Development simultaneous of a simultaneous measurement system of temperature and concentration fields and effect of double-diffusive convection on crystallization

为了阐明热对流和溶质对流共存体系中产生双扩散对流的机理，对氦氖激光全息干涉法（HI）与氩激光诱导荧光（LIF）相结合的温度场和浓度场同步测量系统进行了基础研究。首先，将HI应用于双扩散对流，并从得到的干涉条纹中尝试计算局部浓度，根据干涉条纹与反射指数等高线一致的事实，以及温度和浓度对反射指数的影响。结果，利用干涉条纹和测量的局部温度确定了准稳态下给定时间的局部浓度。干涉条纹得到的浓度是合适的。由上述结果可知，当得到温度场时，可以预测浓度场。因此，为了开发获得温度场的技术，使用LIF进行了液相温度场的可视化。通过对荧光图像的三刺激值（RGB）分析，发现卷筒的亮度随温度的变化呈线性变化。利用这一关系，LIF图像的定量分析成为可能。对温度、浓度稳定的体系进行浓度场测量时，测量误差为±5%。

In order to illustrate the mechanism of double-diffusive convection generated in the system with which heat convection and solutal convection coexist, a basic study was performed to develop a simultaneous measurement system of temperature and concentration fields using He-Ne laser holographic interferometry (HI) in combination with Ar laser-induced fluorescence (LIF).First, HI was applied to the double-diffusive convection and calculation of local concentration was tried from the interference fringes obtained Following facts were employed that interference fringe agree with contour lines of reflective index, and that both temperature and concentration influence reflective index. As s result, local concentrations at given times in a quasi-steady state were determined using interference fringe and measured local temperatures. The concentration obtained from interference fringes was appropriate.From the above-mentioned result, when a temperature field is obtained, a concentration field can be predicted. Therefore, for the purpose of development of techniques obtaining the temperature field, the visualization of temperature field in a liquid phase using LIF was performed. Through the analysis of the tristimulus values (RGB) of the fluorescence image, it was found that the change in the brightness of reel is linear with temperature. The quantification of LIF images became possible by using this relation.When the concentration field was measured for the system with stable temperature and concentration, it was measurable with ±5% of error.