Ultra low pressure drop, high thermal performance evaporator: Experiments and analyses
Résumé
In this paper, a particular evaporator architecture based on the implementation of local capillary pumping is investigated through extensive experimental campaigns. The main goal of this study is to demonstrate the possibility of a decorrelation between the heat transfer coefficient and the induced pressure drop. To this end, a dedicated experimental system has been set up. It consists in an evaporator designed according to this architecture and an associated test bench allowing the characterization of both the thermal and hydraulic performances of the prototype. The experimental results allowed to describe the general operation of the device while heat transfer coefficients of the order of for pressure drops lower than are reported. A comprehensive experimental analysis of the evaporator functioning, including an investigation of the heat and mass flux repartition within the device is then proposed. Finally, the influence of various experimental parameters is detailed, showing that the device is capable of functioning in a wide range of operating conditions while maintaining a stable thermal performance thanks to self-adaptation of the flow vaporized within the capillary structure. Concurrently to this experimental approach, an analytical model of the hydraulic equilibrium associated to the evaporator assembly is used to quantify the mechanisms that cause the distinct operating modes observed as well as proposing an optimization of the operating range.