Simultaneous Thermochromic Liquid Crystal Calibration and Calculation of Heat Transfer Coefficients

Abstract

The use of thermochromic liquid crystals (TLCs) to indicate surface temperature in transient experiments designed to measure heat transfer coefficients requires careful calibration of the crystals. The calibration can be affected by lighting and viewing angles, light source spectral characteristics, surface preparation, and application procedure of the TLCs. A method is proposed whereby the calibration of the TLCs and calculation of heat transfer coefficients are conducted simultaneously using inverse techniques for the case of a suddenly heated semi-infinite wall. The calibration inherently accounts for the problems typically associated with the use of liquid crystals and results from simulated experiments indicate accuracy to within five percent is possible.