Numerical Study of Plate Fin Heat Exchanger for Cryogenic Applications

Abstract

Among different types of plate-fin heat exchangers, offset-strip fin heat exchangers are widely used for cryogenic applications. Though many correlations are available in literature for plate-fin heat exchangers, still there is a requirement to sort out more accurate correlation through parametric analysis. In view of this, the present study is focused on thermo-fluidic analysis involving numerical analysis of periodically sectioned 3-D geometry with 12 offset fins. The outcome of the numerical simulation is presented in the form of Nusselt number, overall efficiency, j factor, and f factor by considering temperature-dependent fluid properties for varying Prandtl number, thermal conductivity of solid, and fluid flow rate. Five different fin materials and nitrogen (at three different states) as the working fluid with Re in the range of 50 to 1000 have been considered in the numerical analysis. The results indicate that there are no significant variations in considered parameters concerning temperature difference ranges of 1K, 2K, and 3K. The f factor is independent of the thermal conductivity of fin material and the Prandtl number of working fluids. As thermal conductivity increases, the increment of j factor for working fluid with Pr > 1 is more rapid than Pr < 1. The decrement of the overall efficiency of working fluid with Pr < 1 is less compared to Pr > 1, as Reynolds number increases.