Numerical investigation of the turbulent cross flow and heat transfer in a wall bounded tube bundle

Abstract

Tube bundles are usually used for heat transfer in heat exchangers. The walls bounding the tube bundles will influence the flow and heat transfer in the tube bundles. This becomes critical for the once through steam generators of gas cooled reactors due to it is very compact and sensitive. URANS simulation of the cross flow and heat transfer in a wall bounded inline tube bundle is presented in this paper. The numerical method was verified with experimental measurements. The local and average flow and heat transfer characteristics were analyzed. The flow has the intrinsic characteristics of unsteadiness as that in a free tube bundle. Bounding walls modify the flow and heat transfer significantly. Near wall flow passages have lower flow resistances due to the walls suppress wakes after the tubes. The fluid velocities in the near wall passages are larger and the temperatures are higher. The wall effects depress turbulence intensities of the flow in the near wall flow passages, so the heat transfer coefficients of the near wall tubes are 10% lower than those of the tubes in the middle of the bundle.