A numerical investigation of thermal-hydraulic characteristics in three dimensional plate and wavy fin-tube heat exchangers for laminar and transitional flow regimes

Abstract

The plate fin-and-tube heat exchangers are used in wide variety of industrial applications, particularly in the heating, air-conditioning and refrigeration industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. The current study is focused on two fin configurations, the plain plate-fin and the wavy-fin. These two fin configurations are numerically investigated in both staggered and in-lined tube layouts. The present investigation ranges from laminar flow regime into the sub-critical or transitional flow regime. The suitability of the eddy viscosity turbulence models for the flow representation in the transitional flow regime is discussed in this study. This study reveals that the flow distinction between plain and wavy fin has a profound influence on the heat transfer and flow friction performance of these configurations when compared on the basis of tube layouts. The obtained results also indicate that the number of tube rows plays an important part for the overall heat exchanger performance and an optimum choice for the number of tube rows must be made in order to achieve the critical balance between high heat transfer performance and low pressure drop.