An engine underwater test system

Abstract

This invention belongs to the field of underwater engine testing, and specifically relates to an underwater engine testing system. To test engine parameters in water depths of hundreds of meters, this invention proposes an underwater engine testing system. The system includes a test water chamber and a pressure equalization water chamber forming a communicating vessel, a control module, a water injection module, and an air injection module. The pressure equalization water chamber is equipped with a first vent valve. After engine ignition, the control module controls the opening of the first vent valve when the gas pressure in the pressure equalization water chamber exceeds the pressure corresponding to the test water depth. Utilizing the principle of communicating vessels and the incompressibility of liquids, during testing, the engine's underwater environment at depths of hundreds of meters can be simulated by controlling the injected air pressure. Simultaneously, after engine ignition, venting occurs on the pressure equalization water chamber side, ensuring relatively stable water pressure on the engine.

Description

Technical Field

[0001] This invention belongs to the field of underwater engine testing, and in particular relates to an underwater engine testing system. Background Technology

[0002] Jet engines carry their own fuel and oxidizer, operating independently of outside air. Some engines need to operate underwater, thus requiring test benches to measure their actual thrust in underwater environments. During testing, the engine needs to be subjected to specific water pressures to determine its parameters at specific water depths.

[0003] In the prior art, there exists a testing system that uses hoisting equipment to submerge an engine at a specific depth underwater for testing. Chinese invention patent CN116256178B, with an authorization announcement date of June 27, 2025, discloses an underwater engine exhaust flow field testing system. In this system, a test stand, a first watertight data chamber, a second watertight data chamber, and a camera watertight chamber are all mounted on a lifting platform. Sensor components for acquiring information needed to study the engine exhaust flow field are also mounted on the lifting platform via brackets. A first conditioning module is installed in the first watertight data chamber to process the information measured by the sensor components and transmit it to the surface monitoring and control equipment. The second watertight data chamber contains a data acquisition component and a second conditioning module that processes the information measured by the sensor components and transmits it to the acquisition component for collection and storage. A high-speed camera is installed in the camera watertight chamber to capture the morphological characteristics of the engine exhaust flow field.

[0004] During testing, the engine was first mounted on the test stand, and the lifting platform was submerged at a specific water depth using hoisting equipment. Then, the engine was ignited, and sensor components and high-speed cameras collected wake field characteristics.

[0005] In the aforementioned patent, the lifting platform needs to be submerged to a specific water depth. Since the watertight chamber can meet the pressure resistance conditions at a water depth of 200 m, the lifting platform can be submerged to a depth of more than 100 meters. At this point, the lifting platform is far from the water surface. Although there is a hoisting device to lift the lifting platform, the lifting platform and the test stand will also swing under the action of water flow or engine force, causing the engine and sensor components to swing as well, affecting the accuracy of the data collected by the sensor components and affecting the test results.

[0006] Existing technology also includes a testing system that uses a simulated water tank to test the engine. The upper end of the simulated water tank is connected to the atmosphere, the test stand is fixedly installed inside the simulated water tank, and the engine is mounted on the test stand. During testing, water is injected into the simulated water tank to a specific height, thus placing the engine at a specific water depth. The engine is then ignited, and test data is collected.

[0007] While using a simulated water tank to test an engine can prevent accidental engine shaking, the cost of building an ultra-large simulated water tank hundreds of meters high is too high. Existing simulated water tanks are generally only tens of meters high, which cannot simulate water depths of hundreds of meters, and therefore cannot measure the parameters of the engine in an environment of hundreds of meters deep.

[0008] In summary, there is an urgent need for an underwater engine testing system and method that can simulate an environment at a water depth of hundreds of meters and complete underwater engine testing. Summary of the Invention

[0009] The purpose of this invention is to provide an underwater engine testing system to solve the technical problem that existing simulated water tanks cannot simulate water depths of hundreds of meters.

[0010] To achieve the above objectives, the technical solution of the underwater engine testing system provided by this invention is as follows: An underwater engine testing system includes two sealed water chambers that form a communicating vessel. One chamber has a test bench fixedly installed inside and forms a test water chamber, while the other chamber forms a pressure equalization water chamber. The test water chamber has a door that can be opened or removed to install an engine. It also includes a control module, a water injection module for injecting water into the communicating vessel, and an air injection module for injecting air into the communicating vessel. The equalizing water chamber is equipped with a first vent valve and a first pressure sensor for detecting the air pressure inside the equalizing water chamber. The control module is communicatively connected to the first pressure sensor and the first vent valve. After the engine is ignited, the control module controls the first vent valve to open when the gas pressure inside the equalizing water chamber is greater than the pressure corresponding to the test water depth of the engine.

[0011] The beneficial effects are as follows: Utilizing the principle of communicating vessels and the incompressible property of liquids, water is injected into the communicating vessels during testing, and then air is injected into the communicating vessels after the water injection is completed, so that the engine is subjected to a specific water pressure, thereby simulating the scenario of the engine being in a specific water depth environment. By controlling the air pressure injected, the engine can be simulated to be in an underwater environment hundreds of meters deep. The operation is convenient and the cost is low.

[0012] After the engine is ignited, the high-pressure gas ejected from the engine enters the test water chamber → the air pressure in the test water chamber increases → water is squeezed into the equalizing water chamber → the air pressure in the equalizing water chamber increases → the first exhaust valve opens → the gas in the equalizing water chamber is discharged. The air pressure in the equalizing water chamber stabilizes at the air pressure corresponding to the test water depth of the engine, so that the engine can stably withstand a specific water pressure with small fluctuations in water pressure, thus enabling the engine to complete the test in a specific water depth environment scenario better.

[0013] It is important to note that in this invention, after engine ignition, venting must be performed from the equalizing water chamber, not the test water chamber. If venting is performed from the test water chamber, the pressure inside will increase explosively, and the venting process will take time. This will cause water to be forced into the equalizing water chamber, raising the water level and increasing the pressure. Consequently, due to the conduction of the liquid, the water pressure exerted on the engine will be much greater than the specified pressure, resulting in significant fluctuations in water pressure and affecting the test results.

[0014] Furthermore, the test water chamber is equipped with a second vent valve and a second pressure sensor for detecting the air pressure inside the test water chamber. The control module is communicatively connected to the second pressure sensor and the second vent valve. The control module is also used to control the opening of each vent valve when air is injected using the air injection module. The opening pressure of each vent valve is matched with the pressure corresponding to the test water depth of the engine.

[0015] The beneficial effects are as follows: by setting a second exhaust valve, if the amount of air injected is too large during air injection and pressurization, both the first and second exhaust valves will open to simultaneously exhaust air from the equalization water tank and the test water tank, so that the water level in the equalization water tank and the test water tank are always kept in the same position, which makes it easier to control the water pressure that the engine is subjected to.

[0016] Furthermore, the control module is also used to control the opening of the first and second vent valves when the water injection module is filling with water.

[0017] The beneficial effects are: during water injection, the opening of the first and second vent valves is controlled, thereby avoiding pressure buildup in the equalizing water chamber and the test water chamber, enabling water injection to be completed with a smaller injection pressure and reducing energy consumption.

[0018] Furthermore, the air injection module is only connected to the equalizing water chamber for injecting air into the equalizing water chamber.

[0019] The beneficial effects are as follows: when air is injected into the equalizing water chamber, the air pressure inside the equalizing water chamber will increase dramatically, but the flow rate of water is limited. Therefore, the increase in air pressure inside the test water chamber is relatively stable, which is helpful to determine when to stop injecting air based on the air pressure inside the test water chamber.

[0020] Furthermore, the equalizing water tank is equipped with a level gauge for displaying the water level inside the equalizing water tank.

[0021] The beneficial effect is that the water level in the equalizing water tank can be easily read through the level gauge, which facilitates the control of the water pressure at the engine.

[0022] Furthermore, the hatch is made of light-transmitting material to form an observation window, which is equipped with a high-speed camera for capturing the morphological characteristics of the engine exhaust flow field; the test bench is equipped with a sensor detection module for detecting the pressure field and temperature field generated by the engine exhaust flow field.

[0023] The beneficial effects are: the high-speed camera can record the morphological characteristics of the engine exhaust flow field, and the sensor detection module can detect the pressure field and temperature field generated by the engine exhaust flow field, which facilitates subsequent research on the engine exhaust flow field.

[0024] Furthermore, supplementary lighting was installed on the top of the test water tank.

[0025] The beneficial effect is that by using supplementary lighting, the high-speed camera can better record the morphological characteristics of the engine exhaust flow field.

[0026] Furthermore, a throttling ring is installed at the connection between the equalizing water chamber and the test water chamber.

[0027] The beneficial effect is that by limiting the flow rate of water between the two water tanks through the throttling ring, the pressure fluctuation rate in the two water tanks is limited, thereby reducing the pressure fluctuation at the engine.

[0028] Furthermore, explosion-proof valves were installed on the test water tank.

[0029] The beneficial effect is that if the pressure inside the test water tank rises abnormally after the engine is ignited, the explosion-proof valve will open to ensure test safety.

[0030] Furthermore, the equalizing water tank is equipped with a passively opened explosion-proof valve and an active explosion-proof valve that is actively opened under the control of the control module. The opening pressure of the active explosion-proof valve is lower than that of the passive explosion-proof valve.

[0031] The beneficial effect is that if the pressure in the equalizing water chamber rises abnormally after the engine is ignited, the active explosion-proof valve will be opened first. If the pressure is still uncontrollable, the passive explosion-proof valve will be opened to ensure the safety of the test. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the underwater engine testing system of the present invention; Figure 2 This is a schematic diagram of the state of an engine before ignition. Figure 3 This is a schematic diagram of the state of an engine after ignition. Figure 4 This is a schematic diagram showing the state of another engine before ignition. Figure 5 A schematic diagram of the test bench and engine after assembly; Figure 6 This is a map showing the location distribution of some measuring points; Figure 7 This is a map showing the location distribution of another set of measuring points.

[0033] Explanation of reference numerals in the attached figures: 1. First passive explosion-proof valve; 2. Second exhaust valve; 3. Water injection pipeline; 4. First standby exhaust valve; 5. Control panel; 6. Water injection pump; 7. Second passive explosion-proof valve; 8. First exhaust valve; 9. Active explosion-proof valve; 10. Second standby exhaust valve; 11. Air injection pipeline; 12. Shut-off valve; 13. Air compressor; 14. Cooling pump; 15. Inspection window; 16. First drain pipeline; 17. Equalizing water tank; 18. Level gauge; 19. Connecting pipe; 20. Throttling ring; 21. Engine; 22. Test bench; 23. Second drain pipeline; 24. Ignition and test line mounting flange; 25. Observation window; 26. 27. Engine control console; 28. Test water tank; 29. ​​Backup exhaust port; 30. Backup air compressor interface; 31. Supplemental light; 322. Measuring point mounting position; 323. First measuring point; 324. Second measuring point; 325. Third measuring point; 326. Fourth measuring point; 327. Fifth measuring point; 328. Sixth measuring point; 329. Seventh measuring point; 320. Eighth measuring point; 321. Ninth measuring point; 322. Tenth measuring point; 100. First initial water level; 200. Second initial water level; 300. First final water level; 400. Second final water level; 500. Third initial water level; 600. Fourth initial water level. Detailed Implementation

[0034] To address the problems in the background art, the core inventive concept of this invention is as follows: utilizing the principle of communicating vessels and the incompressible property of liquids, the engine located inside the communicating vessel is subjected to a specific water pressure by controlling the air pressure inside the communicating vessel, thereby simulating the scenario of the engine being in a specific water depth environment; after the engine is ignited, the pressure equalization water tank of the engine is not vented to ensure that the water pressure on the engine is relatively stable, thereby better completing the test of the engine being in a specific water depth environment scenario.

[0035] The present invention will be further described in detail below with reference to the embodiments.

[0036] Embodiments of the underwater engine testing system provided by this invention: like Figure 1 As shown, the underwater engine testing system includes two sealed water tanks that form a communicating vessel. One of them is fixedly installed with the test stand 22 by welding or bolting and forms the test water tank 27. The other forms the equalizing water tank 17. The test water tank 27 has a hatch that can be opened or removed to install the engine 21. The underwater engine testing system also includes a control module, a water injection module for injecting water into the communicating vessel, and an air injection module for injecting air into the communicating vessel. The equalizing water chamber 17 is equipped with a first vent valve 8 and a first pressure sensor for detecting the air pressure inside the equalizing water chamber 17. The control module is communicatively connected to the first pressure sensor and the first vent valve 8. After the engine 21 is ignited, the control module controls the first vent valve 8 to open when the gas pressure inside the equalizing water chamber 17 is greater than the pressure corresponding to the test water depth of the engine 21. The first vent valve 8 is used to stabilize the water pressure on the engine 21, and is therefore also called a pressure stabilizing device or pressure stabilizing valve. The opening pressure of the first vent valve 8 is determined by the depth to be simulated. If the depth to be simulated is H, and the height difference between the corresponding height of the engine 21 and the water surface inside the equalizing water chamber 17 is l, then the opening pressure of the first vent valve 8 is ρg(Hl), where ρ is the density of water and g is the gravitational constant.

[0037] The control module is located at the central control console 5. The control module includes a CPU and other control chips, and can specifically be an engineering computer or similar equipment. In this invention, communication connections between electrical devices can be achieved via wired methods such as wires or optical fibers, or via wireless methods such as WiFi, 2.4G networks, Bluetooth, or 5G networks.

[0038] The lower parts of the equalizing water chamber 17 and the sealed water chamber are connected by a connecting pipe 19 to form a communicating vessel. The connecting pipe 19 can be a flexible metal hose. Preferably, the connecting pipe 19 is equipped with a throttling ring 20 to limit the speed at which water transfers between the two water chambers, ensuring smooth pressure changes in each chamber. The bottom of the equalizing water chamber 17 and the test water chamber 27 are respectively equipped with a first drain pipe 16 and a second drain pipe 23 to drain water after the test is completed. The test water chamber 27 is equipped with an ignition and test line mounting flange 24 so that the watertight cable connected to the engine control console 26 can enter the test water chamber 27 through the flange and be electrically connected to the engine, while preventing water leakage from the test water chamber 27.

[0039] The water injection module includes a water injection pump 6 and a water injection pipeline 3 connecting the water injection pump 6 and the connecting device. The water injection pipeline 3 and / or the connecting device are equipped with valves for closing the water injection pipeline 3 to prevent gas backflow to the water injection pump 6. The water injection pipeline 3 may be connected only to the test water chamber 27, only to the equalizing water chamber 17, or simultaneously to both the test water chamber 27 and the equalizing water chamber 17.

[0040] The air injection module includes a high-pressure air source and an air injection pipeline 11 connecting the high-pressure air source and the connector. At least one of the air injection pipeline 11, the high-pressure air source, and the connector is equipped with a shut-off valve 12 for closing the air injection pipeline 11 to prevent gas from flowing back into the high-pressure air source after the engine 21 is ignited. Figure 1 In the middle section, the high-pressure air source is air compressor 13, which is equipped with a cooling system. Figure 1 The cooling pump 14 of the cooling system is shown in the figure.

[0041] In one embodiment, the air injection module is only connected to the equalizing water chamber 17 for injecting air into the equalizing water chamber 17. When air is injected into the equalizing water chamber 17, the air pressure inside the equalizing water chamber 17 will increase sharply, but the flow rate of water is limited, so the increase in air pressure inside the test water chamber 27 is relatively stable. A second pressure sensor can be installed inside the test water chamber 27 to detect the air pressure inside the test water chamber 27. The second pressure sensor is communicatively connected to the control module so that it can roughly determine when to slow down the air injection rate and stop the air injection based on the air pressure inside the test water chamber 27, so as to avoid a large amount of gas being discharged through the first exhaust valve 8 during air injection and reduce energy consumption.

[0042] In other embodiments, the gas injection module may be connected only to the test water chamber 27 or simultaneously to both the test water chamber 27 and the equalizing water chamber 17, in which case the gas injection and pressurization operation can still be completed. Figure 1 In the test water tank 27, a spare air compressor interface 29 is provided, which can be used to connect to the air injection line 11.

[0043] This invention utilizes the principle of communicating vessels and the incompressible property of liquids. During testing, water is injected into the communicating vessels through a water injection module. After the water injection is completed, air is injected into the communicating vessels through an air injection module to pressurize them, so that the engine 21 can withstand a specific water pressure, thereby simulating the scenario where the engine 21 is in a specific water depth environment. By controlling the air pressure, the engine 21 can be simulated to be in an underwater environment hundreds of meters deep. It is easy to operate and has low cost.

[0044] like Figure 2 As shown, before engine 21 ignites, the water level in test water tank 27 is the first initial water level of 100, and the water level in equalizing water tank 17 is the second initial water level of 200. Figure 2 and Figure 3 As shown, after engine 21 is ignited, the high-pressure gas ejected by engine 21 enters the test water chamber 27 → the air pressure in the test water chamber 27 increases → water is squeezed into the equalizing water chamber 17, the water level in the test water chamber 27 decreases to the first final water level 300, the water level in the equalizing water chamber 17 increases to the second final water level 400 → the air pressure in the equalizing water chamber 17 increases → the first exhaust valve 8 opens → the gas in the equalizing water chamber 17 is discharged, and the air pressure in the equalizing water chamber 17 stabilizes at the air pressure corresponding to the test water depth of engine 21, so that engine 21 can stably withstand a specific water pressure, the water pressure fluctuation of engine 21 is small, and thus the test of engine 21 in a specific water depth environment scenario can be completed well.

[0045] It should be specifically noted that, in this invention, as Figure 2 and Figure 3 As shown, if the height difference between the second final water level 400 and the second initial water level 200 is defined as h, Figure 2The water pressure on engine 21 at the indicated moment is P1. Figure 3 At the indicated moment, the water pressure on engine 21 is P2, then P2 - P1 = ρgh, where ρ is the density of water and g is the gravitational constant. Although the water pressure on engine 21 fluctuates by ρgh, since the height of each water tank is generally only a few meters or tens of meters, the value of h is generally only about 1 meter, while the simulated water depth of engine 21 is generally several hundred meters, the fluctuation in water pressure on engine 21 is only a few hundredths of a percent, which does not affect the accuracy of the test results. Therefore, it is not necessary to compensate for the pressure change caused by the rise in the liquid level in the equalizing water tank 17, making the control logic simpler and easier to implement.

[0046] Of course, the pressure change caused by the rise in the liquid level in the equalizing water tank 17 can also be compensated. In this case, a liquid level sensor connected to the control module needs to be installed in the equalizing water tank 17 or the test water tank 27 to detect the increase in the water level in the equalizing water tank 17 or the decrease in the water level in the test water tank 27, so as to determine the change in the water level height Δh in the equalizing water tank 17 after the engine 21 is ignited. If the air pressure in the equalizing water tank 17 before the engine 21 is ignited is defined as P3, then the control module needs to control the opening pressure corresponding to the first exhaust valve 8 to be adjusted to P3-ρgΔh.

[0047] Furthermore, in this invention, after engine 21 is ignited, exhaust must be vented from the equalizing water chamber 17, not from the test water chamber 27. If exhaust is vented from the test water chamber 27, the air pressure inside the test water chamber 27 will increase explosively, and the exhaust will take time. This will cause water to be forced into the equalizing water chamber 17, raising the water level inside the equalizing water chamber 17 and increasing the air pressure inside the equalizing water chamber 17. Therefore, due to the conduction of the liquid, the water pressure on engine 21 will be much greater than the specified water pressure, resulting in large fluctuations in the water pressure on engine 21 and affecting the test results.

[0048] like Figure 1 As shown, based on Example 1, the test water tank 27 is also equipped with a second exhaust valve 2 and a second pressure sensor for detecting the air pressure inside the test water tank 27. The control module is communicatively connected to the second pressure sensor and the second exhaust valve 2. The control module is also used to control the opening of each exhaust valve when the air injection module is used to inject air. The opening pressure of each exhaust valve is matched with the pressure of the engine 21 corresponding to the test water depth.

[0049] By setting a second vent valve 2, if the amount of air injected is too large during pressurization, both the first vent valve 8 and the second vent valve 2 will open to simultaneously vent air from the equalizing water tank 17 and the test water tank 27. This ensures that the water level in the equalizing water tank 17 and the test water tank 27 remains consistent, achieving [the desired effect]. Figure 2 The state shown facilitates the control of the water pressure exerted on the engine 21. Figure 2 In this test chamber, the pressure equalization chamber 17 and the test chamber 27 have the same air pressure. Therefore, when injecting air, if only the pressure equalization chamber 17 is injected, it is easy to determine whether to stop the injection by the air pressure in the test chamber 27.

[0050] In other embodiments, the second exhaust valve 2 may not be provided. In this case, such as Figure 4 As shown, after air is injected into the equalizing water chamber 17, the third initial water level 500 in the test water chamber 27 is higher than the fourth initial water level 600 in the equalizing water chamber 17.

[0051] In an embodiment where a first vent valve 8 and a second vent valve 2 are provided simultaneously, preferably, the control module is also used to control the opening of the first vent valve 8 and the second vent valve 2 when the water injection module is injecting water, thereby avoiding pressure buildup in the equalizing water chamber 17 and the test water chamber 27, enabling water injection to be completed with a smaller injection pressure and reducing energy consumption.

[0052] Preferably, in one embodiment, the equalizing water tank 17 is equipped with a level gauge 18 for displaying the water level inside the equalizing water tank 17, so as to facilitate reading the water level inside the equalizing water tank 17 and to facilitate control of the water pressure at the engine 21. At the same time, it can also be conveniently determined whether the water level has exceeded 50 times the nozzle diameter of the engine 21 during water filling, ensuring that the engine 21 is completely underwater.

[0053] In addition to the ability to measure the thrust of engine 21 on test stand 22, the present invention also makes the following improvements in order to study the exhaust flow field of engine 21.

[0054] like Figure 1 As shown, the hatch is made of light-transmitting material to form an observation window 25. Of course, an observation window 25 can also be installed on the hatch. A high-speed camera for photographing the morphological characteristics of the exhaust flow field of the engine 21 is set at the observation window 25. To facilitate photography, a supplementary light 30 is also installed in the test water tank 27. The test stand 22 is equipped with a sensor detection module for detecting the pressure field and temperature field generated by the exhaust flow field of the engine 21.

[0055] like Figures 5-7 As shown, an arc-shaped plate is provided on the test bench 22 at the position corresponding to the nozzle of the engine 21. An axial plate extending along the axial direction of the engine 21 is fixedly connected to the arc-shaped plate. Threaded holes are provided on the arc-shaped plate and the axial plate. The engine 21 also has threaded holes to install the sensor detection module at the threaded holes. The threaded holes constitute the measuring point mounting position 31.

[0056] like Figure 6 and Figure 7As shown, four measuring points are set radially on the engine 21: measuring point 321, measuring point 322, measuring point 323, and measuring point 324. Three actual measuring points and one dummy measuring point are set axially on the engine 21: the five actual measuring points are measuring point 325, measuring point 326, and measuring point 327; the dummy measuring point is the center point of the line connecting measuring points 323 and 324. Three actual measuring points and one dummy measuring point are set circumferentially on the engine 21: the eight actual measuring points are measuring point 328, measuring point 329, and measuring point 3210; the dummy measuring point is the center point of the line connecting measuring points 323 and 324. A sensor detection module is installed at each measuring point.

[0057] In this invention, to ensure experimental safety, a first passive explosion-proof valve 1 is installed on the test water chamber 27, and a second passive explosion-proof valve 7 is installed on the equalizing water chamber 17 to prevent safety accidents when the pressure inside the water chamber rises abnormally. Since a large amount of gas needs to be discharged from the equalizing water chamber 17, an active explosion-proof valve 9, which is communicatively connected to the control module, is also installed inside the equalizing water chamber. When the pressure inside the equalizing water chamber 17 rises abnormally, the active explosion-proof valve 9 can be opened to release pressure. The opening pressure of the active explosion-proof valve 9 is lower than the opening pressure of the second passive explosion-proof valve 7. If the pressure inside the equalizing water chamber 17 still rises abnormally after only opening the active explosion-proof valve 9, then the second passive explosion-proof valve 7 will open.

[0058] In this invention, following the principle of one valve in use and one in reserve, a first backup exhaust valve 4 corresponding to the first exhaust valve 8 and a second backup exhaust valve 10 corresponding to the second exhaust valve 2 are also provided. Under normal circumstances, the backup exhaust valves are not in operation. The backup exhaust valves can be activated if the corresponding exhaust valve fails. When the pressure inside the water tank rises abnormally, both the exhaust valve and the corresponding backup exhaust valve can be opened simultaneously to avoid safety accidents. A backup exhaust port 28 is also provided on the test water tank 27.

[0059] For ease of maintenance, the equalizing water chamber 17 is equipped with an inspection window 15, and the hatch or observation window 25 on the test water chamber 27 constitutes an inspection door or inspection window.

[0060] It should be noted that there is a nozzle plug at the nozzle of engine 21 to prevent water from flowing back into the combustion chamber of engine 21 before engine 21 is ignited.

[0061] The following describes an underwater engine testing method using the underwater engine testing system of the present invention.

[0062] Test method 1.

[0063] Before testing, the hatch needs to be opened and the engine 21 installed on the test stand 22. If it is necessary to study the exhaust flow field of the engine 21, a watertight sensor detection module also needs to be installed. Afterward, the hatch is closed and a height camera is installed at the observation window 25. When the hatch is composed of the observation window 25, opening the hatch means removing the observation window 25, and closing the hatch means installing the observation window 25 on the body of the test water tank 27. The observation window 25 can be connected to the body flange.

[0064] During testing, perform the following steps: Step S1: Use the water injection module to inject water into the communicating vessel to the set water level; Step S2: Use the air injection module to inject air into the communicating vessel until the gas pressure in each water tank matches the pressure corresponding to the test water depth of engine 21. Step S3: Control the engine 21 to ignite. When the gas pressure in the equalizing water chamber 17 is greater than the pressure corresponding to the test water depth of the engine 21, control the first exhaust valve 8 to open. If the required simulated depth is H, and the height difference between the height of the engine 21 and the water surface in the equalizing water chamber 17 is l, then the opening pressure of the first exhaust valve 8 is ρg(Hl), where ρ is the density of water and g is the gravitational constant.

[0065] This invention utilizes the principle of communicating vessels and the incompressible property of liquids. During testing, water is injected into the communicating vessels via a water injection module. After water injection, air is injected into the communicating vessels via an air injection module to pressurize them, causing the engine 21 to withstand a specific water pressure. This simulates a scenario where the engine 21 is in a specific water depth environment. By controlling the air pressure, the underwater environment of the engine 21 at a depth of hundreds of meters can be simulated. The operation is convenient and cost-effective. Simultaneously, the engine 21 is fixed by the test stand 22 and the test water tank 27, which can prevent abnormal shaking of the engine 21 and improve the accuracy of the test results.

[0066] like Figure 2 As shown, before engine 21 ignites, the water level in test water tank 27 is the first initial water level of 100, and the water level in equalizing water tank 17 is the second initial water level of 200. Figure 2 and Figure 3As shown, after engine 21 is ignited, the high-pressure gas ejected by engine 21 enters the test water chamber 27 → the air pressure in the test water chamber 27 increases → water is squeezed into the equalizing water chamber 17, the water level in the test water chamber 27 decreases to the first final water level 300, the water level in the equalizing water chamber 17 increases to the second final water level 400 → the air pressure in the equalizing water chamber 17 increases → the first exhaust valve 8 opens → the gas in the equalizing water chamber 17 is discharged, and the air pressure in the equalizing water chamber 17 stabilizes at the air pressure corresponding to the test water depth of engine 21, so that engine 21 can stably withstand a specific water pressure, the water pressure fluctuation of engine 21 is small, and thus the test of engine 21 in a specific water depth environment scenario can be completed well.

[0067] It should be specifically noted that, in this invention, as Figure 2 and Figure 3 As shown, if the height difference between the second final water level 400 and the second initial water level 200 is defined as h, Figure 2 The water pressure on engine 21 at the indicated moment is P1. Figure 3 At the indicated moment, the water pressure on engine 21 is P2, then P2 - P1 = ρgh, where ρ is the density of water and g is the gravitational constant. Although the water pressure on engine 21 fluctuates by ρgh, since the height of each water tank is generally only a few meters or tens of meters, the value of h is generally only about 1 meter, while the simulated water depth of engine 21 is generally several hundred meters, the fluctuation in water pressure on engine 21 is only a few hundredths of a percent, which does not affect the accuracy of the test results. Therefore, it is not necessary to compensate for the pressure change caused by the rise in the liquid level in the equalizing water tank 17, making the control logic simpler and easier to implement.

[0068] Of course, the pressure change caused by the rise in the liquid level in the equalizing water tank 17 can also be compensated. In this case, a liquid level sensor connected to the control module needs to be installed in the equalizing water tank 17 or the test water tank 27 to detect the increase in the water level in the equalizing water tank 17 or the decrease in the water level in the test water tank 27, so as to determine the change in the water level height Δh in the equalizing water tank 17 after the engine 21 is ignited. If the air pressure in the equalizing water tank 17 before the engine 21 is ignited is defined as P3, then the control module needs to control the opening pressure corresponding to the first exhaust valve 8 to be adjusted to P3-ρgΔh.

[0069] Furthermore, in this invention, after engine 21 is ignited, exhaust must be vented from the equalizing water chamber 17, not from the test water chamber 27. If exhaust is vented from the test water chamber 27, the air pressure inside the test water chamber 27 will increase explosively, and the exhaust will take time. This will cause water to be forced into the equalizing water chamber 17, raising the water level inside the equalizing water chamber 17 and increasing the air pressure inside the equalizing water chamber 17. Therefore, due to the conduction of the liquid, the water pressure on engine 21 will be much greater than the specified water pressure, resulting in large fluctuations in the water pressure on engine 21 and affecting the test results.

[0070] Test method 2.

[0071] During testing, perform the following steps: Step S1: Use the water injection module to inject water into the communicating vessel to the set water level; Step S2: Use the air injection module to inject air into the communicating vessel. When the gas pressure in each water tank is greater than the pressure corresponding to the test water depth of engine 21, control the corresponding exhaust valve to open until the gas pressure in each water tank matches the pressure corresponding to the test water depth of engine 21. Step S3: Control the engine 21 to ignite, and control the first exhaust valve 8 to open when the gas pressure in the equalizing water chamber 17 is greater than the pressure corresponding to the test water depth of the engine 21.

[0072] Compared to Example 1, in Example 2, if the air injection volume is too large in step S2, both the first vent valve 8 and the second vent valve 2 are opened to simultaneously vent air from the equalizing water chamber 17 and the test water chamber 27, thereby ensuring that the water level in the equalizing water chamber 17 and the test water chamber 27 remains consistent, achieving... Figure 2 The state shown facilitates the control of the water pressure exerted on the engine 21. Figure 2 In this test chamber, the pressure equalization chamber 17 and the test chamber 27 have the same air pressure. Therefore, when injecting air, if only the pressure equalization chamber 17 is injected, it is easy to determine whether to stop the injection by the air pressure in the test chamber 27.

[0073] Preferably, in step S1, the first vent valve 8 and the second vent valve 2 are opened to avoid pressure buildup in the equalizing water chamber 17 and the test water chamber 27, so that water injection can be completed with a smaller injection pressure and energy consumption can be reduced.

[0074] Preferably, in step S2, air is injected only into the equalizing water chamber 17. When air is injected into the equalizing water chamber 17, the air pressure inside the equalizing water chamber 17 will increase sharply, but the flow rate of water is limited. Therefore, the increase in air pressure inside the test water chamber 27 is relatively stable, which is beneficial for determining when to stop injecting air based on the air pressure inside the test water chamber 27.

[0075] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features, or organically combine different embodiments to create the embodiments shown in the accompanying drawings. Of course, those skilled in the art can also create other embodiments not shown in the accompanying drawings. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An underwater engine testing system, characterized in that, It includes two closed water tanks that form a communicating vessel, one of which has a test stand fixedly installed inside and forms a test water tank, and the other forms a pressure equalization water tank. The test water tank has a hatch that can be opened or removed to install the engine. It also includes a control module, a water injection module for injecting water into the communicating vessel, and an air injection module for injecting air into the communicating vessel. The equalizing water chamber is equipped with a first vent valve and a first pressure sensor for detecting the air pressure inside the equalizing water chamber. The control module is communicatively connected to the first pressure sensor and the first vent valve. After the engine is ignited, the control module controls the first vent valve to open when the gas pressure inside the equalizing water chamber is greater than the pressure corresponding to the test water depth of the engine.

2. The underwater engine testing system as described in claim 1, characterized in that, The test water chamber is equipped with a second vent valve and a second pressure sensor for detecting the air pressure inside the test water chamber. The control module is communicatively connected to the second pressure sensor and the second vent valve. The control module is also used to control the opening of each vent valve when air is injected using the air injection module. The opening pressure of each vent valve is matched with the pressure corresponding to the test water depth of the engine.

3. The underwater engine testing system as described in claim 2, characterized in that, The control module is also used to control the opening of the first and second vent valves when the water injection module is filling with water.

4. The underwater engine testing system as described in claim 2, characterized in that, The air injection module is only connected to the equalizing water chamber for injecting air into the equalizing water chamber.

5. The underwater engine testing system as described in any one of claims 1 to 4, characterized in that, The equalizing water tank is equipped with a level gauge to display the water level inside the equalizing water tank.

6. The underwater engine testing system as described in any one of claims 1 to 4, characterized in that, The hatch is made of light-transmitting material to form an observation window, which is equipped with a high-speed camera for capturing the morphological characteristics of the engine exhaust flow field; the test bench is equipped with a sensor detection module for detecting the pressure field and temperature field generated by the engine exhaust flow field.

7. The underwater engine testing system as described in claim 6, characterized in that, The test water tank is equipped with supplemental lighting on its top.

8. The underwater engine testing system as described in any one of claims 1 to 4, characterized in that, A throttling ring is installed at the connection between the equalizing water chamber and the test water chamber.

9. The underwater engine testing system as described in any one of claims 1 to 4, characterized in that, The test water tank is equipped with an explosion-proof valve.

10. The underwater engine testing system as described in any one of claims 1 to 4, characterized in that, The equalizing water tank is equipped with a passively opened explosion-proof valve and an active explosion-proof valve that is actively opened under the control of the control module. The opening pressure of the active explosion-proof valve is lower than that of the passive explosion-proof valve.

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