基于菲涅尔透镜的改进型纹影成像系统

AN IMPROVED SCHLIEREN IMAGING SYSTEM BASED ON FRESNEL LENS

纹影法可将气体的密度变化可视化,故常用于对透明气体介质的观察,但也存在大口径纹影设备价格昂贵的弊端。本文提出了一种低成本的大口径纹影仪搭建方法,使用透射成像光路,用菲涅尔透镜代替传统纹影仪中的玻璃凸透镜进行装置的搭建。文章通过实验验证了该方案的可行性,计算了实验中纹影系统的灵敏度,并针对菲涅尔透镜的成像问题提出了相应解决方案。改进后的系统具有口径大、搭建简单、价格低廉的优势,可用于中小型实验室对于变密度气体的观察。

The density change of gas can be visualized by the schlieren,which is often used to observe the transparent gas medium.However,large aperture schlieren systems are usually quite expensive.In this paper,a low cost method for constructing large aperture schlieren system is proposed.The device is constructed by using the transmission imaging optical path and using the Fresnel lens instead of convex glass lens used in traditional schlieren system.This paper verifies the feasibility of the scheme through experiments,calculates the sensitivity of schlieren system in experiments,and puts forward corresponding solutions to the imaging problem of Fresnel lens.With the advantages of large caliber,simple structure and low cost,the improved system can be used for the observation of variable density gases in small and medium-sized laboratories.