A numerical study on flow and heat transfer analysis of various heat exchangers

Abstract

This paper describes numerical methodologies of the flow and heat transfer analysis in heat exchangers of various types. Heat exchangers considered in the present study include a louver fin radiator for a vehicle, a shell and tube heat exchanger for HVAC and plate heat exchangers with patterns of herringbone and of dimple used in waste heat recovery. For the analysis of the louver fin radiator, a 3-D Semi-microscopic Heat Exchange (SHE) method was used. SHE was characterized by conjugated heat transfer analysis for the domain which consists of water in a tube, tube wall, the region where passes through the louver fin and ambient air. It is shown that both the air flow in louver fin area and the water flow inside the cooling water passages are successfully predicted along with the heat transfer characteristics. A conjugate heat transfer analysis in a shell and tube heat exchanger was also performed. For the analysis of entire shell side of the heat exchanger, geometric features such as tubes, baffles, inlet and outlet were modeled in detail. It is shown from the analysis that a design modification for better flow distribution and thus for better performance can be proposed. Finally an analysis method for the conjugate heat transfer between hot flow–separating plate–cold flow of a plate heat exchanger was proposed. By using periodic boundary conditions for the repeating sections and appropriate inlet and outlet boundary conditions, the heat transfer in a plate heat exchanger with patterns of herringbone and of dimple was successfully analyzed. Comparisons of the present numerical results are in a good agreement with available experiment data.