Rotary fluid testing platform and method for rotary table

Abstract

The invention relates to the technical field of fluid mechanics experimental equipment, discloses a rotary fluid test platform and method for a rotary table, and aims to solve the problems of incapability of synchronously measuring a velocity field and a concentration field, difficulty in multi-section measurement, insufficient platform stability and optical distortion interference in the prior art. The platform comprises a rotating system, a fluid mixing system, a fluid testing system and a control and data processing system, the fluid testing system integrates PIV and PLIF technologies, multiple sections are irradiated through beam splitting laser, multiple cameras synchronously collect signals, the fluid mixing system adopts a refractive index matching solution to eliminate wall surface refraction, and the rotating system has an inclination angle adjusting function. According to the invention, multi-field synchronous measurement and wide-area multi-section test are realized, the measurement precision and stability are improved, and the device is suitable for accurate measurement of parameters such as speed and concentration under various rotating fluid working conditions, and is suitable for rotating fluid research in the fields of aerospace and the like.

Description

Technical Field

[0001] This invention relates to the field of fluid mechanics experimental equipment technology, specifically to a rotating fluid testing platform and method for a turntable, which is particularly suitable for the synchronous measurement of velocity, concentration, temperature, and other properties of the flow and mixing characteristics within a rotating cylinder. Background Technology

[0002] Turntables are important experimental equipment in the field of fundamental research in fluid mechanics. They can be used to test and analyze the flow characteristics of rotating fluids and the fluid-structure interaction between rotating fluids and solids, and have broad application prospects in aerospace and mechanical manufacturing.

[0003] In the study of rotating cylindrical flow, accurately acquiring the velocity, concentration, and temperature field distributions is crucial for revealing the fluid mixing mechanism. However, existing online testing techniques for the relevant physical fields of rotating flow have several shortcomings: First, there is a lack of simultaneous measurement methods for velocity and concentration fields, making it difficult to achieve coordinated analysis of multiple physical fields and comprehensively understand the flow field characteristics; second, in non-invasive measurements, limitations in device structure prevent the simultaneous acquisition of flow field information across a wide optical domain, making it difficult to meet the information acquisition needs of multi-section and multi-angle fluid domains under multi-parameter conditions; third, the experimental platform lacks stability, and factors such as vibration easily affect measurement accuracy, and existing studies often ignore this influencing factor, leading to reduced data reliability; fourth, the optical system is susceptible to refraction from the cylindrical wall, causing flow field imaging distortion and directly affecting data accuracy.

[0004] To address the shortcomings of the existing technologies, there is an urgent need for a rotating fluid testing platform and method that integrates multi-parameter control, multi-field synchronous measurement, and high-precision optical correction, in order to fill the gaps in the existing technologies and meet the high-precision testing requirements of rotating fluid research. Summary of the Invention

[0005] (a) Technical problems to be solved The present invention aims to solve the problems existing in the current rotating fluid testing, such as the inability to simultaneously measure the velocity field and concentration field, the difficulty of multi-section measurement, and optical distortion interference, so as to achieve accurate characterization of the flow characteristics of rotating fluids.

[0006] (II) Technical Solution To achieve the above objectives, this invention provides a rotating fluid testing platform and method for a turntable. Its core idea is to integrate a rotating system, a fluid mixing system, a fluid testing system, and a control and data processing system, combining PIV (Particle Image Velocimetry) and PLIF (Plane Laser-Induced Fluorescence) testing technologies, along with refractive index matching design and a multi-camera synchronous acquisition structure, to achieve multi-field synchronous, multi-section coverage, high-precision, distortion-free rotating fluid testing.

[0007] 1. Technical Solution The rotary fluid testing platform includes a rotation system, a fluid mixing system, a fluid testing system, and a control and data processing system. These systems work together to perform parameter control, signal acquisition, and data processing of the rotating fluid. Figure 1 As shown.

[0008] The rotating system includes a turntable platform 27, a rotating shaft 9, and turntable control software. It supports the entire system and provides rotation and tilt adjustment for the liquid-filled cylinder 11. The rotating shaft is vertically mounted at the end of the turntable shaft, and a high-precision servo motor provides rotational power to the shaft. Simultaneously, it allows for tilt adjustment of the liquid-filled cylinder to meet testing requirements under different nutation angle conditions. The turntable control software is installed on the control computer 26, precisely controlling motion parameters such as the shaft's speed and rotation mode. The turntable employs a dynamic balance counterweight design and vibration isolation measures to ensure stable platform operation.

[0009] The fluid mixing system includes a liquid-filled cylinder 11, a rotating water liner 10, and a working fluid. Both the liquid-filled cylinder 11 and the rotating water liner 10 are made of transparent material. The rotating water liner 10 is filled with a refractive index matching solution (such as an aqueous NaI solution), and the water liner 10 remains stationary relative to the fluid testing system. Tracer particles and fluorescent dyes are added to the working fluid inside the liquid-filled cylinder 11 to provide signal sources for PIV and PLIF tests, respectively. The lower end of the liquid-filled cylinder 11 is fitted with a countersunk hole in the support of the water liner 10. The water liner 10 is fixed to the turntable surface, ensuring that the rotating shaft 9 is coaxial with the water liner 10. The liquid level of the refractive index matching solution inside the water liner 10 is higher than the upper edge of the cylinder 11 to eliminate liquid surface refraction and ensure that there is no bubble interference on the observation surface.

[0010] The fluid testing system includes a laser generation module, an optical adjustment module, a signal synchronization module, and an image acquisition module. The laser generation module includes a laser 1, a beam splitter 3, and Powell prisms 4 and 7. The laser output from laser 1 is split into two beams by reflector 2 and beam splitter 3, which are then converted into planar lasers by Powell prisms 4 and 7, respectively. These planar lasers are then guided by reflectors 5, 6, and 8 and incident perpendicularly onto the cross-section and longitudinal section of the cylinder 11. The image acquisition module includes multiple CMOS cameras 14, 17, 21, and 24. Cameras 14 and 21 are used for PIV testing, equipped with narrowband filters 13 and 20 and polarizers 12 and 19 that allow only the original laser light to pass through. Cameras 17 and 24 are used for PLIF testing, equipped with high-pass filters 16 and 23 and polarizers 15 and 22 that allow only the excitation of fluorescence to pass through. A beam splitter cube 18 is used to split the light signal from the cylinder's cross-section into two equal beams, which then enter cameras 21 and 24 respectively. The signal synchronization module includes a signal synchronizer 25, which is used to synchronously control the laser 1 and cameras 14, 17, 21, and 24.

[0011] The control and data processing system includes a computer 26 and data processing software. The control computer is connected to the turntable control software, signal synchronizer 25, and CMOS cameras 14, 17, 21, and 24, respectively, to realize parameter setting, start-up control, and data acquisition for the entire experimental platform. The data processing software analyzes and processes the acquired image information to obtain the velocity field and concentration field distribution data of the flow field.

[0012] 2. Test Method The rotating fluid testing method based on the above platform includes the following steps: S1 Preparation and filling of working medium: Prepare the test working medium in the liquid filling cylinder, add the tracer particles and fluorescent dye in the preset proportion to the working medium; fill the working medium inside the liquid filling cylinder 11 and close the top cover; rotate the water liner 10 to fill the refractive index matching solution and vent the air to ensure that the liquid level is higher than the upper edge of the liquid filling cylinder.

[0013] S2 Platform Setup and Parameter Settings: Install cylinder 11 on the support of water liner 10 and adjust the tilt angle of cylinder 11; set the motion parameters of rotating shaft 9.

[0014] S3 Optics and Image Adjustment: Adjust the laser output, convert it into a planar laser through a beam splitter and Powell prism, and then guide it through a reflector so that the laser is perpendicularly incident on the cross-section and longitudinal section of the liquid-filled cylinder; align cameras 14 and 17 with the shooting area, and cameras 21 and 24 with the corresponding faces of the beam splitter cube; set the PIV / PLIF shooting parameters according to the test requirements, and check the installation compatibility of the filters and polarizers.

[0015] S4 Data Acquisition and Processing: The turntable and fluid testing system are started simultaneously, triggering the laser to emit laser light and the camera to capture images; the camera acquires scattered light images (PIV test) and excited fluorescence images (PLIF test) from two cross sections respectively, obtaining 4 sets of image information; the computer receives the image data captured by the camera and processes it according to the preset algorithm to obtain the velocity field and concentration field distribution results.

[0016] (III) Beneficial Effects 1. Multi-field synchronous measurement: Integrating PIV and PLIF technologies, it enables the simultaneous acquisition of velocity and concentration fields of two cross sections, solving the problem that existing technologies cannot perform coordinated analysis; 2. Wide-area multi-section testing: By changing the planar laser and multi-camera layout, it supports multi-section measurements such as cross-sections and longitudinal profiles, expanding the range of flow field information acquisition; 3. High precision and stability: High-precision servo motors, dynamic balance counterweight design, and vibration isolation measures are adopted to ensure stable platform operation; 4. Optical distortion elimination: By using specific materials for refractive index matching (such as NaI aqueous solution) and water liner design, the refractive interference of the cylindrical wall surface is effectively eliminated, improving imaging accuracy. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the overall structure of the experimental platform. In the figure: 1 laser, 2 mirror, 3 beam splitter, 4 Powell prism, 5 mirror, 6 mirror, 7 Powell prism, 8 mirror, 9 rotating shaft, 10 rotating water liner, 11 liquid-filled cylinder, 12 polarizer, 13 narrowband filter, 14 CMOS camera, 15 polarizer, 16 high-pass filter, 17 CMOS camera, 18 beam splitter cube, 19 polarizer, 20 narrowband filter, 21 CMOS camera, 22 polarizer, 23 high-pass filter, 24 CMOS camera, 25 signal synchronizer, 26 computer, 27 turntable. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below with reference to Figure 1, so that those skilled in the art can accurately implement the present invention.

[0019] S1 Working fluid preparation and filling S11 Determine the type and concentration of the refractive index matching solution, and the ratio of tracer particles to fluorescent dye added to the working fluid.

[0020] S12 Prepare the test working fluid according to the preset formula, stir evenly, then add tracer particles and fluorescent dye, and continue stirring until completely dispersed. Slowly inject the working fluid into the filling cylinder, avoiding the generation of air bubbles. After filling, tighten the top cover and check the sealing performance. Inject the refractive index matching solution into the rotating water liner, venting air while injecting, ensuring that the liquid level is 2-5mm above the upper edge of the filling cylinder to eliminate interference from liquid surface refraction.

[0021] S2 Platform Setup and Parameter Settings S21 sets the motion parameters (rotation speed, nutation angle, etc.) of the liquid-filled cylinder through the turntable control software according to the experimental research objectives.

[0022] S22 Install the liquid-filled cylinder into the countersunk hole of the water-lined support, ensuring it is coaxial with the rotating shaft; confirm again that the tilt angle adjustment meets the experimental requirements.

[0023] S3 Optics and Image Conditioning S31 Debugging the laser optical path: Ensure that the planar laser formed after passing through the reflector, beam splitter, and Powell prism accurately covers the target test section; S32 camera positioning calibration: Align four CMOS cameras with the cross-section and longitudinal section respectively, adjust the focal length and shooting angle to ensure image clarity; verify that the narrowband filter of the PIV camera and the high-pass filter and polarizer of the PLIF camera are working properly.

[0024] S4 Data Acquisition and Processing S41 starts the turntable, and synchronizer 25 synchronously triggers laser 1 and cameras 14, 17, 21, 24 and other devices; The laser output from S42 laser 1 is split into two beams by reflector 2 and beam splitter 3. The beams are converted into planar lasers by Powell prisms 4 and 7, respectively. After being guided by reflectors 5 and 8, the laser beams are perpendicularly incident on the cross-section and longitudinal section of cylinder 11. Four CMOS cameras 14, 17, 21, and 24 are aligned with the two cross-sections. CMOS cameras 14 and 21 receive the scattered light processed by polarizers 12 and 19 and narrowband filters 13 and 20. CMOS cameras 17 and 24 receive the excitation fluorescence processed by polarizers 15 and 22 and high-pass filters 16 and 23.

[0025] The S43 computer 26 acquires and processes images taken by cameras 14, 17, 21, and 24 to obtain experimental results.

[0026] In this embodiment, the velocity and concentration field distributions of the fluid inside a rotating cylinder can be successfully obtained using the aforementioned platform and method. Through the specific implementation described above, accurate measurement of the velocity and concentration fields of the fluid inside a rotating cylinder can be achieved. The entire experimental process is stable and reliable, and the data is accurate and comprehensive, meeting the experimental requirements for studying the flow characteristics of rotating fluids. The scope of protection of this invention is not limited to the specific implementation described above. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A rotary fluid testing platform for a turntable, characterized in that, It includes a rotation system, a fluid mixing system, a fluid testing system, and a control and data processing system. The rotation system provides rotation and tilt adjustment for the liquid-filled cylinder, the fluid mixing system provides a suitable working fluid and a non-refractive interference environment for fluid testing, the fluid testing system realizes multi-section multi-physics field signal acquisition, and the control and data processing system completes parameter control and data processing. The rotary system includes a turntable surface, a rotating shaft, and turntable control software. The rotating shaft is vertically mounted at the end of the turntable. The fluid mixing system includes a liquid-filled cylinder, a rotating water liner, and a working fluid. The liquid-filled cylinder and the rotating water liner are made of transparent materials. The rotating water liner is filled with a refractive index-matching solution and remains stationary relative to the fluid testing system. The working fluid in the liquid-filled cylinder contains tracer particles and fluorescent dyes. The fluid testing system includes a laser generation module, an optical adjustment module, a signal synchronization module, and an image acquisition module. The laser output from the laser generation module is processed to form a planar laser. The image acquisition module includes four CMOS cameras. The signal synchronization module synchronously controls the laser and the cameras. The laser generating module includes a continuous laser, which is split into two laser beams by a broadband dielectric film beam splitter. The two laser beams are converted into planar laser beams by a Powell prism and respectively irradiate the cross section and longitudinal section of the liquid-filled cylinder. The control and data processing system includes a control computer and data processing software. The control computer is connected to the turntable control software, signal synchronizer, and camera. The data processing software processes the image information acquired by the camera.

2. The rotary fluid testing platform for a turntable according to claim 1, characterized in that, Of the four CMOS cameras, two are PIV test cameras and two are PLIF cameras. The PIV test cameras are equipped with narrowband filters and polarizers, while the PLIF cameras are equipped with high-pass filters and polarizers. The narrowband filters allow only the original laser light to pass through, while the high-pass filters allow only the excitation of fluorescence to pass through.

3. A rotating fluid testing method based on the platform described in claim 1 or 2, characterized in that, Includes the following steps: S1 Working fluid filling: The inside of the filling cylinder is filled with working fluid, and the top cover is modified; the water liner is rotated to fill the refractive index matching solution and the air is vented; S2 Platform Setup and Parameter Settings: Install the cylinder onto the water-lined support and adjust the cylinder's tilt angle; set the motion parameters of the rotating shaft; S3 Optics and Image Adjustment: Adjust the cross-section and longitudinal section of the liquid-filled cylinder by the planar laser, align the camera with the shooting area, and set the PIV / PLIF shooting parameters; S4 Data Acquisition and Processing: Simultaneously start the turntable and fluid testing system to acquire four image information from two cross-sections of the flow field.

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