Numerical simulation of hydrodynamics and heat exchange in a multibond part of the in-line heat exchanger

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

In this paper a process of heat and momentum transfer in the in-line cross flow heat exchanger is investigated on the base of numerical solution of Navier-Stokes equations and energy conservation equation. Obtaining numerical solutions for apparatus of this type has a number of difficulties related primarily to the construction of orthogonal difference grid. Therefore, the vast number of papers is related to the analysis of fluid flow and heat transfer around a cylindrical tube or its symmetric part rather than the entire tube bank. The present work deals with the investigation of heat and momentum transfer for the entire tube bank of heat exchanger. The numerical method used to solve the problem is based on the difference grid which is orthogonal in the entire region. The method consists in sharing a general Cartesian coordinate system and a local cylindrical coordinate system near each of the cylindrical channel. An exchange of the information between the coordinate systems is carried out in the region of low velocity and temperature gradients. It allows, on the one hand, to obtain a strict orthogonality on the surface of cylindrical channels and, on the other hand, to use a smaller spatial step in the field of large velocity and temperature gradients at the same time. The results are discussed in terms of dependences of Nusselt number on Reynolds number.