Numerical and experimental analysis of mixed convection in exchangers

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.

Fields of vector speed have been measured by the method of laser visualisation (PIV) in the case of a vertical heat exchanger in co current in mixed convection. The reversal zones have been given prominence for different numbers of Grashof and Reynolds. Where the internal and external flows are weak(in the region of 51/h) and the differences of internal and external temperature are in the region of 20°C ,we see reversal zones appear in the two places simultaneously. These results show the importance of studying the thermal exchange of a heat exchanger in its totality and call into question the traditional methods of proportionality of a heat exchanger.