collecting chamber and discharged from the navigation body through a plurality of exhaust holes 17 opened around the outer shell shoulder of the navigation body 18, and connected to the external water body. The entire gas path connection ensures a smooth path for the gas from the gas production device to the outside of the navigation body, and prevents gas leakage through components such as O-rings and gaskets, ensuring that the high-temperature gas is only discharged from the exhaust holes.

[0093] The vehicle is reassembled and restored: The vehicle section with the gas generator installed is re-docking with the rest of the vehicle. The section is reinstalled in the reverse order of disassembly, and the connecting bolts are tightened to restore the complete structure of the vehicle 18. At this point, the gas generator 15 is firmly integrated into the designated location within the vehicle, and the internal gas path (high-pressure chamber → nozzle → gas collection chamber → exhaust port) is complete, laying the foundation for the next step of setting up the experimental system.

[0094] The stage of building the vehicle experimental system

[0095] The complete vehicle 18 equipped with a gas production device is placed in a dedicated water-emergence experimental device to build a vehicle-emergence experimental system. This stage includes placing the vehicle in a cylinder 20 supported by a base 23 and installing components such as a film 21, a sealing ring 22, and a power unit 19 to simulate the environment and initial conditions of the vehicle emerging from the water. At the same time, a high-speed camera system is deployed at the experimental site to record the entire process of the vehicle emerging from the water and adjusting its attitude. After assembly at this stage, the experimental hardware system is ensured to be complete and all interfaces are well sealed, preparing for the formal experiment.

[0096] Detailed description:

[0097] Cylinder and base installation: Secure the pre-installed base 23 in the experimental pool (or tank) to the designated location, then vertically mount the transparent cylinder 20 on the base 23 and secure it securely. The base provides support for the cylinder, maintaining its vertical stability. The interior of the cylinder will serve as a guide channel for the vehicle's movement out of the water and as a container for the partial vacuum environment.

[0098] Installation of the vehicle's sealing ring: Install a sealing ring 22 where the outer surface of the vehicle 18 aligns with the inner diameter of the cylinder 20. Fit the sealing ring 22 over the corresponding diameter of the vehicle and secure it to the vehicle's outer shell with bolts. The sealing ring, made of an elastic material, forms an annular seal with the inner wall of the cylinder 20 after installation, preventing water or gas leakage from inside and outside the cylinder during the experiment and providing guidance and support for the vehicle.

[0099] Inserting the vehicle into the cylinder: Slowly lift the fully assembled vehicle 18 using a crane and lower it vertically into the opening of the cylinder 20, carefully inserting it into the cylinder. Ensure the vehicle remains centered during placement, and ensure that the sealing ring 22 maintains even contact with the inner wall of the cylinder. Once the vehicle is fully positioned, its lower portion should align or lock into the predetermined position on the base, allowing the vehicle to be suspended within the cylinder, ready to be propelled by the power unit.

[0100] Film Cover Installation: Cover the top opening of cylinder 20 with a rupturable film 21, covering and sealing the upper end. Use waterproof glue or foil tape to secure the film to the edge of the cylinder's top opening, ensuring an airtight seal. This film simulates the separation between the vehicle and the surrounding water when it emerges from the water. Once the vehicle rises and breaks through the film, the space inside the cylinder will be connected to the surrounding water, allowing the vehicle to enter the water and move. The film material should be of appropriate thickness, easily ruptured by the vehicle, and not leave large fragments that could affect its movement.

[0101] Installation of the power unit: Install the power unit 19 (such as a catapult propulsion mechanism or a compressed air drive device) at a position above the top of the cylinder 20. Usually the power unit includes a piston or spring mechanism, which can be fixed to the flange at the top of the cylinder by a high-strength bolt assembly. During installation, ensure that the power unit is aligned with the axis of the vehicle 18 and is securely connected to the cylinder so that its power can be effectively transmitted to the vehicle. The function of the power unit 19 is to give the vehicle an initial upward thrust at the beginning of the experiment, prompting the vehicle to accelerate its upward motion to complete the water exit action. After installation and fixation, perform a functional check on the power unit (such as whether the piston slides smoothly, whether the spring or air pressure is normal) to ensure that it can be triggered normally during the experiment.

[0102] Layout of the high-speed camera system: According to the experimental observation requirements, a support frame for a high-speed camera 24 is set up on the outside of the cylinder 20, and multiple high-speed cameras are installed to shoot the experimental process. The specific layout is: camera brackets are placed in front of the cylinder and on the side (for example, the left side), and one or more high-speed cameras 24 are installed at different heights on each bracket, aiming at the spatial area through which the vehicle moves out of the water. Adjust the viewing angle and focal length of each camera so that it can clearly capture the movement posture of the vehicle after entering the water and the evolution of bubbles around the vehicle when the gas production device is exhausted. The camera system is connected to the data acquisition device or the control terminal so that the video recording can be started synchronously during the experiment. After completing the layout of the camera system, check the installation status and sealing status of each part of the entire experimental system, and proceed to the next stage of the experiment after confirmation.

[0103] Experiment execution phase

[0104] After the system is built, the entire experimental system is tested for water exit. The system is lowered to a predetermined water depth and the initial conditions are adjusted (such as a negative pressure environment inside the cylinder). Then, each device is started in sequence: first, the power device propels the vehicle 18 to accelerate upward, simulating the high-speed water exit of the vehicle. During the movement, cavitation will occur on the surface of the vehicle, and then the gas production device 15 will be triggered to produce gas, which will be ventilated to the surface of the vehicle through the exhaust holes to suppress cavitation and adjust the attitude. The entire process is recorded in real time by a high-speed camera 24. The attitude adjustment effect is evaluated based on the camera results. If it does not meet expectations, the parameters such as the propellant arrangement and the nozzle size are modified in combination with the shooting data and the theoretical model, and the test is repeated until the ideal attitude control effect is obtained.

[0105] Detailed description:

[0106] Lowering and pressure adjustment: Use lifting equipment to lift the assembled water outlet test system as a whole to the target water area, and lower it to the specified water depth (for example, if simulating water outlet at a certain depth, lower it to that depth). At this time, the outside of the cylinder 20 is under a certain hydrostatic pressure. Start the vacuum pump to perform a vacuum operation on the inner cavity of the cylinder 20, so that a negative pressure environment lower than the external water pressure is formed inside the cylinder. Continue to pump air 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 of the environment during water outlet), then turn off the vacuum pump and keep the negative pressure stable for a period of time (pressure holding stage) to create the required initial conditions for the experiment.

[0107] The propulsion system is activated, and the vehicle accelerates upward: After confirming that all systems are ready, the control system issues the command to begin the experiment. First, the propulsion system 19 at the top of the cylinder is triggered according to the set program, instantly releasing energy to the vehicle 18, propelling it upward from a stationary state. The vehicle, acting under the thrust from the bottom, rises rapidly along the inner track of the cylinder 20. The acceleration and initial velocity are determined by the design parameters of the propulsion system.

[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. With the membrane ruptured, the negative pressure inside the cylinder is connected to the external water, and the vehicle officially completes its "out of the water" movement and begins to move freely in the water.

[0109] Cavitation and attitude instability: During a high-speed ascent, the surface of a vehicle experiences high-speed relative motion with the water, causing localized pressure reduction and a significant natural cavitation effect. Cavitation bubbles continuously form and grow on the surface of the vehicle, then irregularly detach and collapse, causing fluctuations in the hydrodynamic forces acting on the vehicle. This in turn causes the vehicle's motion in the water to become unstable (deflection, vibration, etc.). At this point, the vehicle's attitude becomes difficult to control autonomously and tends to deviate from its intended trajectory, necessitating timely attitude intervention.

[0110] Triggering the gas generator to exhaust: When cavitation on the vehicle's surface reaches a predetermined intensity, or when the vehicle's attitude deviates beyond a threshold (this can be determined by internal sensors detecting cavitation pressure pulsations or attitude change rates), the vehicle's control system immediately sends a start command to the gas generator 15. Upon receiving the command, the gas generator begins to produce gas, triggering the propellant 8 within it. The propellant rapidly decomposes, producing a large amount of high-temperature, high-pressure gas.

[0111] Gas is injected into and discharged from the plenum chamber: The high-temperature, high-pressure gas generated in the gas generator 15 is throttled and expanded through the nozzle 10, spraying into the plenum chamber 16 within the vehicle as a high-speed airflow. Because the air path between the gas generator and the plenum chamber is well sealed, this high-pressure airflow immediately fills the plenum chamber and is evenly ejected into the water outside the vehicle through the exhaust holes 17 around the outer shell. Within a short period of time, a large amount of gas is released near the surface of the vehicle, forming a bubble layer surrounding the vehicle's outer shape.

[0112] Cavitation Suppression and Attitude Adjustment: As the gas is expelled, the water flow field around the vehicle changes. On the one hand, the expelled gas forms an air film in 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 vehicle's surface. On the other hand, the gas ejection also exerts a certain reaction force on the vehicle, helping to correct the vehicle's attitude deviation. This combined effect significantly suppresses the cavitation effect that previously caused attitude instability, improving the balance and stability of the vehicle's movement in the water. The ventilation attitude adjustment process generally continues until the propellant gas production is completed and stops.

[0113] High-speed video monitoring and recording: Twenty-four pre-positioned high-speed cameras simultaneously captured the vehicle's motion from multiple angles throughout the entire process of ascent, cavitation generation, and gas generation and attitude adjustment. The camera system captured the entire process of the vehicle's exit from the cylinder, entry into the water, cavitation, and attitude changes after the gas generation device was deployed. After the experiment, playback of the high-speed images visually demonstrated the differences in the vehicle's attitude and surrounding cavitation distribution before and after the gas generation device was deployed, providing a detailed basis for evaluating the effectiveness of attitude control.

[0114] Result evaluation and judgment: Based on the image data recorded by the high-speed camera and the necessary measurement data (such as the pressure sensor data in the gas production device), the posture adjustment effect of this experiment is analyzed and judged:

[0115] If the cavitation phenomenon on the surface of the vehicle is significantly weakened after ventilation and exhaust, and the movement posture of the vehicle in the water tends to be stable without large swings and deflections, it means that the attitude adjustment effect of the gas-generating device is significant and the attitude adjustment experiment is successful.

[0116] If the attitude of the vehicle is still unstable after exhaust, as manifested by the fact that the influence of air on the vehicle is still strong, there are significant deviations in the movement of the vehicle or even signs of instability, it means that the ventilation attitude adjustment effect is not ideal and the expected attitude control target is not achieved.

[0117] Improvement and Repeated Testing: When experimental results do not meet expectations, the parameters of the gas production device need to be adjusted based on the observations and the test needs to be repeated. Researchers will comprehensively analyze the characteristics of the vehicle's attitude changes recorded by high-speed cameras and the results estimated by the theoretical calculation model to identify the gaps and optimize the design of the gas production device accordingly. Adjustment plans include:

[0118] Increasing the charge of the propellant 8 in the gas generating device, or changing the arrangement of the propellant (e.g., from a ring shape to a crescent shape, etc.) 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] Choose a larger nozzle diameter to increase the exhaust flow rate per unit time (release gas in larger quantities and faster, but the corresponding single exhaust duration is shortened and the exhaust pressure peak is reduced);

[0120] Select a smaller nozzle 10 throat diameter to reduce the exhaust flow rate per unit time (slow down the gas release rate, but increase the pressure in the cavity during exhaust and extend the exhaust action time).

[0121] After the adjustments were completed, the gas production device was reassembled and debugged, and the above experimental steps were repeated to conduct the water-based attitude adjustment test. Through multiple iterative tests, parameters such as the propellant layout and nozzle size were continuously optimized until the experimental results showed that the water-based attitude adjustment effect of the vehicle was achieved.

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

[0123] A method for testing a gas-generating device for adjusting the attitude of a vehicle emerging from the water. The device comprises: 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, a 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 components form the gas-generating device 15. Additionally, there are a plenum 16, an exhaust port 17, a vehicle 18, a power unit 19, a cylinder 20, a membrane 21, a sealing ring 22, a base 23, and a high-speed camera 24. First, the exhaust port outlet flow rate is estimated based on the experimental attitude adjustment requirements of the vehicle emerging from the water. According to the law of conservation of mass, the total outlet flow rate of all exhaust ports equals the inlet flow rate of the plenum and 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 gives the outlet flow rate of each exhaust port. Based on the calculated results, an appropriate propellant and nozzle are selected. According to the gas continuity equation, the gas flow rate at any section of the nozzle is equal. The nozzle throat is the critical interface, where the air flow velocity is exactly the speed of sound, that is, Ma = 1. Based on the assumption that the high-temperature and high-pressure gas flows in the nozzle throat of the high-pressure chamber in a one-dimensional, quasi-steady and isentropic manner, the high-pressure chamber outlet flow rate per unit time is The expression is:

[0124]

[0125] Considering friction and heat loss, the flow correction coefficient needs to be introduced into formula (1) but:

[0126]

[0127] In formula (2), and It is related to the performance of the propellant. Once the propellant is selected, and If they are all constants, then the outlet flow rate of the high-pressure chamber per unit time is 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 high-pressure chamber outlet flow rate per unit time. Next, we analyze the factors affecting the high-pressure chamber pressure p1.

[0128] Assume that the pressure of the high-pressure chamber when the gas production device is working is p1, the temperature is T1, the gas constant is R, and the density of the high-temperature and high-pressure gas in the high-pressure chamber when the gas production device is working is ρ1. From the ideal gas state equation, we can know:

[0129] p1=ρ1RT1 (3)

[0130] Assume that the volume of the high-pressure chamber is V1 and the mass of the propellant is mp The mass of high-temperature and high-pressure gas generated in the high-pressure chamber within time t is m b , the high pressure chamber outlet flow rate in time t is m t1 The mass of the remaining high-temperature and high-pressure gas in the high-pressure chamber is the mass of the high-temperature and high-pressure gas generated minus the mass of the high-temperature and high-pressure gas flowing out, so

[0131] ρ1V1=m b -m t1 (4)

[0132] Substituting formula (4) into formula (3), we have:

[0133]

[0134] According to the literature, the filling volume 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 derived with respect to time, and we have:

[0135]

[0136] As shown in formula (6), since the temperature is T1, the gas constant is R, and the volume of the high-pressure chamber V1 can all be approximated as constants, the factor affecting the pressure change in the high-pressure chamber is the mass of the high-temperature and high-pressure gas generated in the high-pressure chamber per unit time t. The outlet flow rate of the high-pressure chamber per unit time is First analyze The expression of is shown in formula (7):

[0137]

[0138] ρ p is the propellant density, S b is the propellant cross section, u is the gas production rate, ρ p 、S b and u are all physical property parameters of the propellant. After the propellant is selected, the three are all known constants. However, if the arrangement of the propellant is different, it will affect the triggering time of the propellant cross section. This is because when the arrangement of the propellant is different, the position of the trigger point will also change, and the distance between the trigger point and the propellant cross section will be different. The propellant gas velocity rate is a constant u1, so the time t1 when the propellant cross section is fully triggered will be different. In formula (7), S b It refers to the cross-sectional area when the propellant is fully triggered. Although S b is a constant, but at this time S bIt is not a constant but a function related to the propellant gas production rate u1 and the total triggering time t1. There is no theoretical calculation formula for this function and it can only be fitted by experimental data. Assuming S b , u1, t1 are linear functions, then:

[0139] S b =u1t1 (8)

[0140] Then, the formula (8) is continuously modified by the experimental data, and finally S b The approximate functional relationship between u1 and t1. It can be seen that the arrangement of the propellant is the one that affects is a key parameter that affects the high-pressure chamber pressure p1.

[0141] From the previous analysis, we can see that the impact The key parameters are the high pressure chamber pressure p1 and the throat area S t1 , when p1 increases, Increase, from formula (6) we can see that when increases, p1 decreases, and when p1 decreases, Decrease, and when decreases, p1 increases, and the coupling is repeated, affecting each other, making it difficult to analyze the relationship between p1 and The theoretical influence relationship can only be analyzed through experimental data to fit p1 and Therefore, the present invention simplifies the process here and does not consider As for the impact on p1, the key parameter affecting p1 is only the arrangement of the propellant.

[0142] In summary, the factors that affect the outlet flow of the high-pressure chamber 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 arrangement of the propellant, which affects the high-pressure chamber outlet flow rate per unit time. The key factor is the throat area S t1 and the arrangement of the propellants.

[0143] like Figure 1 As shown, the high pressure chamber outlet flow rate per unit time can be obtained by calculation The trend diagram of changes over time, by adjusting the layout of the propellant to achieve the high-pressure chamber outlet flow per unit time The propellant annular arrangement is as follows: Figure 1 As shown in a, the crescent-shaped arrangement of the propellant is as follows Figure 1 As shown in b, the flow rate of the high-pressure chamber outlet per unit time in the annular arrangement of the propellant The change curve is as follows Figure 1 As shown in c, the propellant crescent arrangement has the flow rate at the high pressure chamber outlet per unit time. The change curve is as follows Figure 1 d, compared Figure 1 c and Figure 1 As can be seen from d, the peak flow rate at the outlet of the annular arrangement is more prominent, but the duration of the peak period is not as long as that of the crescent arrangement. The two arrangements have their own advantages. In addition, the nozzle diameter can be adjusted to change the outlet flow rate of the high-pressure chamber per unit time. The larger the throat diameter, the The larger the value, the smaller it is. During the experiment, calculations must be performed based on the actual working conditions. 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 a set of experimental plans that better meet actual needs.

[0144] like Figure 2 As shown in the figure, the trend of the pressure p1 in the high-pressure chamber changing with time can be obtained by calculation. The pressure p1 in the high-pressure chamber can be adjusted by adjusting the arrangement of the propellant. Figure 2 a and Figure 2 As can be seen from b, the peak value of the outlet pressure p1 of the annular arrangement is more prominent, but the duration of the peak section is not as long as that of the crescent arrangement. The two arrangements have their own advantages. A pressure sensor is arranged in the high-pressure chamber. The pressure data measured by the pressure sensor can be used to correct the high-pressure chamber pressure p1 change curves of the two arrangements, thereby correcting the calculation formula of the high-pressure chamber pressure p1, making the subsequent high-pressure chamber pressure p1 calculation results closer to the experimental value, and also making the high-pressure chamber outlet flow rate It is closer to the experimental value, the whole set of calculation formulas is more accurate, and the engineering application value is higher.

[0145] The high pressure chamber outlet flow rate is obtained by calculation The trend of change of the exhaust hole can be compared with the exhaust effect of the high-speed camera to estimate the outlet flow of the high-pressure chamber. With an intuitive understanding, the underwater attitude adjustment of the navigation body can also be quantitatively analyzed to achieve more accurate adjustment targets.

[0146] like Figure 3As shown, assemble the gas production device 15 for the water exit experiment of the navigation body 18. First, install the plug 4 and the screw plug 3 to the reserved position on the left side of the end cover 1. The plug 4 is made of a material with good plasticity 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, and apply silicone rubber to the screw plug hole for sealing. This operation needs to be carried out in advance. After the silicone rubber is completely cured, subsequent operations can be carried out. Then install the pressure sensor on the sensor base 14 on the upper right side of the end cover 1. Before installation, place a ring-shaped silicone pad at the bottom of the base to ensure sealing. Then assemble several propellants 8, mounting plates 7 and small nuts 6 together, and then install the retaining ring 9, the assembly of propellant 8, mounting plate 7 and small nut 6, and the pressure ring 5 into the tank body 2, and then install the O-ring into the groove of the tank body 2, cover the end cover 1, and lock the end cover 1 and the tank body 2 with a high-strength bolt assembly 13. Finally, install the nozzle 10 under the tank body 2. There is a circle of grooves around the nozzle 10 for installing O-rings. Install the O-ring in the groove and place a polytetrafluoroethylene pad under the tank body. At this time, the gas production device 15 is assembled.

[0147] like Figure 4 As shown, the gas generating device 15 is located approximately in the middle and upper part of the inner portion of the vehicle 18, above which is the gas collecting chamber 16, and the exhaust hole 17 of the gas collecting chamber is approximately located at the shoulder of the vehicle. Figure 4 As shown, the gas generating device 15 is installed into the vehicle 18. First, the vehicle 18 compartment with the mounting flange of the gas generating device 15 is disassembled, and then the assembled gas generating device 15 is installed on the flange using high-strength bolts. The flange and the gas collecting chamber 16 in the vehicle 18 are integrated. The high-temperature and high-pressure gas generated by the gas generating device 15 can pass through the nozzle 10 through the polytetrafluoroethylene pad, and then through the mounting flange to the gas collecting chamber 16. Finally, it is discharged from the gas collecting chamber 16 to the outside along the exhaust holes 17 around the vehicle 18. After the gas generating device 15 is installed, the vehicle 18 compartment with the gas generating device 15 is combined with the other parts of the vehicle 18 to form a complete vehicle 18.

[0148] like Figure 5 As shown, the water test system of the navigation body includes a power device 19, a cylinder 20, a film 21, a sealing ring 22, a base 23, and a high-speed camera system. Figure 5 The following diagram shows the construction of a water-exit test system for a vehicle 18. First, install the cylinder 20 onto the base 23. Then, install the sealing ring 22 onto the vehicle 18 and secure it with bolts. Finally, hoist the vehicle 18 into the cylinder 20, adhere the film 21 to the top of the cylinder 20, and finally install the power unit 19 onto the cylinder 20 and secure it with a high-strength bolt assembly.

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

[0150] Finally, the water exit test of the vehicle 18 is conducted. According to the water depth requirements of the water exit test of the vehicle 18, the entire water exit test system is lowered to the target water depth, and the vacuum pump is started to draw negative pressure. When the ambient pressure drops to the experimental target pressure, the pressure is maintained. At this time, the water exit test of the vehicle 18 can be conducted. The start experiment command is issued through the external control system. First, the power device 19 starts working. Then, the vehicle 18 is pushed upward by the bottom, breaks through the top membrane 21 and enters the water. It continues to move in the water. At this time, natural cavitation will occur on the surface of the vehicle 18, making the vehicle 18 unstable and difficult to control in the water. At this time, the control system of the vehicle 18 sends a start command to the gas generating device 15. The gas generating device 15 starts to produce gas. The generated gas is discharged to the outer surface of the vehicle through the gas collecting chamber 16 and the exhaust hole 17. The gas production adjustment process can be captured by the high-speed camera 24, and the effect of the underwater motion attitude adjustment of the vehicle 18 can be judged based on this. If the natural cavitation effect after exhaust has little effect on the posture of the vehicle 18 and the vehicle 18 moves relatively steadily, it means that the posture adjustment is successful. If the natural cavitation effect still has a great influence on the posture of the vehicle 18 after exhaust, and the motion posture of the vehicle 18 is unstable, it means that the posture adjustment effect is not good, and it is necessary to adjust the amount of propellant 8 in the gas production device 15. The more propellant 8, the greater the gas production, and vice versa. Or adjust the throat diameter of the nozzle 10. The larger the throat diameter of the nozzle 10, the greater the exhaust flow rate, the smaller the exhaust pressure, and the shorter the exhaust time. Conversely, the smaller the exhaust flow rate, the greater the exhaust pressure, and the longer the exhaust time. The specific adjustment plan needs to be formulated according to the motion posture of the vehicle 18 in the water captured by the high-speed camera 24, and then the experiment is repeated.

[0151] like Figure 8 As shown, this is a workflow diagram of an experimental method of a gas-generating device 15 for adjusting the water posture of a navigation body 18 according to the present invention.

[0152] In summary, the present invention can realize the production of a large amount of high-temperature and high-pressure gas through a small-volume, high-strength, and well-sealed gas-producing device 15, and then discharge the gas to the outer surface of the navigation body 18 through the exhaust holes 17 of the gas collecting chamber 16 in the navigation body 18, thereby realizing the underwater posture adjustment of the navigation body and maintaining the stability of the underwater movement. If the adjustment effect is not good, the amount of propellant 8 in the gas-producing device 15 or the throat diameter of the nozzle 10 can be adjusted to repeat the experiment. By adjusting the amount of propellant 8 and the throat diameter of the nozzle 10, the application range of the entire navigation body 18 water test system is expanded, and the multi-working condition requirements of the underwater movement posture adjustment of the navigation body 18 can be met. The present invention has high practical engineering significance.

[0153] The above further describes the technical solution provided by the present invention in detail through several specific embodiments in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific embodiments described above are not intended to limit the present invention. Any reasonable modification and improvement of the present invention, combination of embodiments and equivalent replacement based on the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An experimental method for an air-generating device for adjusting the posture of a navigation body out of water, characterized in that: include: The steps of calculating and obtaining the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity by deriving theoretical thermal fluid dynamics and nozzle flow equations; Based on the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity, combined with the geometric arrangement model of the propellant, the law of the change of the propellant gas production area over time is deduced, and a gas production velocity model is established; The steps of predicting the cavity exhaust characteristics are as follows: calculating the pressure change process of the high-pressure cavity over time and the nozzle exhaust parameters through the gas production velocity model and gas production evolution law; The high-pressure gas cavity pressure and exhaust flow data during the actual exhaust process are collected experimentally, the experimental data are compared and analyzed with the predicted results, and the parameters of the propellant layout model and the pressure prediction model are corrected based on the difference feedback.

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

3. The experimental method of the gas generating device for adjusting the water posture of a vehicle according to claim 1, characterized in that: The temporal variation pattern of the propellant gas production area is based on the gas production starting surface and the propulsion propagation path determined by the propellant arrangement, and a linear fitting model is used to initially estimate the propellant gas production expansion process.

4. The experimental method of the gas generating device for adjusting the water posture of a vehicle according to claim 1, characterized in that: The gas production rate model presets constant parameters according to the propellant type and makes a preliminary estimate of the gas production mass per unit time in combination with the gas production expansion area.

5. The experimental method of the gas generating device for adjusting the water posture of a vehicle according to claim 1, characterized in that: The pressure change in the high-pressure gas cavity is estimated using an ideal gas state model, and a dynamic balance solution is performed based on the accumulated mass and exhaust flow rate of the high-temperature and high-pressure gas.

6. The experimental method of the gas generating device for adjusting the water posture of a vehicle according to claim 1, characterized in that: The experimental data include a high-pressure chamber pressure curve collected by a pressure sensor and an exhaust bubble evolution image sequence captured by a high-speed camera system.

7. An experimental system for a gas generating device for adjusting the posture of a navigation body out of water, characterized in that: include: A module that calculates and obtains the functional relationship between the nozzle cross-sectional area and the internal pressure of the high-pressure gas cavity by deriving theoretical thermal fluid dynamics and nozzle flow equations; 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 layout model of the propellant, the law of the change of the propellant gas production area over time is derived, and a gas production velocity model module is established; A module that calculates the time-varying process of the pressure in the high-pressure gas chamber and the exhaust parameters of the nozzle through the gas production velocity model and the gas production evolution law, and predicts the gas chamber exhaust characteristics; The module collects the high-pressure air chamber pressure and exhaust flow data during the actual exhaust process through experiments, compares and analyzes the experimental data with the predicted results, and corrects the parameters of the propellant layout model and pressure prediction model based on the difference feedback.

8. A computer storage medium for storing a computer program, characterized in that When the computer program is read by a computer, the computer executes the method according to claim 1 .

9. 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 according to claim 1 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method according to claim 1 is implemented.

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