压敏漆测压在低速射流撞击壁面的应用研究

压敏漆(pressure sensitive paint,PSP)测压是一种基于发光分子氧猝灭效应的测压技术,与传统测压方式相比具有成本小、空间分辨率高等特点.实验搭建了压敏漆测压硬件平台,开发了数据处理软件系统.利用驻点处的压强与灰度关系拟合了标定曲线,研究了低速射流撞击平板表面的压强分布特性,分析了喷管距离壁面高度和雷诺数的影响.结果表明,当喷管高度h/d6时,压强分布曲线的峰值压强和半宽度随喷管高度变化基本不变;当喷管高度h/d6时,随着高度的增大,峰值压强线性减小,半宽度线性增加.采用峰值压强和半宽度对不同喷管高度的压强分布曲线进行无量纲化,压强分布曲线呈现自相似特性.进一步研究表明,在实验雷诺数范围内,压强分布受雷诺数影响较小.

STUDY OF PRESSURE DISTRIBUTION OF A FIXED WALL UNDER LOW-SPEED JET IMPINGEMENT USING PRESSURE SENSITIVE PAINT

Pressure sensitive paint(PSP) is a pressure measurement technology based on oxygen quenching mechanism of luminescence.Compared with conventional techniques, PSP technique has lower cost and higher spatial resolution.In this work, the PSP technique platform is constructed.It consists of the hardware for measurement and the software for data processing.A novel calibration method for PSP is developed and validated, which is based on the relation between intensity and pressure at the stagnation point of the impinging wall.The influences of Reynolds numbers and impingement heights between the orifice and the wall on the pressure distribution are analyzed.When the ratio value of impingement heights h/d is smaller than 6, the pressure distribution remains the same at different heights.When the value of h/d is greater than 6, the peak pressure decreases while the half width increases linearly with the increase of the impingement height.Pressure distribution curves are self-similar at different impingement heights when they are normalized by the peak pressure and half width.Further study shows that the pressure distributions are rarely influenced by the Reynolds number at the same impingement height.