Heat Transfer Model Analysis of a Hybrid Porous Compact Heat Exchanger

Abstract

Development of energy-saturated technical systems is characterized by constructive compactness, for example, radio electronic devices, mobile power plants, ground control systems for space complexes, etc. There is an intensively cooling problem of heat-generating surfaces. The development of new types of porous heat exchangers and the prediction of their operating modes is a crucial task when creating stable heat removal systems. A model of a hybrid recuperative porous heat exchanger is developed, which differs from the already known models with the availability of an additional circuit for cooling external walls. The thermal and hydraulic characteristics in porous heat exchangers are tested using the example of planar geometry under conditions of intense heat generation from compact surfaces. Within the framework of the phenomenological theory, a mathematical model of convective heat transfer in a porous heat-exchange element for the conjugate Darcy-Brinkman-Forchheimer equations and Schumann equations is proposed for thermal boundary conditions of the first and second order. An exact analytical solution of the hydrodynamic and thermal problems is obtained. The influence of porosity, permeability, Darcy and Reynolds numbers on the thermal and hydraulic conditions in a porous compact heat exchanger was evaluated. A comparative analysis showed the efficiency of a double-circuit cooling system with a porous regenerative heat exchanger. The rational ranges of hydraulic and thermal characteristics of the developed porous compact heat exchangers are determined taking into account the presence of the second circuit, critical operating modes are tested. The variant of realization of a double-circuit cooling system is proposed.