A method to measure heat flux in convection using Gardon gauge

Abstract

Heat flux measurements are widely used in thermal environment analyses. The Gardon gauge is an excellent heat flux sensor with a wide measurement range and long lifespan in harsh environments. However, the Gardon gauge is usually calibrated for radiation heat transfer and is not good for convective heat transfer. This paper introduces a method to measure heat flux for convective heat transfer using the Gardon gauge by relating the measurement sensitivity for convection to that for radiation. The heat flux and convective heat-transfer coefficient can then be simultaneously determined by the standard thermo-electromotive voltage output of the Gardon gauge. The method was demonstrated for convective heat-transfer coefficient ranging from 200 to 3000W/(m2K). The analysis illustrates that the measurement sensitivity for convection decreases with increasing convective heat-transfer coefficient. A correction is necessary especially for higher convective heat-transfer coefficient. The corrected convective heat-transfer coefficients and heat fluxes agree well with the actual values. The relative uncertainty in heat flux is within 0.64%. The method not only greatly improves the measurement accuracy of the Gardon gauge for convection applications, but also provides a reference for evaluating convective heat transfer coefficients in convection environments.