Development Of Piv Measurement System For Servo Valve Nozzle Jet And Flow Field Analysis

Nozzle is a key component of double-nozzle apron servo valve. The testing and matching of its processing qualit y is a key factor which affects the whole property deeply. Current ly in the production processes of servo valve the character of different ial pressure and flow is used to test the qualit y of process and provide some evidence for its matching. However, some nozzle which is qualified after the testing by character of different ial pressure and flow cannot be properly used in the whole servo valve. So that a more correct test ing method is needed. PIV(particle image velocimetry) is advanced technology for flo w measurement, which is used to measure the velocit y of the flow instant ly and noncontact, with a high correction and resolution. The experiment on nozzle by PIV technology can analyze the qualit y of nozzle in the angle of flow. In this paper the research on the PIV measurement system for the flow from nozzle in servo valve is made. The main works are as follows.Analysis of the state of flow from nozzle, principle and component of PIV measurement system is made. According to the feature of PIV technology, the experimental platform of nozzle is founded and constant oil source, nozzle jig are designed.Analysis of scattering and following character of tracer particles is made and some factors are pointed out. Some common tracer particle used in liquid flow are picked to make some quantitat ive calculat ion on its following character. Finally an ideal part icle is chosen to perform as the tracer part icle in nozzle flow.The software system for analysis of PIV flow field is developed based on GUI plat form in Mat lab. Two kind of cross correlat ion algorithm are picked to prove the software by PIV image in vortex field based on Fast Fo urier Transformation(FFT) and iterat ion mult igrid method. The distribution of velocit y vector in vortex field is made to prove the correct ion of the software system.The PIV measurement system is developed for nozzle flow field and some experiment of PIV measurement is performed by this system. The image of part icle in nozzle flow field is obtained and converted into distribut ion of velocit y vector by analysis. Some analysis on the field is made according to the distribut ion of velocity in instantaneous field.