用脉冲激光全息术测量喷雾场中粒子的分布和运动速度

本文叙述了用脉冲激光全息术测量喷雾场中粒子的分布和运动速度的原理，阐明了同轴全息和离轴全息在测量雾场的应用范围，重点讨论了离轴全息。测量光学系统是４Ｆ系统，它可以测量粒子浓度大的雾场中大于５μｍ的粒子分布和运动速度。在平行光场区段，可进行不同装置、不同景深的喷雾研究，使每个粒子具有相同的放大倍数，它给再现、数据处理、粒子大小的标定都有很大的好处。文中还分析了在底片上形成干涉的各种情况；粒子直径ｄ，远场数Ｎ和从底片到粒子的距离Ｚ的关系。给出脉冲间隔为５μｓ；１０μｓ粗度为±０．１μｓ时不同直径粒子的分布和运动速度在电视屏幕上显示出来的照片。在上述实验结果的基础上讨论了粒子的识别，噪音的消除等问题。

Measuring Particle distribution and in Spray Field by Pulse Laser Holography

The principle of measuring particle distribution and moving speed in spray field by pulse laser holography is related.The area where the coaxial and off-axial holography are applied to measure the spray field is given,centring on off-axial holography. The measuring optical system is 4F system,which can measure the particle′s distribution and moving speed in a high density spray field of particles larger than 5μm,In the parallel optieal field,the spray research can be done with different instruments and in different depth of field,making each particle get the same magnifying power.It will be of benefit to the reproduction,data processing and the calibration of particle size. The interference patterns formed on the plate and the relationship among the diameter of the particled, far-field number N and the distance from the plate to the particle Z are analysed.Photos of the distribution and moving speed of different size particle,which displayed on TV screen,are shown when the pulse interval is 5μs or 10μs with the error of±0.1μs.On the basis of results mentioned above,the particle′s identification and the elimination of noise are discussed.