An improved data reduction method for transient liquid crystal thermography on film cooling measurements

This study proposes an improved data reduction method for the applications of transient liquid crystal thermography on film cooling effectiveness meas urements. On the evaluations of film cooling effectiveness and heat transfe r coefficient, an "equivalent step temperature"(EST) is proposed to replace the Duhamel's superposition principle which is conventionally used to acco unt for the actual temperature rises in both free-stream and injection flow s rather than the ideal step temperature changes. For obtaining both values at over thousands of measured locations, the current data reduction method can effectively reduce the calculation time as compared with the conventio nal Duhamel's superposition method, but adds only negligible errors. (C) 20 01 Elsevier Science Ltd. All rights reserved.