Numerical and Experimental Investigation of Enhancement of Turbulent Flow Heat Transfer in Tubes by Means of Truncated Hollow Cone Inserts

摘要

In this study, the incompressible turbulent flow in a circular channel with a series of conical hollow inserts, placed axisymmetrically, is investigated numerically and experimentally. In computations, FLUENT, a commercially available CFD code, is used. The inserts are installed in a diverging structure towards the incoming flow. The effect of the inserts geometry on the heat transfer at hte wall is evaluated for a range of Reynolds number between 3000 and 20000. It is demonstrated that a significant enhancement in heat transfer from the tube wall occurs in comparison with the conventional plain tube, and the level of the enhhancement depends on the flow rate, the type of the inserts and the installation possitions of the inserts. In order to see the flow fields, the velocity profiles are shown. Using the entropy minimization technique the optimum geometries and the installation distances were estimated. The results obtianed through the numerical simulation are compared with the experiemtnal ones and, a satisfactory agreement is found.