【摘要】 为研究气体流动及温度均匀度对微小尺度精密光学测量的影响,设计了混合对流实验并利用自准直仪测量通过流场的光束偏移。实验表明:当雷诺数恒定时,随格拉晓夫数的增大,光路上温度均匀性变差,水平和竖直方向上光束偏移量均增大。对于同一格拉晓夫数,随入口流速的增大,竖直方向温度梯度及光束偏移都增大,水平方向上情况则相反。可知气体流动和温度均匀性是影响光束偏移的其中两点原因,控制合理的流速及温度均匀度有利于提高非均匀流场中光学测量精度。更多还原

【Abstract】 To investigate the effect of gas flow and temperature gradient on optical measuring precision of microscopic scale,a thermal cycling test of mixed convection was organized and a photoelectric autocollimator was used to measure the deflection of the optical beam passing through the flow field.The results of the experiment showed that as Grasholf number grows,the temperature uniformity on the optical light goes down while the optical deflection on both vertical and horizontal direction goes up.For a constant Grasholf number,as the inlet velocity increases,both temperature gradient and optical deflection on vertical direction grows,however,things on horizontal direction shows an inverse law of change.So it can be concluded that gas flow and temperature uniformity are two of the reasons which influence the optical deflection.A rational control of inlet velocity and temperature uniformity is incredible for the improvement of optical measuring precision in a nonuniform flow field.更多还原