Numerical study on flow and heat transfer mechanism of corrugated channel in plate heat exchanger

In this paper, the Realizable k-ε turbulence model is used to study the flow and heat transfer mechanism of a corrugated channel in plate heat exchanger. Considering various Reynolds number (Re) in turbulence regions, the variation of the averaged characteristic number on wall surface (Nu̅ and f̅) and the local characteristic number along the wall surfaces (Nux and fx) are investigated. In addition, the averaged and local distribution of internal flow and heat transfer parameters at various transverse profiles are analyzed. The results show that Nu̅ for the concave wall is larger than convex wall when Re<7860, while presents an adverse trend when Re>7860. However, f̅ on the convex wall is always larger than that on the concave wall. For the convex wall, Nux reach two peak values where near the exit is greater than the entrance. For the concave wall, Nux exist a peak value located near the entrance and a trough value located near the exit, respectively. As for fx, an instant increasing occurs near the exit of the convex wall, while appears near the entrance of the concave wall. Investigating the flow and heat transfer parameters at the five profiles, the higher velocity gradient, temperature gradient and TKE level is concentrated on the upstream of corrugation channel. A backflow is generated near the concave wall resulting in the occurrence of small velocity peak value and thickening the thermal boundary layer, however, the turbulence kinetic energy increases obviously in this region.