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

The uncertainty analysis of temperature and velocity measured by thermo-sensitive liquid crystal particles suspended in a fluid flow was studied by using artificial colour images. These colour images were generated from the numerical simulation data of thermal convection combined with the experimental relationship between the temperature and the colour of the liquid crystals. The results indicate that the accuracy of the temperature measurement depends on the technique used for transformation from colour to temperature and the best accuracy is obtained by the use of the hue-saturation-intensity 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 images. Further improvement in the accuracy of velocity measurement was attempted by adding colourless tracer particles in the visualization.