Estimation of the heat transferred to a fluid in a minichannel by an inverse technique
Abstract
This paper deals with reconstruction of the temperature and normal heat flux transient profiles inside a flat minichannel from external temperature measurement over its external heated face. It uses an analytical model which is written using Laplace and Fourier integral transforms whose output is verified through comparison with a finite elements code. Estimation of the Fourier harmonics of the external experimental temperature profile at different times is regularized through Truncated Singular Value Decomposition. A similar technique is used in time for a regularized deconvolution of each harmonics of this temperature. This inverse technique has been 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, as well as the internal normal heat flux and temperature distributions, including the bulk temperature of the liquid flow at any time. Possible applications concern the transient characterization and heat management of thermal systems, such as flat plate solar collectors or heat exchangers with low to medium temperature level, for fatal heat recovery.