NUMERICAL ANALYSIS OF UNSTEADY FLOW AND HEAT TRANSFER AROUND BODIES BY MAKING USE OF A COMPOUND GRID SYSTEM

摘要

This study has built up a numerical scheme of using a compound grid system around solid bodies for the purpose of predicting the heat transfer characteristics of actual finned tube heat exchangers. The scheme was validated by comparing the present numerical results with the experimental ones by Eckert (1952) and was confirmed to be quite effective to simulate the complicated cases such as in-line cylinder arrays, offset cylinder arrays as well as inclined fin arrays which are basic units of finned tube heat exchangers. As the secondary results, it was found that, for in-line cylinder arrays, the streamwise pitch of the cylinders is an important parameter of affecting the instability of the wake flow, and for offset cylinder arrays, the small cylinder row pitch slightly increases heat transfer but obviously leads to large pressure loss.