Water ramjet nozzle atomization characteristic test device and test method

Abstract

The invention discloses a water ramjet nozzle atomization characteristic test device which comprises a frame and a high-pressure liquid supply system integrated on the frame, and a high-pressure gas tank, a high-pressure liquid tank and a liquid output main pipeline are sequentially connected through pipelines. The high-pressure gas tank acts on the high-pressure liquid tank to pressurize liquid stored in the high-pressure liquid tank. And the atomization observation box is made of a transparent material, so that a visual space is provided for the formation of a spray field. The tail end of the liquid output main pipeline is provided with a connecting part, different types of nozzles to be tested can be rapidly installed and replaced, and the nozzles can be accurately positioned at the optimal test position in the observation box. The schlieren instrument, the high-speed camera and the laser particle analyzer form a multi-dimensional non-contact measurement network from a macroscopic flow field to a microscopic particle size. A flow speed control system composed of a flow meter and an electric control regulating valve provides a basis for accurately controlling the stability of liquid supply. The invention further discloses a test method for carrying out the atomization test on the nozzle of the water ramjet engine by adopting the test device.

Description

Technical Field

[0001] This application relates to the field of engine testing equipment technology, and in particular to a test device and test method for the atomization characteristics of a water jet engine nozzle. Background Technology

[0002] As a core component of a water-ramjet engine, the nozzle's function is to atomize liquid working fluids such as water to facilitate efficient combustion with metallic fuels. The quality of atomization directly determines combustion efficiency, stability, and engine thrust. Therefore, during the research and development process, it is necessary to accurately measure the nozzle's atomization characteristics, such as the spray cone angle and droplet velocity distribution.

[0003] Currently, most mainstream nozzle atomization testing devices adopt mature solutions from the aviation fuel engine field. However, when these devices are directly applied to the testing of water ramjet engine nozzles, they have significant shortcomings: First, their air supply unit directly provides atomizing air to the nozzle instead of creating a high-pressure environment for the liquid working fluid, which cannot simulate the actual high-pressure conditions of the water ramjet engine combustion chamber, resulting in distorted test data; second, their observation chamber design focuses on fuel recovery and environmental protection, without considering the closed back pressure environment of simulating the combustion chamber, and also lacks a dedicated layout for simultaneous and efficient measurement of multiple optical devices; third, their functional design is for single-point fuel injection, making it difficult to conveniently extend to the testing needs of special nozzles such as gas-liquid two-phase flow nozzles.

[0004] Therefore, existing technologies lack a dedicated water jet engine nozzle testing device that can realistically simulate high-pressure operating conditions, integrate and optimize the observation system, and has good scalability. Summary of the Invention

[0005] This application provides a testing device and method for testing the atomization characteristics of a water-jet engine nozzle, aiming to solve the problems of existing technologies that cannot simulate the real working conditions of water-jet engine nozzles, have low measurement efficiency, and limited functionality. The technical solution is as follows:

[0006] In a first aspect, a water-jet engine nozzle atomization characteristic testing device includes: a frame; a high-pressure liquid supply system integrated on the frame, comprising a high-pressure gas tank, a high-pressure liquid tank, and a liquid output main pipeline connected sequentially by pipelines, wherein the high-pressure gas tank is used to pressurize the liquid in the high-pressure liquid tank; an atomization observation chamber, a closed cavity made of transparent material, disposed on the frame, having an openable and closable sealed top cover and a venting interface on the side wall or bottom; a back pressure regulating system connected to the venting interface for regulating and maintaining the pressure inside the atomization observation chamber; a connecting part at the end of the liquid output main pipeline for detachably installing the nozzle to be tested and positioning the nozzle outlet at a test position inside the atomization observation chamber; an optical measurement system including a schlieren meter, a high-speed camera, and a laser particle size analyzer disposed on the outer periphery of the atomization observation chamber; and a flow rate control system including a flow meter and an electronically controlled regulating valve disposed on the liquid output main pipeline.

[0007] Optionally, the laser particle size analyzer includes a laser emitter and a laser receiver, which are respectively disposed on the opposite side walls of the atomization observation box and at the same horizontal height, and the direction of their connection is orthogonal to the central axis of the nozzle installed on the connecting part; the schlieren and the high-speed camera are arranged around the atomization observation box, and their optical paths and shooting angles do not interfere with each other.

[0008] Optionally, the inner wall of the fogging observation box is covered with a hydrophobic film; and / or, the outer wall of the fogging observation box is provided with a diffuser for providing backlight for the high-speed camera.

[0009] Optionally, the flow rate control system further includes a controller; the flow meter, the electrically controlled regulating valve, and the pressure sensor and temperature sensor installed on the high-pressure liquid tank are all connected to the controller; the controller is used to adjust the opening of the electrically controlled regulating valve according to the feedback signal of the flow meter to control the flow rate, and to simultaneously monitor and record pressure and temperature parameters.

[0010] Optionally, the device further includes a spare branch gas pipe, the outlet of which is guided to the vicinity of the connection portion to provide auxiliary gas for the gas-liquid two-phase flow nozzle installed on the connection portion.

[0011] Optionally, the frame is equipped with casters with locking function at the bottom.

[0012] Secondly, a method for testing the atomization characteristics of a water-jet engine nozzle using the aforementioned testing apparatus includes the following steps:

[0013] S1: Install the nozzle to be tested to the connection part and position it at the test position inside the atomization observation box, then close the sealing cover;

[0014] S2: Activate the back pressure regulation system to adjust and stabilize the internal pressure of the atomization observation box to the set simulated working condition pressure;

[0015] S3: The flow rate control system controls the high-pressure gas tank to pressurize the liquid in the high-pressure liquid tank and adjusts and stabilizes the liquid flow rate to the set value;

[0016] S4: High-pressure liquid is supplied to the nozzle under test to form a spray field, and the optical measurement system is triggered to perform synchronous data acquisition at the same time.

[0017] S5: The data collected by the optical measurement system includes: macroscopic density field image of the spray obtained by the schlieren, transient morphology image of the spray obtained by the high-speed camera, and droplet size distribution data obtained by the laser particle size analyzer.

[0018] Optionally, in step S4, when the nozzle to be tested is a gas-liquid two-phase flow nozzle, auxiliary gas with set parameters is also provided to the nozzle through the backup branch gas pipe.

[0019] Optionally, in step S3, the controller synchronously records the liquid flow rate, the pressure and temperature inside the high-pressure liquid tank, and the pressure data inside the atomization observation box, and adds corresponding timestamps and operating condition tags to the data frames collected by the optical measurement system.

[0020] Optionally, in step S2, the back pressure regulation system maintains the internal pressure of the atomization observation box at a set value that is higher or lower than the ambient atmospheric pressure.

[0021] The beneficial effects of the technical solutions provided in this application include at least the following:

[0022] The water-jet engine nozzle atomization characteristic testing device includes a frame serving as a support base, with a high-pressure liquid supply system integrated on the frame. A high-pressure gas tank, a high-pressure liquid tank, and a liquid output main pipeline are sequentially connected via pipelines. The high-pressure gas tank pressurizes the liquid stored in the high-pressure liquid tank. An atomization observation box, constructed of transparent material and mounted on the frame, provides a visualization space for the formation and development of the spray field. A connection point at the end of the liquid output main pipeline allows for the quick installation and replacement of different types of nozzles under test, and precise positioning of the nozzles in the optimal testing location within the observation box. An optical measurement system surrounding the atomization observation box integrates a schlieren spectrometer, a high-speed camera, and a laser particle size analyzer, forming a multi-dimensional, non-contact measurement network from macroscopic flow fields to microscopic particle sizes. Furthermore, a flow rate control system composed of a flow meter and an electronically controlled regulating valve provides a foundation for precisely controlling the stability of the liquid supply. This application's embodiment provides a fully functional and highly accurate dedicated hardware platform for testing water-jet engine nozzles. This device integrates high-pressure simulation, observation, and measurement and control, fundamentally solving the measurement distortion problem caused by operating condition mismatch in traditional devices. This lays a solid physical foundation for obtaining atomization data with high engineering guidance value. Simultaneously, the experimental method provided in this application organically coordinates the various subsystems of the aforementioned device, establishing a complete and efficient testing process from precise operating condition simulation to synchronous data acquisition and automatic result correlation. This method not only ensures high repeatability of each test condition and high reliability of the data, but more importantly, it makes it possible to efficiently and systematically acquire a comprehensive atomization characteristic database of water-rammed engine nozzles under realistic simulated operating conditions in the laboratory. This significantly shortens the research and development cycle and provides direct and powerful experimental evidence for nozzle optimization design and engine performance prediction.

[0023] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional schematic diagram of the water jet engine nozzle atomization characteristic test device provided in the embodiments of this application;

[0026] Figure 2 This is a three-dimensional schematic diagram of the water jet engine nozzle atomization characteristic test device provided in the embodiment of this application without the frame;

[0027] Figure 3 This is a front cross-sectional view of the water jet engine nozzle atomization characteristic test device provided in the embodiments of this application;

[0028] Figure 4 This is a partial cross-sectional view of the atomization observation box section when testing a gas-liquid two-phase flow nozzle using the water-jet engine nozzle atomization characteristic test device provided in the embodiments of this application.

[0029] Explanation of reference numerals in the attached figures

[0030] 1-Frame; 2-Atomization observation box; 201-Sealed top cover; 202-Ventilation interface; 3-Controller; 4-High-pressure gas tank; 401-Branch gas pipe; 5-High-pressure liquid tank; 501-Pressure sensor; 502-Temperature sensor; 6-Nozzle; 7-Schizophonometer; 8-High-speed camera; 9-Laser particle size analyzer; 901-Laser emitter; 902-Laser receiver; 10-Flow meter; 11-Electrically controlled regulating valve; 12-Universal casters. Detailed Implementation

[0031] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0032] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the relative positions of the corresponding components in the direction of gravity when they are in use, and "inner" and "outer" refer to their relative positions to the contours of the corresponding components themselves. Furthermore, the terms "first," "second," etc., used in this disclosure are for distinguishing one element from another and do not have sequential or importance implications. In the following description, when referring to the accompanying drawings, unless otherwise explained, the same reference numerals in different drawings denote the same or similar elements.

[0033] Firstly, according to the embodiments of this application, reference is made to... Figures 1 to 4 A device for testing the atomization characteristics of a water-jet engine nozzle is provided. The device includes a frame 1 serving as a supporting base. A high-pressure liquid supply system integrated onto the frame 1 is configured to sequentially connect a high-pressure gas tank 4, a high-pressure liquid tank 5, and a liquid output main pipeline via pipelines. The high-pressure gas tank 4 can be a cylinder filled with high-pressure nitrogen or helium, and it pressurizes the liquid, such as water, stored in the high-pressure liquid tank 5.

[0034] Its working principle is as follows: the working medium in the combustion chamber of the water-jet engine is water under high pressure. To reproduce this core condition in a laboratory environment, the most direct method is to apply controllable high pressure to the liquid before it is sprayed out. Therefore, in this embodiment, a high-pressure gas tank 4 is used to pressurize the high-pressure liquid tank 5 to achieve spraying. The atomization observation box 2 is made of transparent material and is set on the frame 1, providing a visualization space for the formation and development of the spray field. The end of the liquid output main pipeline is equipped with a connection part, which can quickly install and replace different types of nozzles 6 to be tested, and accurately position the nozzles 6 in the optimal test position inside the observation box. The optical measurement system set around the observation box integrates a schlieren 7, a high-speed camera 8, and a laser particle size analyzer 9, forming a multi-dimensional, non-contact measurement network from macroscopic flow field to microscopic particle size. In addition, the flow rate control system composed of a flow meter 10 and an electronically controlled regulating valve 11 provides a basis for accurately controlling the stability of the liquid supply.

[0035] The technical solution of this embodiment has the following beneficial effects: it constructs a dedicated hardware platform with complete functions and high operating condition fidelity for the testing of the water-jet engine nozzle 6. It integrates high-pressure simulation, observation and measurement and control into one, fundamentally solving the measurement distortion problem caused by the mismatch of operating conditions in traditional devices, and laying a solid physical foundation for obtaining atomization data with high engineering guidance value.

[0036] It should be noted that the high-pressure gas tank 4 is not limited to high-pressure gas cylinders. Another feasible embodiment is a system combining an air compressor and a gas storage tank. The air compressor operates continuously, storing compressed air in the gas storage tank, which, after passing through a pressure regulating valve, can then supply gas to the high-pressure liquid tank 5 as a stable high-pressure gas tank 4.

[0037] According to the embodiments of this application, refer to Figure 1 and Figure 2 The laser particle size analyzer 9 includes a laser emitter 901 and a laser receiver 902, which are respectively set on the opposite side walls of the atomization observation box 2. They are not only at the same horizontal height, but the direction of their connection must be orthogonal to the central axis of the nozzle 6 installed on the connecting part.

[0038] The laser particle size analyzer 9 operates on the principle of laser diffraction or scattering, retrieving the droplet size spectrum by measuring the intensity distribution of the laser beam after it passes through the spray field. To obtain accurate data representing the overall atomization performance of the nozzle 6, the laser beam must pass through the most representative and stable region of the spray field—the region extending along the central axis of the nozzle 6. Positioning the laser emitter 901 opposite the receiver, with their line perpendicular to the axis of the nozzle 6, ensures the laser beam vertically and completely cuts through this core region, thus collecting the most representative sample. Requiring both to be at the same horizontal level ensures a horizontal measurement cross-section, helping to eliminate the influence of droplet settling due to gravity on the vertical concentration distribution. This allows each measurement to be performed under comparable spatial conditions, improving the repeatability and scientific validity of the data.

[0039] This layout offers the following advantages: it ensures the accuracy and reliability of the laser particle size analyzer 9's measurement results. Compared to random or coarse placement, this layout allows the obtained particle size distribution data to truly and directly reflect the atomization performance of the nozzle 6 in the core flow region, becoming a key quantitative basis for evaluating and optimizing the nozzle 6 design, and providing structural assurance for the device to achieve high-precision measurements.

[0040] According to the embodiments of this application, refer to Figure 1 and Figure 2 Furthermore, the schlieren spectrometer 7 and the high-speed camera 8 are positioned around the atomization observation box 2, and their optical paths and shooting angles are required to be independent of each other. This is a layout principle for achieving simultaneous, efficient, and independent operation of multiple optical diagnostic technologies. The schlieren spectrometer 7 is an optical system used to observe the density gradient of the flow field. It is very sensitive to stray light and requires a clear optical path and a stable dark field environment. The high-speed camera 8 is used to directly record the transient morphology and breakup process of the spray, requiring good illumination and a clear field of view. If the layout is inappropriate, the strong light source of the schlieren spectrometer 7 may become a source of light pollution for the high-speed camera 8, or the supplementary light of the high-speed camera 8 may illuminate the blade edge of the schlieren spectrometer 7, causing a simultaneous decrease in the image quality of both.

[0041] The technical solution of this embodiment requires that the two devices do not interfere with each other, which is achieved through systematic spatial planning to optimize the arrangement of the device's position, angle, and field of view. For example, the optical path of the schlieren 7 can be set on one side of the atomization observation box 2, while one or more high-speed cameras 8 can be arranged at a large angle to it, with independent operation and adjustment space reserved for each device. The purpose of this design is to ensure that each set of optical equipment can be completely independent in physical space and optical path when collecting data on the same spray event, without affecting each other.

[0042] The technical solution in this embodiment achieves true multi-parameter spatiotemporal synchronous measurement, ensuring a strict temporal correspondence and spatial correlation between the macroscopic density field image of the spray acquired by the schlieren 7 and the microscopic transient morphology image captured by the high-speed camera 8 at the same moment. This provides researchers with the possibility of directly linking macroscopic flow structures with microscopic fragmentation mechanisms for analysis, deepening the understanding of the atomization process and enhancing the information dimension of the test data.

[0043] According to the embodiments of this application, refer to Figure 1 and Figure 2 The atomization observation box 2 can also form a closed cavity, with an openable and closable sealed cover 201 on the top, and a ventilation interface 202 connected to a back pressure regulation system on the side wall or bottom of the atomization observation box 2.

[0044] The function of the back pressure regulation system is to actively regulate and maintain the pressure inside the atomization observation chamber 2 at a set simulated operating pressure. First, a sealed top cover 201 is installed to change the atomization observation chamber 2 from an open or semi-closed type to a closed type. This is not merely a formal closure; its fundamental purpose is to reproduce the physical boundary conditions of the engine combustion chamber. In a real engine, the spray develops within a finite-volume combustion chamber, constrained by the walls. Its spray cone angle, penetration distance, and other parameters are drastically different from those under conditions of free expansion in an infinitely large space. Therefore, a sealed cavity is a necessary prerequisite for obtaining macroscopic spray parameters with real engineering significance. However, simple sealing introduces a new problem: when liquid is continuously injected into the sealed space, the internal pressure will continuously rise, creating an unsteady environment that does not match the actual engine operating conditions. Therefore, this embodiment introduces a back pressure regulation system. The back pressure regulation system is connected to the sealed cavity through a vent 202. It can be a closed-loop control system consisting of a precision electronically controlled valve, a pressure sensor, and a vacuum pump or air compressor. Its working principle is as follows: A target back pressure value is set according to experimental needs. The system monitors the pressure inside the chamber in real time through a pressure sensor and adjusts the opening of the electronically controlled valve via a controller to control the flow rate of the extracted or replenished air, thereby dynamically stabilizing the pressure inside the atomization observation chamber 2 at the set value. This allows researchers to conduct tests in a controllable, stable, and accurately reproducible pressure environment. This structure elevates the atomization observation chamber 2 from a simple atomization observation chamber into an active operating condition simulator. This enables the device to accurately simulate the atomization characteristics of a water-ramjet engine at different operating depths or combustion chamber pressures. All optical measurement data obtained under these conditions are acquired in a specific, realistic, and stable pressure environment, providing high fidelity and direct engineering guidance for the design and optimization of water-ramjet engine injection systems.

[0045] For example, the back pressure regulation system can be a mechanically adjustable pressure relief valve, directly mounted on the vent 202. The relief pressure is set by adjusting the preload of the internal spring by rotating the valve cover. When the spray causes the pressure inside the chamber to exceed the set value, the valve automatically opens to release pressure; when the pressure is lower than the spring force, the valve closes. This solution is simple in structure and low in cost. Although its control accuracy and response speed are not as good as an electronic closed-loop system, it can still achieve the basic function of maintaining the pressure inside the chamber within a certain approximately stable range. It is suitable for test scenarios where the back pressure control accuracy requirements are not stringent, and it can also reflect the concept of simulating a closed back pressure environment of this application.

[0046] According to an embodiment of this application, the inner wall of the atomizing observation chamber 2 is coated with a hydrophobic film. This is a detailed optimization for a test environment using water as the working medium. When fine water mist is continuously sprayed onto the transparent inner wall of the observation chamber, it gradually condenses into water droplets of varying sizes or forms an uneven water film. These deposits can severely interfere with optical measurements. Water droplets act like lenses, distorting the imaging light behind them, leading to schlieren image distortion and high-speed image distortion; while the water film reduces the light transmittance of the observation window, causing overall image blurring and reduced contrast. The hydrophobic film, for example, uses Teflon, utilizing its extremely low surface energy. When water droplets impact the wall surface covered with the hydrophobic film, they are difficult to spread out, but tend to maintain a high contact angle, gather into beads, and quickly roll down the wall surface to the drainage structure at the bottom of the chamber. This reduces the number of droplets adhering to the observation window area and their residence time. It significantly and persistently ensures the high-definition field of view required for optical measurements. By maintaining the continuous cleanliness and transparency of the observation window, clear, stable, and optically distortion-free image data is ensured for both high-speed photography and schlieren imaging throughout the entire experimental period, thereby improving the accuracy and reliability of the final measurement results. Simultaneously, it reduces the frequency of interruptions for manual cleaning due to blurred vision, improving the continuity and overall efficiency of the testing process.

[0047] According to an embodiment of this application, the outer wall of the atomization observation box 2 is provided with a diffuser for providing backlight.

[0048] This embodiment is based on the requirement for high-quality photographic light sources, primarily serving to optimize the imaging quality of the high-speed camera 8, especially by employing backlighting, such as shadow techniques, to capture droplet silhouettes. To clearly distinguish the edges and filamentous structures of tiny droplets moving at high speeds, the illumination source needs sufficient brightness, uniformity, and suitable light quality. Ordinary point light sources or unprocessed strip light sources produce harsh highlights, deep shadows, and obvious brightness gradients, which obscure much detail. A diffuser, typically a milky-white acrylic sheet or a professional diffuser material, transforms the direct light emitted by a primary light source placed behind it, such as LED strips or flat panel lights, into a large-area, uniformly bright diffused surface light source. Specifying "backlighting" means placing the light source opposite the subject, i.e., the spray, with the camera shooting from the other side, creating backlighting that yields highly contrasting droplet silhouettes.

[0049] The diffuser in this embodiment creates near-ideal lighting conditions for high-speed photography, producing high-quality images with soft shadows, rich details, and uniform overall illumination. This allows key transient features such as the precise size of droplets, the fine filaments and droplets generated by breakup to be clearly recorded, thereby improving the accuracy and reliability of image-based quantitative measurements, such as particle size statistics and breakup frequency analysis. It is an indispensable auxiliary structure for obtaining high-quality transient process data.

[0050] It should be noted that the soft light effect can also be achieved by setting up a light box on the outside of the observation box. The interior of this light box is filled with light sources, and the exit surface is covered with a diffuser plate. Its principle is similar to that of a single diffuser plate, but it can provide a larger area and more uniform illumination, making it especially suitable for large observation boxes.

[0051] According to the embodiments of this application, refer to Figure 2 The flow rate control system also includes a controller 3. The flow meter 10 and the electrically controlled regulating valve 11 are both connected to the controller 3. The controller 3 adjusts the opening of the electrically controlled regulating valve 11 according to the flow feedback signal, thereby forming a closed-loop control.

[0052] This is a technical means to achieve high-precision and high-repeatability control of experimental conditions. Its working principle is based on the closed-loop feedback principle in automatic control theory. Before the experiment begins, the operator sets the target liquid flow rate value through the interface of controller 3. When the system is running, the flow meter 10 installed on the main pipeline, such as the electromagnetic flow meter 10 or the mass flow meter 10, acts as a sensor to continuously measure the actual volumetric flow rate or mass flow rate in the pipeline in real time, and feeds this electrical signal back to controller 3. The program inside controller 3 compares the received actual flow signal with the preset target flow rate value in real time and calculates the current flow deviation. Then, controller 3 generates corresponding control commands based on the magnitude and direction of the deviation and sends them to the electrically controlled regulating valve 11. The electrically controlled regulating valve 11 precisely adjusts the opening of its valve core according to the received commands, thereby changing the liquid flow area through the pipeline, and ultimately stabilizing the actual flow rate within the allowable error range of the target flow rate value. The value of this closed-loop logical reasoning lies in its dynamic adjustment capability. It can proactively overcome and compensate for various interference factors in the system that may cause flow fluctuations, such as the slow decrease in pressure of high-pressure tank 5, minor pump pulsations, or viscosity changes caused by fluid temperature variations. Therefore, it provides extremely accurate and highly consistent liquid supply conditions for each independent test, as well as comparative tests of the same nozzle 6 under different operating conditions. This ensures the scientific rigor and high reliability of the experimental results.

[0053] According to the embodiments of this application, refer to Figure 2 The controller 3 is also connected to the pressure sensor 501 and temperature sensor 502 installed on the high-pressure liquid tank 5 for monitoring and recording operating parameters.

[0054] This design extends the device's intelligent measurement and control capabilities from a single flow closed loop to digital monitoring of the entire high-pressure liquid supply system. A scientific atomization characteristic test requires not only the spray images and particle size data captured by the optical system, but also the precise operating conditions at which the spray is generated. Pressure sensor 501 monitors the pressure inside the high-pressure liquid tank 5 in real time. This pressure directly determines the liquid pressure supplied to the nozzle 6 and is one of the most critical parameters affecting atomization. Temperature sensor 502 monitors the liquid temperature, as the viscosity, surface tension, and other physical properties of the liquid change with temperature, thus affecting the atomization and breakup process. By connecting the signals from these two key sensors to the same controller 3, firstly, it achieves synchronous acquisition and correlation of multiple parameters. Controller 3 can synchronously record the change curves of flow rate, pressure, and temperature with a unified timestamp and align them with the signals triggered by the optical equipment. This assigns a complete operating condition "tag" to each atomization data frame, making subsequent data analysis, model verification, and report generation extremely accurate and convenient. Secondly, it lays the foundation for future implementation of more advanced multi-variable collaborative control. For example, complex test procedures such as constant pressure and variable flow or constant flow and variable pressure can be programmed, further improving the automation level and testing efficiency of the device.

[0055] According to the embodiments of this application, refer to Figure 2 The water-jet engine nozzle atomization characteristic test apparatus also includes a spare branch air pipe 401. The outlet end of this branch air pipe 401 is guided to the vicinity of the connection part to provide auxiliary gas for the gas-liquid two-phase flow nozzle 6 installed on the connection part. The nozzle 6 under test also includes a gas-liquid two-phase flow nozzle 6. The atomization mechanism of such nozzles 6 (such as air-assisted atomizing nozzles 6) not only relies on the high pressure of the liquid, but also requires one or more auxiliary gas jets to interact with the liquid jet from a specific angle, using pneumatic shear force to greatly enhance the liquid atomization effect, thereby obtaining finer droplets. The spare branch air pipe 401 is an independent air passage specially set up to introduce this auxiliary gas. It is usually connected to a low-pressure or medium-pressure gas source, and the gas parameters are controlled by a precision valve and flow meter 10.

[0056] The beneficial effects of this embodiment are as follows: It upgrades the experimental device of this application from a single liquid pressure atomization test platform to a comprehensive test platform compatible with the gas-assisted atomization principle. Users only need to install the two-phase flow nozzle 6 onto the universal connector and connect the spare branch gas pipe 401 to easily study the influence of key parameters such as gas pressure and gas-liquid flow ratio on atomization performance. This greatly enhances the versatility and research value of the device, enabling it to support a wider range of nozzle 6 technology research and providing a more comprehensive experimental means for selecting the optimal atomization scheme for water-ramjet engines.

[0057] According to the embodiments of this application, refer to Figure 2 The frame 1 has casters 12 with locking function at the bottom. A test apparatus integrating a high-pressure gas tank 4, a high-pressure liquid tank 5, an optical measurement system, and a flow rate control system is typically quite heavy and bulky. Fixed installation would occupy permanent space and would be inconvenient for repositioning for maintenance or integration with other equipment. Installing casters 12 with locking brakes at the bottom of the frame 1 allows the entire apparatus to be easily moved to a suitable location in the laboratory, like a cart. Once positioned, the brakes can be applied to securely lock it in place, preventing slippage and ensuring stability during testing.

[0058] Secondly, a method for testing the atomization characteristics of a water-jet engine nozzle using the aforementioned testing apparatus is provided, comprising the following steps:

[0059] S1: Install the nozzle to be tested to the connection part and position it at the test position inside the atomization observation box, then close the sealing cover;

[0060] S2: Activate the back pressure regulation system to adjust and stabilize the internal pressure of the atomization observation box to the set simulated working condition pressure;

[0061] S3: Control the high-pressure gas tank to pressurize the liquid in the high-pressure liquid tank, and adjust and stabilize the liquid flow rate to a set value through the flow rate control system;

[0062] S4: High-pressure liquid is supplied to the nozzle under test to form a spray field, and the optical measurement system is triggered to perform synchronous data acquisition at the same time.

[0063] S5: The data collected by the optical measurement system includes: macroscopic density field image of the spray obtained by the schlieren, transient morphology image of the spray obtained by the high-speed camera, and droplet size distribution data obtained by the laser particle size analyzer.

[0064] Optionally, in step S4, when the nozzle to be tested is a gas-liquid two-phase flow nozzle, auxiliary gas with set parameters is also provided to the nozzle through the backup branch gas pipe.

[0065] Optionally, in step S3, the controller synchronously records the liquid flow rate, the pressure and temperature inside the high-pressure liquid tank, and the pressure data inside the atomization observation box, and adds corresponding timestamps and operating condition tags to the data frames collected by the optical measurement system.

[0066] Optionally, in step S2, the back pressure regulation system maintains the internal pressure of the atomization observation box at a set value that is higher or lower than the ambient atmospheric pressure.

[0067] refer to Figures 1 to 4The following describes a specific embodiment and its complete working process to illustrate the working principle of the water jet engine nozzle atomization characteristic test device of this application.

[0068] The structure of the device in this embodiment is as follows: Figure 1 and Figure 2 As shown, a robust aluminum frame 1 forms the main body of the device, with four casters 12 equipped with brakes at the bottom. The upper layer of the frame 1 integrates a high-pressure liquid supply system: a high-pressure gas tank 4 serves as the high-pressure gas source, connected to the top inlet of a high-pressure liquid tank 5 via a pressure reducing valve and a pressure regulating valve; a centrifugal water pump acts as the liquid supply unit, injecting water into the high-pressure liquid tank 5; the bottom outlet of the high-pressure liquid tank 5 connects to the main liquid output pipeline. A high-precision mass flow meter 10 and an electrically controlled regulating valve 11 are sequentially installed on the main pipeline, their signal lines connected to an industrial touchscreen controller 3. A pressure sensor 501 and a temperature sensor 502 are also installed on the liquid tank, their signals also connected to the controller 3. The end of the main pipeline is a standard external threaded connector.

[0069] A fogging observation box 2, made of thick acrylic sheet, is installed in the middle of frame 1. The top of fogging observation box 2 is fitted with an aluminum alloy cover with a sealing ring, which can be tightly closed with a quick-lock handle. A ventilation port 202 is located on the lower side of one side of fogging observation box 2, connected via a hose to a back pressure regulation system. This system consists of a miniature vacuum pump, a precision needle valve, and an internal pressure sensor, and is managed by controller 3. All inner walls of fogging observation box 2 are lined with a Teflon hydrophobic membrane. At the rear of fogging observation box 2, an LED diffuser panel is installed, emitting cool white light.

[0070] The layout of the optical measurement system is as follows Figure 2 As shown: The laser emitter 901 and laser receiver 902 of a laser particle size analyzer 9 are adjusted to face the transparent windows on the left and right side walls of the atomization observation box 2, respectively, with their centers at the same height. The laser beam passes horizontally, and its preset optical path is perpendicular to the axis of the nozzle 6 to be installed. A schlieren spectrometer 7 is placed on the right side of the atomization observation box 2. A high-speed camera 8 is set at the rear of the atomization observation box 2, aimed at the internal spray area, ensuring that its field of view does not overlap with the schlieren optical path.

[0071] The work process is as follows:

[0072] Installation and Preparation: The operator screws the single-hole pressure atomizing nozzle 6 to be tested onto the threaded connector at the end of the liquid output main pipeline. Open the sealing cover 201 of the atomization observation box 2, and manually adjust the mounting plate (up, down, left, right) using the fine-tuning mechanism until the nozzle 6 outlet is at the geometric center of the observation box. Then close and lock the sealing cover 201. Next, finely adjust the laser particle size analyzer 9 to ensure the laser beam accurately passes through the estimated spray center area; adjust the focal length and angle of the high-speed camera 8 to ensure its field of view clearly covers the entire spray cone angle range.

[0073] Operating Condition Setup: Using the interface of controller 3, start the water pump to fill the high-pressure liquid tank 5 with water to the predetermined level and then stop. Next, set the target parameters for this experiment. Controller 3 first controls the back pressure regulation system, starting the vacuum pump and stabilizing the pressure inside the atomization observation box 2 at the set value through the adjustment of the needle valve. Then, open the valve of the high-pressure gas tank 4. Based on the feedback from the pressure sensor 501 of the high-pressure liquid tank 5, controller 3 automatically adjusts the inlet pressure regulating valve to ensure the pressure in the high-pressure liquid tank 5 rises smoothly and stabilizes at the set value. Simultaneously, based on the feedback from the mass flow meter 10, controller 3 dynamically adjusts the opening of the electronically controlled regulating valve 11 to precisely stabilize the main pipeline flow rate at the set flow rate.

[0074] Test execution and synchronous data acquisition: The operator clicks the start button on controller 3. While recording operating data, controller 3 sends a synchronous trigger signal. This signal commands the opening of the fast solenoid valve at the front end of nozzle 6, instantly spraying high-pressure water into the atomization observation box 2 to form a spray field; simultaneously, this signal synchronously triggers the laser particle size analyzer 9, two high-speed cameras 8, and the schlieren 7 to begin acquiring data.

[0075] During the 2 seconds of spraying, the laser particle size analyzer 9 continuously collects diffraction intensity data at a rate of 1 kHz per second, calculates and uploads the droplet size distribution in real time.

[0076] The high-speed camera 8 synchronously records the development and near-field breakup of the spray at a rate of 100,000 frames per second.

[0077] The Schlieren 7 recorded density variation shadow maps of the spray field at a rate of 5,000 frames per second.

[0078] Controller 3 synchronously records the real-time curves of flow rate, tank pressure, temperature, and back pressure in the tank on the time axis.

[0079] End and Follow-up: When the preset spray time ends, controller 3 closes the rapid solenoid valve, and spraying stops. The back pressure regulation system maintains the environment inside the chamber. The operator can review all synchronized sensor data and image previews on controller 3. One test is complete. If it is necessary to replace the nozzle with a gas-liquid two-phase flow nozzle 6 for testing, when installing the new nozzle 6, align the outlet of the spare branch air pipe 401 with the inlet of the nozzle 6, set the corresponding gas flow parameters in controller 3, and repeat the above process.

[0080] Through this complete workflow, this embodiment clearly demonstrates how the water jet engine nozzle atomization characteristic test device of this application seamlessly integrates high-pressure liquid precise generation, simulated environment active control, multi-optical synchronous trigger acquisition, and unified management of the entire process data.

[0081] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0082] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0083] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A test apparatus for the atomization characteristics of a water-jet engine nozzle, characterized in that, include: Framework (1); A high-pressure liquid supply system is integrated on the frame (1), which includes a high-pressure gas tank (4), a high-pressure liquid tank (5) and a liquid output main pipeline connected in sequence by pipelines. The high-pressure gas tank (4) is used to pressurize the liquid in the high-pressure liquid tank (5). The atomization observation box (2) is a closed cavity made of transparent material, which is set on the frame (1). It has an openable and closable sealed cover (201) on the top and ventilation ports (202) on the side walls or bottom. A back pressure regulation system, connected to the ventilation port (202), is used to regulate and maintain the pressure inside the atomization observation box (2); The end of the liquid output main pipeline is provided with a connecting part for detachably installing the nozzle (6) to be tested, and so that the outlet of the nozzle (6) is located in the test position inside the atomization observation box (2); The optical measurement system includes a schlieren (7), a high-speed camera (8), and a laser particle size analyzer (9) disposed on the periphery of the atomized observation box (2); and, The flow rate control system includes a flow meter (10) and an electrically controlled regulating valve (11) installed on the liquid output main pipeline.

2. The experimental apparatus according to claim 1, characterized in that, The laser particle size analyzer (9) includes a laser emitter (901) and a laser receiver (902). The laser emitter (901) and the laser receiver (902) are respectively set on the opposite side walls of the atomization observation box (2) and are at the same horizontal height. The direction of their connection is orthogonal to the central axis of the nozzle (6) installed on the connecting part. The schlieren (7) and the high-speed camera (8) are set around the atomization observation box (2), and their optical paths and shooting angles do not interfere with each other.

3. The experimental apparatus according to claim 1, characterized in that, The inner wall of the fogging observation box (2) is covered with a hydrophobic film; and / or, the outer wall of the fogging observation box (2) is provided with a diffuser for providing backlight to the high-speed camera (8).

4. The experimental apparatus according to claim 1, characterized in that, The flow rate control system also includes a controller (3); the flow meter (10), the electrically controlled regulating valve (11), and the pressure sensor (501) and temperature sensor (502) installed on the high-pressure liquid tank (5) are all connected to the controller (3); the controller (3) is used to adjust the opening of the electrically controlled regulating valve (11) according to the feedback signal of the flow meter (10) to control the flow rate, and to simultaneously monitor and record pressure and temperature parameters.

5. The test apparatus according to claim 1, characterized in that, The test apparatus also includes a spare branch gas pipe (401), the outlet of which is guided to the vicinity of the connection part to provide auxiliary gas for the gas-liquid two-phase flow nozzle (6) installed on the connection part.

6. The testing apparatus according to any one of claims 1 to 5, characterized in that, The frame (1) is equipped with a universal wheel (12) with locking function at the bottom.

7. A test method for testing the atomization characteristics of a water-jet engine nozzle using the test apparatus as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Install the nozzle to be tested to the connection part and position it at the test position inside the atomization observation box, then close the sealing cover; S2: Activate the back pressure regulation system to adjust and stabilize the internal pressure of the atomization observation box to the set simulated working condition pressure; S3: The flow rate control system controls the high-pressure gas tank to pressurize the liquid in the high-pressure liquid tank and adjusts and stabilizes the liquid flow rate to the set value; S4: High-pressure liquid is supplied to the nozzle under test to form a spray field, and the optical measurement system is triggered to perform synchronous data acquisition at the same time. S5: The data collected by the optical measurement system includes: macroscopic density field image of the spray obtained by the schlieren, transient morphology image of the spray obtained by the high-speed camera, and droplet size distribution data obtained by the laser particle size analyzer.

8. The test method according to claim 7, characterized in that, In step S4, when the nozzle to be tested is a gas-liquid two-phase flow nozzle, auxiliary gas with set parameters is also provided to the nozzle through the backup branch gas pipe.

9. The test method according to claim 7, characterized in that, In step S3, the controller synchronously records the liquid flow rate, the pressure and temperature inside the high-pressure liquid tank, and the pressure data inside the atomization observation box, and adds corresponding timestamps and operating condition tags to the data frames collected by the optical measurement system.

10. The test method according to claim 7, characterized in that, In step S2, the back pressure regulation system maintains the internal pressure of the atomization observation box at a set value that is higher or lower than the ambient atmospheric pressure.

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