A phase-based method for measuring local convective heat transfer coefficients

Abstract

Existing experimental heat transfer coefficient measurement techniques rely on the amplitude of the wall temperature, making the coefficients sensitive to noise and limited in spatial resolution. This paper presents a novel measurement technique that uses the phase-shift between wall and fluid temperatures to measure convective heat transfer coefficients. Here the phase-based method is derived theoretically, analysed numerically and validated experimentally with comparison to an existing transient technique. It is shown that using phase-shift rather than amplitude reduces a heat transfer coefficient measurement's sensitivity to noise by a factor of 10-50, reducing the power requirements for an experiment and enabling high spatial resolution measurements.