Numerical Investigation of Thermofluid Flow Characteristics With Phase Change Against High Heat Flux in Porous Media

Abstract

This study numerically evaluates thermofluid flow characteristics in porous medium by a newly developed “modified two-phase mixture model” applying Ergun’s law and a two-energy model instead of a one-energy model. In a single-phase flow case, thermal nonequilibrium between a solid phase and a fluid phase is observed in the area where imposed heat conducts from a heating wall and further convective heat transfer is more active. The degree of thermal nonequilibrium has a positive correlation with the increase in flow velocity and heat flux input. In the case of two-phase flow, the thermal nonequilibrium is remarkable in the two-phase region because the solid-phase temperature in this region is far beyond saturation temperature. A difference between these two models is obvious especially in the two-phase flow case, so that the numerical simulation with the modified two-phase mixture model is indispensable under the high heat flux conditions of over 1MW∕m2.

Cooling Effect of Water Injection on a High-Temperature Supersonic Jet

“…Based on this model, a complete mixture model was built by Bowen [15]. In 1980, Lee [16] derived detailed and complete vaporization equation and condensation equation, and combined them with the mixture model to simulate gas-liquid flow. Yamazaki [17] analyzed the effect factors about the diameter of liquid drop in gas-liquid by applying mixture model.…”

Simulation of liquid–vapour phase change process inside porous media using modified enthalpy formulation

“…(1) and (2) remain invariant for all versions of TPMM and the energy conservation equations (20) and (25) for the h-and the H-formulations, respectively, are remarkably similar to each other, they are solved in a similar manner as elaborately described by Alomar et al [27]. However, if r in the single phase regions are functions of T, Eq.…”

“…The equations governing the respective one-dimensional formulation have been obtained by integrating the multidimensional (axi-symmetric) conservation equations (1), (2), (20) and (25) over the evaporator cross-section 10 . For the H-formulation [12], the procedure has been elaborately presented by Alomar et al [27].…”

Transient two-phase flow and heat transfer with localized heating in porous media

“…(22) and (23) are the new scheme proposed by Voller and Swaminathan [27] who termed it the "modified" Kirchhoff method. The current work will adopt the same terminology for easy reference.…”

“…The effects of latent heat storage and the thickness of the porous layer on the heat transfer were investigated. Yuki et al [22] modified the two-phase mixture model to study high flow velocity in the porous media. Their results showed that the modified equations produced more realistic and reasonable results for the two-phase flow under high velocity and high heat flux.…”