Inverse conduction and advection in a flat channel with transient external thermal excitation and observation

The transient profiles of temperature and normal heat flux inside a flat minichannel heated by a surface heat source are constructed from temperature measurement over its external heated face. It uses analytical expressions of the corresponding transfer functions which are calculated using Laplace and Fourier integral transforms. Firstly, this estimation technique is verified on synthetic outputs of a finite elements code (COMSOL). Then it is implemented on an experimental minifluidic bench with electrical heating and temperature measurement by thermocouples and infrared thermography, for a low Péclet number of the flow. The presented results show that the heat source can be recovered at any time, as well as the internal normal heat flux and temperature distributions, including the bulk temperature of the liquid flow.