Numerical modeling and experimental verification of flow and heat transfer over serrated fins at low Reynolds number

The objectives of this paper are to establish a numerical modeling method incorporated with few experiments by which the performance of fins with new configuration in plate-fin heat exchangers (PFHE) can be obtained and to investigate the pressure drop and heat transfer characteristics over serrated fins in PFHE at low Reynolds number in detail. Firstly, a variety of performance tests of PFHE were carried out with a constant air flow rate and six different oil flow rates. The Reynolds number ranged from 10 to 200 at the oil side. The Colburn factor j and friction factor f have been calculated from the experimental data. Secondly, the 3D heat transfer and pressure drop of PFHE were analyzed numerically by solving governing equations through two steps of increasing complexity. The first step was a simple model built to obtain the temperatures of separating walls. In this way, the overall heat performances were evaluated. The next step was a small scare with a high detail in the geometry description of the serrated fins at the oil side. The oil velocity and temperature distributions are shown in this step. Also presented and discussed in a detail description of local and average heat transfer characteristics of the serrated fins. The experimental results show good agreement with the corresponding numerical predictions. Hence, the numerical analysis procedure proposed in this paper can be used to predict the performance of new type fins.