An uncertainty analysis of temperature and velocity measured by a liquid crystal visualization technique

The uncertainty analysis of temperature and velocity measured by thermo-sen sitive liquid crystal particles suspended in a fluid flow was studied by us ing artificial colour images. These colour images were generated from the n umerical simulation data of thermal convection combined with the experiment al relationship between the temperature and the colour of the liquid crysta ls. The results indicate that the accuracy of the temperature measurement d epends on the technique used for transformation from colour to temperature and the best accuracy is obtained by the use of the hue-saturation-intensit y calibration technique. The accuracy of velocity measurement was optimized by selecting suitable combinations of PIV parameters, such as the size of interrogation window, size of search window and pixel displacement of the i mages. Further improvement in the accuracy of velocity measurement was atte mpted by adding colourless tracer particles in the visualization.