PRINCIPLE OF FIELD COORDINATED ENHANCEMENT OF SINGLE PHASE THERMAL CONVECTION

Abstract

Unlike the existing techniques of heat transfer enhancement using extended surfaces and/or turbulence promoters etc., the present study starts from a revisit at the mechanism of convective heat transfer, and then, indicates that the heat transfer rate depends not only on the flow and temperature fields, but also on their coordination. Based on the analyses and numerical and experimental verification of a number of convection cases, we suggest a principle called the principle of field-coordinated enhancement of convection ----- the better the coordination between the flow and heat flow fields, the higher is the heat transfer rate of convection. This principle can lead to novel approaches for heat transfer enhancement, which can markedly enhance heat transfer, but have less additional increase in the flow resistance. The field coordination number, Fc, which is equal to the integral of the dot product of the dimensionless velocity and temperature gradient vectors over the domain studied, has been introduced to describe the coordination degree of the velocity field and temperature gradient field for thermal convection. Hence, The field coordination number can act as criteria to compare the heat transfer performance of different convection cases.