Computational Fluid Dynamics of a Corrugated Plate-and-Frame Heat Exchanger Used for Ocean Thermal-Energy Conversion

Abstract

Computational fluid dynamics (CFD) simulations were employed in this paper to analyze the dynamic flow patterns within extremely thin slit spaces of two corrugated heat exchanger (HEx) plates. The entire plates are 1.0 m long and wide and 6.5 mm high, and the top and bottom parts consist of six unit plates of the same size (1.0 m long and 16.7 cm wide). A digital geometry of the assembled HEx was prepared as a stereolithography (STL) file (exported from AutoCAD), having excessive geometrical complexity. In this work, a numerical algorithm to reconstruct the STL file is developed, which converts a complex STL file consisting of skew triangles to one having a simple grid structure and an even size-distribution of surface triangles. The whole STL file is split into 36 square pieces (SPs), and each SP is meshed individually using NETGEN, and these meshes are merged as one for OpenFOAM-based CFD simulations. Finally, the flow and pressure profiles are obtained in the low Reynolds number region. The current CFD method with the split-and-merge scheme will be continuously used for the design and optimization for ocean thermal energy conversion technology in the future.