FVM-BEM method based on the Green's function theory for the heat transfer problem in buried co-axial exchanger

Abstract

This Note presents the study of transient flow under forced convection in buried coaxial exchanger. The wall temperature as well as the wall heat flux and the heat transfer coefficient are unknown. A hybrid model consisting of a finite element method at the boundary (BEM) for the heat transfer problem on the boundary and a finite volume method (FVM) to solve the laminar flow inside solves this problem. The development of the BEM method is based on the Green's function theory. This conjugate method allows one to have fast results and to foresee the thermal behaviour of the exchanger. The heat transfer coefficients are investigated. The results are compared to those obtained using the commercial CFD package Fluent.

Study of the Heat Transfer of a Two-Tubular Exchanger with a Hemispherical End Buried

“…This part of the work is based on a study carried out by Mnassri [1]. The ground is supposed homogeneous and isotropic solid medium and its thermal characteristics are considered stable and independent of the temperature.…”

“…In addition, the heat transfer coefficient (fluid-wall) is also unknown. In this context, the solution of the problem of heat transfer of a laminar flow in a buried coaxial exchanger, where both wall temperature and wall heat flux are unknown, is based on the study of Mnassri [1], which was validated by an experimental study of Desmos [2], which allowed us to propose a correct correlation for the transfer coefficient h(z, t).…”

The employment of an earth-to-air heat exchanger as pre-treating unit of an air conditioning system for energy saving: A comparison among different worldwide climatic zones

“…better results with larger lengths and smaller diameters and air velocities). In 2010 Mnasri et al [33] introduced a 3-D model of a buried coaxial earth-to-air heat exchanger solved through a hybrid model: the finite element method was applied for the heat transfer problem, whereas the finite volume method was considered for the laminar flow evaluation. This method is called FVM (Finite Volume Method)-BEM (Boundary finite Element Method) and it allows to get faster results even despite of the complexity of the model due to its 3-D nature.…”

Study on Calculation Models of Earth-Air Heat Exchanger Systems

“…Mnasri et al [64] presented the study of transient flow under forced convection in buried coaxial exchanger. The wall temperature and the wall heat flux and the heat transfer coefficient were unknown.…”