房水流动粒子图像测速测试中跟随性示踪粒子选择的实验研究

Selection of tracing particles with optimal following performance for particle image velocimetry test of aqueous humor flow

目的在房水流动粒子图像测速(particle image velocimetry,PIV)测试中,选择最佳跟随性示踪粒子是展示真实流场的必要前提。本文探讨眼球房水慢流PIV测试中不同粒子的跟随性并选择最佳显影效果的示踪粒子。方法依据几何相似性原理,设计并加工5倍于真实人眼大小的眼球模型;分别选择10μm空心玻璃珠,以及1μm、3μm、7μm和20~50μm粒径荧光粒子作为示踪粒子,运用PIV系统在眼球模型上进行流场测试,比较粒子的空间分布规律探讨粒子跟随性问题,确定可用于房水流场测试的最佳示踪粒子。结果荧光粒子的粒径越大,沉淀的速度越快,则沉淀量越多。1μm的荧光粒子跟随性好,但显影效果不佳。3μm荧光粒子随着测量时间的增加,沉淀最不明显,跟随性和显影效果最佳。结论示踪粒子直径对其在眼球房水流动中的跟随性和显影效果具有显著影响。基于当前的PIV设备,3μm荧光粒子是房水流场测试最佳的示踪粒子。本研究可为采用PIV技术进行体外房水流场测量提供一定的实验基础。

Objective In the particle image velocimetry(PIV)test on aqueous humor flow,the selection of optimal tracing particles with optimal following performance is a necessary prerequisite to show the real flow field.This paper investigates the following performance of different tracing particles and selects tracing particle with optimal exposure effect in the PIV test of low-speed aqueous humor flow field in eyes.Methods A five-fold human eyeball model was designed and fabricated.The 10μm hollow glass beads,1μm,3μm,7μm and 20~50μm fluorescent particles,were selected as the tracing particles for the measurement of PIV system on the eyeball model.The spatial distributions of the different particles were compared to explore the problem of particle following performance so as to determine the optimal tracing particle for the aqueous humor flow test.Results The larger the particle size,the faster the precipitation rate and the more the precipitation amount.The following performance of 1μm fluorescent particle was good while its exposure effect not fine.The precipitation of 3μm fluorescent particle was the least obvious,and its following performance and exposure effect were the best with the increase of measurement time in the current PIV system.Conclusions The diameter of tracing particle has significant influence on its following performance and exposure effect in aqueous humor flow.The 3μm fluorescent particle is the best tracing particle for the measurement of aqueous humor flow field based on the present PIV system.This study provides certain experimental basis for the aqueous humor flow in vivo by using PIV technology.