EVALUATION OF ANALOG AND NUMERICAL TECHNIQUES FOR UNSTEADY HEAT TRANSFER MEASUREMENT WITH THIN FILM GAUGES IN TRANSIENT FACILITIES.

The importance of frequency response considerations in the use of thin film gauges for unsteady heat transfer measurements in transient facilities has been considered and methods for evaluating it have been proposed. A departure frequency response function has been introduced and illustrated by an existing analog circuit. A Fresnel integral temperature which possesses the essential features of the film temperature in transient facilities has been introduced and used to evaluate two numerical algorithms. Finally criteria have been proposed for the use of finite difference algorithms for the calculation of the unsteady heat flux from a sampled temperature signal.