Global pressure acquisition system and method for rotating model

Patent metadata

Field	Value
Publication number	US-12372423-B2
Application number	US-202318181567-A
Country	US
Kind code	B2
Filing date	Mar 10, 2023
Priority date	Oct 9, 2022
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

The disclosure discloses a global pressure acquisition system for a rotating model, including a CCD camera, a signal generator, a stroboscopic pulse LED light source, a photoelectric sensor, a preset counter, and a controller. The disclosure further discloses a global pressure acquisition method for a rotating model. The disclosure has the beneficial effects that, by using the non-contact measuring method disclosed by the present disclosure, a measured model and a flow field are not damaged, a submillimeter-level spatial resolution is achieved, it is ensured that the acquired PSP image of the rotating model is clear, and the signal to noise ratio of the image is increased.

First claim

What is claimed is:

1. A global pressure acquisition system for a rotating model, comprising a CCD camera, a signal generator, a stroboscopic pulse LED light source, a photoelectric sensor, a preset counter, and a controller, wherein the global pressure acquisition system is configured such that:
PSP is sprayed in a measured area of the rotating model, and a reflective patch is pasted in a non-measured area of the rotating model rotating at the same speed;
the photoelectric sensor is disposed to face the rotating model and is connected to an input end of the signal generator; when the rotating model rotates to any to-be-measured phase, a light spot emitted by the photoelectric sensor is irradiated on the reflective patch, and is received by the photoelectric sensor after being reflected, and a signal is sent to trigger a channel A and a channel B of the signal generator to send signals;
the CCD camera carries a lens, the lens is aligned with the rotating model and is capable of shooting a complete image of the rotating model, and a bandpass filter only allowing a light emitting waveband of the PSP to pass through is mounted in front of the lens to prevent ambient light and light emitted by the light source from entering a photosensitive chip of the CCD camera; the CCD camera is connected to a computer by a data connecting line, and the computer is used for controlling an exposure time of the CCD camera; after being acquired by the CCD camera, a light emitting signal of the PSP is photoelectrically converted and is sent to the computer by the data line to form a PSP image; and an external triggering interface of the CCD camera is connected to the channel A of the signal generator, the signal generator sends a signal to the CCD camera via the channel A to control initial exposure time of the CCD camera, and the exposure time of the CCD camera is controlled by the computer; and
the stroboscopic pulse LED light source is disposed to face the rotating model, and light emitted by the stroboscopic pulse LED light source is capable of covering a to-be-measured area; the stroboscopic pulse LED light source is connected to one end of a relay switch of the preset counter, and the other end of the relay switch of the preset counter is connected to the channel B of the signal generator; and the channel B of the signal generator sends a signal to control a single pulsed light emitting time and a light emitting frequency of the stroboscopic pulse LED light source.

2. A global pressure acquisition method for a rotating model, comprising the following steps:
step 1 , providing the respective components of the global pressure acquisition system for the rotating model according to claim 1 ;
step 2 , mounting the CCD camera and the stroboscopic pulse LED light source in a static state of the rotating model;
step 3 , setting the stroboscopic pulse LED light source to continuously emit light, shooting an image I 1 of the to-be-measured area in the static state by using the CCD camera in an automatic triggering manner, taking the image I 1 as a reference image, sending the image I 1 to the computer, and recording an exposure time T 1 of the CCD camera at the moment by the computer;
step 4 , turning on the photoelectric sensor, aligning the photoelectric sensor with the synchronously rotating non-measured area of the model, pasting the reflective patch to a model position where a light spot emitted by the photoelectric sensor reaches at the moment;
step 5 , turning off the photoelectric sensor, adjusting the stroboscopic pulse LED light source to a modulated external triggering mode, sending a signal by the channel B of the signal generator to control the light emission of the stroboscopic pulse LED light source, and adjusting the CCD camera to the external triggering mode;
step 6 , setting a signal pulse width t of the channel B of the signal generator, i.e., single light emitting time of the stroboscopic pulse LED light source, according to an experimental rotating speed n;
step 7 , setting the number N of times of light emission of the stroboscopic pulse LED light source, setting the preset number of the preset counter to be N, and setting that exposure time T 2 of the CCD camera is not shorter than the time during which the rotating model rotates for N circles;
step 8 , turning on the rotating model, enabling a rotating speed of the rotating model to reach a measured rotating speed n, after the rotating model rotates to a phase in a static reference state, sending a triggering signal to the signal generator by the photoelectric sensor to control the CCD camera to start to expose and control the signal generator to trigger the stroboscopic pulse LED light source to start to emit light at the same time;
step 9 , after blades of the rotating model rotate for N times, stopping the light emission of the stroboscopic pulse LED light source;
step 10 , after the exposure time of the CCD camera reaches T 2 , outputting an experimental image I 2 to the computer; and
step 11 , calculating a light intensity ratio of the two images, and calculating pressure distribution according to a light intensity-pressure calibration formula.

3. The global pressure acquisition method for the rotating model according to claim 2 , wherein in step 2 , when the CCD camera and the stroboscopic pulse LED light source are mounted, a position where the PSP is sprayed is adjusted so that the CCD camera is capable of shooting a complete area where the PSP is sprayed; and a measuring distance of the stroboscopic pulse LED light source is adjusted so that the emitted light is capable of covering the complete to-be-measured area.

4. The global pressure acquisition method for the rotating model according to claim 2 , wherein in step 7 , the number N of times of the light emission of the stroboscopic pulse LED light source satisfies N=T1/t, that is, a total light emitting time of the stroboscopic pulse LED light source in the experimental image is consistent with that of a static reference image.

5. The global pressure acquisition method for the rotating model according to claim 2 , wherein in step 11 , the light intensity-pressure calibration formula is expressed as:
I 2/ I 1= A+B×P 2/ P 1,
wherein P 1 is an ambient pressure of the rotating model in the static state, P 2 is a surface pressure of the rotating model in a motion state, and P 1 and P 2 are measured by a pressure sensor; and A and B are calibration coefficients which are constants.

6. The global pressure acquisition method for the rotating model according to claim 5 , wherein the calibration coefficients A and B are acquired by using the following method: placing a sample wafer sprayed with PSP in a pressure-adjustable cabin, adjusting a pressure in the cabin to P 1 , and acquiring a light emitting image Ic of the PSP at the moment by a camera; repeatedly adjusting the pressure P in the cabin, and capturing a corresponding light emitting image I by the camera; substituting repeatedly-acquired data into a calibration formula I/Ic=A+B×P/P1 to form binary linear equations with variables A and B; and calculating A and B by a least square method.

Assignees

• Univ Northwestern Polytechnical

Inventors

• Gao Limin
• Ge Ning
• Wang Lei
• Ouyang Bo
• Lei Xiangfu

Classifications

• G01L11/02

  by optical means · CPC title

• G01L1/24 Primary

  by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis {using infrared, visible light, ultraviolet} · CPC title

• G01M9/067 Primary

  visualisation · CPC title

• G01L1/247 Primary

  using distributed sensing elements, e.g. microcapsules (along a single optical fibre G01L1/242) · CPC title