Measuring device and method for the initial flow field at the exit of a shock wave simulator

Abstract

The application discloses a kind of measuring device and method for the initial flow field of explosion wave simulation device outlet, to solve the problem that prior art cannot accurately measure the transient initial flow field at the outlet of explosion wave simulation device. Specifically includes 1# pressure sensor, 2# pressure sensor, oscilloscope, synchronizer and particle image velocimetry system;1# pressure sensor and 2# pressure sensor are sequentially installed on the upstream of explosion wave simulation device outlet along the flow direction of tracer particle, and 1# pressure sensor and 2# pressure sensor are respectively connected with the signal acquisition end of oscilloscope;The signal output end of oscilloscope is connected with the signal input end of synchronizer;The signal output end of synchronizer is connected with the signal input end of particle image velocimetry system;Synchronizer sends start signal to particle image velocimetry system according to the trigger signal received and the delay time Δtau set in synchronizer;Particle image velocimetry system is started according to the start signal, so as to obtain the initial flow field image at the outlet of explosion wave simulation device.

Description

Technical Field

[0001] This invention relates to a device and method for measuring the flow field of shock waves, and more specifically to a device and method for measuring the initial flow field at the outlet of an explosion wave simulation device. Background Technology

[0002] An explosion wave simulator is an important experimental platform for simulating explosion shock waves. It can generate and control shock waves and can be used to study the shock wave damage effects on buildings, vehicles, and other structures. The simulator consists of a high-pressure section, a transition section, and a test section. A diaphragm separates high-pressure and low-pressure gases. During operation, the diaphragm ruptures instantaneously, allowing the high-pressure gas to flow out from the high-pressure end, accelerate through a nozzle, and enter the test section. After the shock wave passes the downstream outlet, the gas pressure inside the pipe is higher than the ambient pressure. A rarefaction wave is generated at the outlet to balance the internal and external pressures. This rarefaction wave propagates upstream, causing a decrease in static pressure inside the pipe, accelerated flow, and a shortened duration of the shock wave's positive pressure. To eliminate the influence of the rarefaction wave at the outlet, a rarefaction wave elimination device is often installed at the outlet of the explosion wave simulator to control the outlet area and match the outlet gas pressure with the ambient pressure. Obtaining flow field information at the outlet of the explosion wave simulator is crucial during the development and evaluation of the rarefaction wave elimination device. However, the gas flow state at the outlet of the explosion wave simulator is difficult to observe directly and requires the use of flow visualization methods.

[0003] The interaction between high-speed airflow and the rarefaction wave elimination device at the outlet of the explosion wave simulator generates shock waves, expansion waves, and a mixing layer. Schlieren and shading methods are effective at capturing shock waves, but struggle to capture expansion waves and the mixing layer. Particle image velocimetry (PIV) is a non-contact laser-based method for diagnosing the initial flow field. It acquires a two-dimensional image of the flow field by seeding tracer particles in the flow field and illuminating them with a laser. After the shock wave front passes, stationary particles in the flow field acquire velocities along the flow direction. However, tracer particles can only be seeded inside the test section, making it difficult to seed them outside the outlet of the explosion wave simulator. Furthermore, explosion wave simulators differ from ordinary wind tunnels, operating for extremely short periods (typically tens of milliseconds), and current PIV systems generally operate at frequencies not exceeding 20 Hz. Therefore, it is impossible to accurately measure the transient initial flow field at the outlet of the explosion wave simulator. Summary of the Invention

[0004] The purpose of this invention is to provide a measuring device and method for the initial flow field at the outlet of an explosion wave simulation device, so as to solve the technical problem that the prior art cannot accurately measure the transient initial flow field at the outlet of the explosion wave simulation device.

[0005] To achieve the above objectives, the present invention provides a measuring device for the initial flow field at the outlet of an explosion wave simulation device, which is characterized by including a pressure sensor #1, a pressure sensor #2, an oscilloscope, a synchronizer, and a particle image velocimetry system.

[0006] The pressure sensor #1 and pressure sensor #2 are installed sequentially upstream of the outlet of the explosion wave simulation device along the direction of tracer particle flow. The pressure sensor #1 and pressure sensor #2 are respectively connected to the signal acquisition terminal of the oscilloscope.

[0007] The signal output terminal of the oscilloscope is connected to the signal input terminal of the synchronizer. The oscilloscope is used to acquire the intermittent pressure signals of pressure sensor #1 and pressure sensor #2, and simultaneously record the intermittent pressure signals and send a trigger signal to the synchronizer.

[0008] The signal output terminal of the synchronizer is connected to the signal input terminal of the particle image velocimetry system.

[0009] The synchronizer sends a start signal to the particle image velocimetry system based on the received trigger signal and the delay time Δτ set within the synchronizer; the particle image velocimetry system starts according to the start signal, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device;

[0010] Alternatively, the synchronizer synchronously sends a start signal to the particle image velocimetry system based on the received trigger signal; the particle image velocimetry system starts according to the start signal and the delay time Δτ set in the particle image velocimetry system, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device.

[0011] Furthermore, the delay time Δτ is the time difference between the time it takes for pressure sensor #1 to receive the intermittent pressure signal and the start-up time of the particle image velocimetry system, and this time difference is calculated by the following formula:

[0012]

[0013] In the formula, t1 and t2 are the times when pressure sensor #1 and pressure sensor #2 receive the intermittent pressure signal, ΔL is the distance between pressure sensor #1 and pressure sensor #2, and L is the distance between pressure sensor #1 and the outlet of the explosion wave simulation device. Test τ' represents the width of the observation area for the tracer particles, v represents the velocity of the tracer particles after the shock wave, and τ′ represents the inherent delay time of the particle image velocimetry system.

[0014] Furthermore, the particle image velocimetry system includes a synchronization controller, a CCD camera, and a laser;

[0015] The signal input terminal of the synchronization controller is connected to the signal output terminal of the synchronization machine, and the control output terminal of the synchronization controller is connected to the CCD camera and the laser respectively; when the delay time Δτ is set inside the particle image velocimetry system, it is specifically set inside the synchronization controller;

[0016] The CCD camera and laser are respectively set on both sides of the outlet of the explosion wave simulation device. The laser output end of the laser corresponds to the outlet of the explosion wave simulation device and is used to illuminate the outlet area of ​​the explosion wave simulation device. The image acquisition area of ​​the CCD camera corresponds to the outlet area of ​​the explosion wave simulation device illuminated by the laser and is used to acquire the initial flow field image at the outlet of the explosion wave simulation device.

[0017] Furthermore, it also includes a tracer particle dissemination system;

[0018] The tracer particle dispersing system is used to uniformly disperse tracer particles into the interior of the explosion wave simulation device.

[0019] The present invention also provides a method for measuring the initial flow field at the outlet of an explosion wave simulation device, using the aforementioned measuring device for the initial flow field at the outlet of an explosion wave simulation device, characterized by the following steps:

[0020] Step 1: Set a delay time Δτ in the synchro (4) or particle image velocimetry system; and seed tracer particles into the explosion wave simulation device;

[0021] Step 2: Run the explosion wave simulation device. The shock wave propagates to pressure sensor #1 and pressure sensor #2. Pressure sensor #1 and pressure sensor #2 respectively collect the pressure discontinuity signal upstream of the outlet of the explosion wave simulation device and send it to the oscilloscope.

[0022] Step 3: The oscilloscope records the pressure discontinuity signal and sends a trigger signal to the synchronizer (4);

[0023] Step 4: The synchronizer (4) sends a start signal to the particle image velocimetry system according to the trigger signal and the delay time Δτ; the particle image velocimetry system starts according to the start signal, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device;

[0024] Alternatively, the synchronizing machine (4) sends a start signal to the particle image velocimetry system according to the received trigger signal; the particle image velocimetry system starts according to the start signal and the delay time Δτ, thereby obtaining the initial flow field image at the outlet of the explosion wave simulation device.

[0025] Further, the delay time Δτ mentioned in step 1 is the time difference between the time when pressure sensor #1 receives the intermittent pressure signal and the start time of the particle image velocimetry system, and this time difference is calculated by the following formula:

[0026]

[0027] In the formula, t1 and t2 are the times when pressure sensors #1 and #2 receive intermittent pressure signals, ΔL is the distance between pressure sensors #1 and #2, and L is the distance from pressure sensor #1 to the outlet of the explosion wave simulation device. Test The width of the tracer particle observation area, v is the tracer particle velocity after the shock wave, and τ′ is the inherent delay time of the particle image velocimetry system.

[0028] Furthermore, the particle image velocimetry system includes a synchronization controller, a CCD camera, and a laser;

[0029] In step 1, when the delay time Δτ is set within the particle image velocimetry system, it is specifically set within the synchronization controller;

[0030] The particle image velocimetry system described in step 4 is started according to the start signal and the delay time Δτ. Specifically, the synchronous controller controls the camera and laser to start working according to the start signal and the delay time Δτ, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device.

[0031] Furthermore, step 1 is preceded by:

[0032] The explosion wave simulation device is operated, and the shock wave propagates to pressure sensor #1 and pressure sensor #2. Pressure sensor #1 and pressure sensor #2 respectively collect the pressure discontinuity signal upstream of the outlet of the explosion wave simulation device and send it to the oscilloscope.

[0033] The oscilloscope records the pressure discontinuity signal; the delay time Δτ is calculated based on the pressure discontinuity signal recorded by the oscilloscope.

[0034] The beneficial effects of this invention are:

[0035] This invention, by setting pressure sensors #1 and #2 upstream of the outlet of the explosion wave simulation device, can calculate the start-up delay time of the particle image velocimetry system. By setting the delay of the particle image velocimetry system, the contact surface between the gas inside the explosion wave simulation device and the external air can be accurately captured. With the help of data post-processing, information such as the velocity field, vorticity field, and flow field boundary of the transient initial flow field at the outlet can be obtained, thus realizing the measurement of the initial flow field parameters at the outlet of the explosion wave simulation device. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of an embodiment of a measuring device for the initial flow field at the outlet of an explosion wave simulation device according to the present invention;

[0037] Figure 2 This is a schematic diagram illustrating the principle of initial flow field delay at the outlet of the explosion wave simulation device in this embodiment of the invention.

[0038] Icon labels:

[0039] 1-Explosion wave simulation device, 2-Particle image velocimetry system, 21-Synchronization controller, 22-CCD camera, 23-Laser, 31-Pressure sensor #1, 32-Pressure sensor #2, 4-Synchronizer, 5-Oscilloscope. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1:

[0042] A measuring device for the initial flow field at the outlet of an explosion wave simulation device is disclosed. This device is used to observe the initial shock wave flow field at the outlet of an open explosion wave simulation device 1. The explosion wave simulation device 1 includes a high-pressure section, a transition section, and a test section. The high-pressure section is filled with high-pressure gas and is separated from the atmospheric pressure air in the test section by a diaphragm. The explosion wave simulation device 1 can generate shock waves that rupture the diaphragm. This measuring device can be applied to the development and evaluation of rarefaction wave elimination devices for explosion wave simulation devices.

[0043] Combination Figure 1 and Figure 2 As shown, the measuring device includes a tracer particle dispersal system, a pressure sensor 31 (1#), a pressure sensor 32 (2#), an oscilloscope 5, a synchronizer 4, and a particle image velocimetry system 2; the particle image velocimetry system 2 includes a synchronization controller 21, a CCD camera 22, and a laser 23; the particle image velocimetry system is used to acquire particle image information.

[0044] The tracer particle seeding system is used to uniformly seed tracer particles into the interior of an explosion wave simulation device.

[0045] Pressure sensors 31 (#1) and 32 (#2) are sequentially installed upstream of the outlet of the explosion wave simulation device 1 along the direction of tracer particle flow. Pressure sensors 31 and 32 are connected to the signal acquisition terminals of oscilloscope 5. The signal output terminal of oscilloscope 5 is connected to the signal input terminal of synchronizer 4. Oscilloscope 5 acquires the intermittent pressure signals collected by pressure sensors 31 and 32, records these signals, and sends a trigger signal to synchronizer 4. The signal output terminal of synchronizer 4 is connected to the signal input terminal of synchronization controller 21. Synchronizer 4 sends a trigger signal to synchronizer 21 based on the received trigger signal and the set delay time Δτ. Synchronous controller 21 sends a start signal; the control output terminal of synchronous controller 21 is connected to CCD camera 22 and laser 23 respectively. Synchronous controller 21 controls CCD camera 22 and laser 23 to start working according to the start signal; CCD camera 22 and laser 23 are respectively set on both sides of the outlet of the explosion wave simulation device. The laser output terminal of laser 23 corresponds to the outlet of explosion wave simulation device 1. Laser 23 is used to irradiate the outlet area of ​​explosion wave simulation device 1. The image acquisition area of ​​CCD camera 22 corresponds to the outlet area of ​​explosion wave simulation device 1 irradiated by laser 23. CCD camera 22 is used to acquire the initial flow field image at the outlet of explosion wave simulation device 1.

[0046] The specific measurement method is as follows:

[0047] Step 1: Set a delay time Δτ within the synchronizing machine 4; and seed tracer particles into the explosion wave simulation device 1 via the tracer particle seeding system; this delay time allows the explosion wave simulation device 1 to run before Step 1, and the shock wave propagates to pressure sensor 1# 31 and pressure sensor 2# 32. Pressure sensor 1# 31 and pressure sensor 2# 32 respectively collect the pressure discontinuity signal upstream of the outlet of the explosion wave simulation device 1 and send it to oscilloscope 4; oscilloscope 5 records the pressure discontinuity signal; calculate the delay time Δτ based on the pressure discontinuity signal recorded by oscilloscope 5. This delay time Δτ is the time difference between the time when pressure sensor 1# 31 receives the pressure discontinuity signal and the time when the synchronizing controller 21 controls the CCD camera 22 and laser 23 to start working, calculated by the following formula:

[0048]

[0049] In the formula, t1 and t2 are the peak pressure times of pressure sensor 1# 31 and pressure sensor 2# 32, ΔL is the distance between pressure sensor 1# 31 and pressure sensor 2# 32, and L is the distance of pressure sensor 1# 31 from the outlet of the explosion wave simulation device 1. Test τ' represents the width of the observation area for the tracer particles, v represents the velocity of the tracer particles after the shock wave, and τ′ represents the inherent delay time of the particle image velocimetry system.

[0050] Step 2: Run the explosion wave simulation device 1. The shock wave propagates to pressure sensor 31 and pressure sensor 32. Pressure sensor 31 and pressure sensor 32 collect the pressure discontinuity signal at the outlet of explosion wave simulation device 1 and send it to oscilloscope 5.

[0051] Step 3: Oscilloscope 5 records the pressure discontinuity signal and sends a trigger signal to synchronizer 4;

[0052] Step 4: Synchronizer 4 sends a start signal to particle image velocity measurement system 2 according to the trigger signal and the delay time Δτ; Synchronizer 21 starts according to the start signal, thereby acquiring the initial flow field image at the outlet of explosion wave simulation device 1.

[0053] This method is applicable to the measurement of transient initial flow field at the outlet of an explosion wave simulator and can capture the initial flow field at the outlet of the explosion wave simulator using the PIV method.

[0054] Example 2:

[0055] This embodiment is basically the same as the first embodiment, except that the delay time Δτ is set in the synchronization controller 21; finally, the synchronization controller 21 controls the camera 22 and the laser 23 to start working according to the start signal sent by the synchronizer 4 and the delay time Δτ, so as to obtain the initial flow field image of the outlet of the explosion wave simulation device 1.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A measuring device for the initial flow field at the outlet of an explosion wave simulation device, characterized in that: It includes a pressure sensor 1 (31), a pressure sensor 2 (32), an oscilloscope (5), a synchronizer (4), and a particle image velocimetry system (2); The pressure sensor 1 (31) and pressure sensor 2 (32) are installed sequentially upstream of the outlet of the explosion wave simulation device (1) along the direction of tracer particle flow. The pressure sensor 1 (31) and pressure sensor 2 (32) are respectively connected to the signal acquisition terminal of the oscilloscope (5). The signal output terminal of the oscilloscope (5) is connected to the signal input terminal of the synchro (4). The oscilloscope (5) is used to acquire the pressure discontinuity signals of pressure sensor 1 (31) and pressure sensor 2 (32), and at the same time record the pressure discontinuity signals and send a trigger signal to the synchro (4). The signal output terminal of the synchronizer (4) is connected to the signal input terminal of the particle image velocimetry system (2); The synchronizer (4) determines the time based on the received trigger signal and the delay time set within the synchronizer (4). A start signal is sent to the particle image velocimetry system (2); the particle image velocimetry system (2) is activated according to the start signal, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device (1); Alternatively, the synchronizer (4) synchronously sends a start signal to the particle image velocimetry system (2) based on the received trigger signal; the particle image velocimetry system (2) then sends a start signal based on the start signal and the delay time set within the particle image velocimetry system (2). Start up to obtain the initial flow field image at the outlet of the explosion wave simulation device (1); The delay time The time difference between the time when pressure sensor #1 (31) receives the intermittent pressure signal and the start-up time of the particle image velocimetry system (2) is calculated by the following formula: ； In the formula, The time it takes for pressure sensor #1 (31) and pressure sensor #2 (32) to receive intermittent pressure signals is given. The distance between pressure sensor #1 (31) and pressure sensor #2 (32) is... The distance between pressure sensor #1 (31) and the outlet of the explosion wave simulation device (1) is... To determine the width of the observation area for tracer particles, The velocity of the tracer particles after the shock wave. This is the inherent delay time of the particle image velocimetry system.

2. The measuring device for the initial flow field at the outlet of an explosion wave simulation device according to claim 1, characterized in that: The particle image velocimetry system (2) includes a synchronization controller (21), a CCD camera (22), and a laser (23). The signal input terminal of the synchronization controller (21) is connected to the signal output terminal of the synchronization machine (4), and the control output terminal of the synchronization controller (21) is connected to the CCD camera (22) and the laser (23) respectively; when the delay time When set inside the particle image velocimetry system (2), it is specifically set inside the synchronization controller (21); The CCD camera (22) and laser (23) are respectively set on both sides of the outlet of the explosion wave simulation device (1). The laser output end of the laser (23) corresponds to the outlet of the explosion wave simulation device (1) and is used to irradiate the outlet area of ​​the explosion wave simulation device (1). The image acquisition area of ​​the CCD camera (22) corresponds to the outlet area of ​​the explosion wave simulation device (1) irradiated by the laser (23) and is used to obtain the initial flow field image at the outlet of the explosion wave simulation device (1).

3. The measuring device for the initial flow field at the outlet of an explosion wave simulation device according to claim 2, characterized in that: It also includes a tracer particle dissemination system; The tracer particle dispersing system is used to uniformly disperse tracer particles into the interior of the explosion wave simulation device.

4. A method for measuring the initial flow field at the outlet of an explosion wave simulation device, employing the measuring device for the initial flow field at the outlet of an explosion wave simulation device as described in claim 1, characterized in that, Includes the following steps: Step 1: Set the delay time in the synchro (4) or particle image velocimetry system (2). ; and seed tracer particles into the explosion wave simulation device (1); Step 2: Run the explosion wave simulation device (1). The shock wave propagates to pressure sensor 1 (31) and pressure sensor 2 (32). Pressure sensor 1 (31) and pressure sensor 2 (32) respectively collect the pressure discontinuity signal upstream of the outlet of the explosion wave simulation device (1) and send it to the oscilloscope (5). Step 3: The oscilloscope (5) records the pressure discontinuity signal and sends a trigger signal to the synchronizer (4); Step 4, Synchronizer (4) according to the trigger signal and delay time A start signal is sent to the particle image velocimetry system (2); the particle image velocimetry system (2) is started according to the start signal, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device (1); Alternatively, the synchronizing machine (4) sends a start signal to the particle image velocimetry system (2) based on the received trigger signal; the particle image velocimetry system (2) then uses the start signal and a delay time to initiate the signal. Start up to obtain the initial flow field image at the outlet of the explosion wave simulation device (1).

5. The method for measuring the initial flow field at the outlet of an explosion wave simulation device according to claim 4, characterized in that: The delay time Δτ mentioned in step 1 is the time difference between the time when pressure sensor #1 (31) receives the intermittent pressure signal and the start time of the particle image velocimetry system (2). The delay time Δτ is calculated by the following formula: ； In the formula, The time it takes for pressure sensor #1 (31) and pressure sensor #2 (32) to receive intermittent pressure signals. The distance between pressure sensor #1 (31) and pressure sensor #2 (32) is... The distance between pressure sensor #1 (31) and the outlet of the explosion wave simulation device (1) is... To determine the width of the observation area for tracer particles, The velocity of the tracer particles after the shock wave. This is the inherent delay time of the particle image velocimetry system.

6. The method for measuring the initial flow field at the outlet of an explosion wave simulation device according to claim 4 or 5, characterized in that: The particle image velocimetry system (2) includes a synchronization controller (21), a CCD camera (22), and a laser (23). In step 1, when the delay time When set within the particle image velocimetry system (2), it is specifically set within the synchronization controller (21); The particle image velocimetry system (2) described in step 4, based on the start signal and delay time... The startup process is as follows: the synchronous controller (21) determines the startup signal and the delay time based on the startup signal. The CCD camera (22) and laser (23) are started to work, thereby acquiring the initial flow field image at the outlet of the explosion wave simulation device (1).

7. The method for measuring the initial flow field at the outlet of an explosion wave simulation device according to claim 4, characterized in that, Step 1 includes the following: The explosion wave simulation device (1) is run. The shock wave propagates to pressure sensor 1 (31) and pressure sensor 2 (32). Pressure sensor 1 (31) and pressure sensor 2 (32) respectively collect the pressure discontinuity signal upstream of the outlet of the explosion wave simulation device (1) and send it to the oscilloscope (5). The oscilloscope (5) records the pressure discontinuity signal; the delay time is calculated based on the pressure discontinuity signal recorded by the oscilloscope (5). .

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