Particle image speed measuring device, method and system

Abstract

The invention discloses a particle image speed measuring device, method and system. The device comprises a laser unit for emitting the laser to a to-be-measured region; an acquisition unit for acquiring the particle image of the to-be-measured region; a control unit electrically connected with the laser unit and the acquisition unit to control the movement and / or state of the laser unit and the acquisition unit, wherein the laser unit emits at least two beams of laser, and the light emitting time sequence between the laser beams satisfies the incremental or decreasing relation; the acquisitionunit at least comprises two acquisition channels, and the acquisition time of each acquisition channel meets the incremental or decreasing relation, and corresponds to the light emitting time sequence of each beam in the laser unit in sequence. The device and the method overcome the contradiction that the light emitting frequency and the pulse energy of a single laser are difficult to improve atthe same time, the problem of high-speed photography is solved, and the resolution of the measurement system is greatly improved.

Description

technical field [0001] The application relates to a particle image velocity measurement device, method and system, belonging to the technical field of aerodynamic experiments. Background technique [0002] Particle Image Velocimetry (PIV) technology is a transient, multi-point, non-contact hydrodynamic velocity measurement method. Its biggest feature is that it breaks through the limitations of single-point velocity measurement technology. The velocity distribution information on a large number of spatial points is recorded, and further processing can obtain the distribution of flow field characteristic parameters such as vorticity, streamline and isokinetic line of the flow field, which has high measurement accuracy. In addition to scattering tracer particles to the flow field, all measuring devices do not enter the flow field, and have very little impact on the flow field. Therefore, it has become a widely accepted and popular fluid dynamics measurement technology. It has...

AI Technical Summary

Problems solved by technology

[0005] (1) It is difficult to increase the output frequency and pulse energy of the PIV laser at the same time, which limits the time resolution of the measurement system

Although the Nd:YAG laser pulse time used in the current PIV system is very short, generally less than 10 ns, in order to realize the velocity measurement, the laser needs to illuminate the flow field at least twice, and the pulse time interval is limited by the laser output power. Energy is a set of contradictions, and the pulse time interval is difficult to shorten

Coupled with the limited frame rate of high-speed cameras, the shortest time between two frames of common domestic high-speed cameras was only about 1 microsecond before, which also limits the time resolution of the PIV system to the order of 1 microsecond

[0006] (2) Limited by the acquisition speed of high-speed cameras, it is difficult to realize the PIV measurement method with more than two channels

If the time resolution of the PIV system exceeds the order of 1 microsecond, the recording speed of the camera is required to exceed 1MHz, and it can record multiple frames continuously. The current development level of high-speed cameras is still difficult to meet this demand

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