THE EFFECTS OF GAP SPACING RATIO ON FLOW STRUCTURE AND HEAT TRANSFER CHARACTERISTIC FOR THE V-ORIFICE IN THE SQUARE CHANNEL HEAT EXCHANGER

摘要

The variations of flow and heat transfer in the square channel heat exchanger inserted with various parameters of V-orifice are investigated numerically. The influences of flow directions (V-Downstream and V-Upstream), gap spacing ratios (g/H or GR = 0, 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30) and blockage ratios (b/H or BR = 0.05, 0.10, 0.15, 0.25 and 0.30) on flow topology and heat transfer behavior are reported. The laminar flow regime with the Reynolds number in the range 100 – 2000 is considered. The numerical results are presented in terms of flow and heat transfer structure in the heat exchanger channel. The thermal performance assessments in the square channel with V-orifice are also concluded. As the numerical results, the gap between the V-orifice and channel walls changes the flow and heat transfer mechanisms in the channel. The gap can reduce the friction loss in the channel and also helps to increase the turbulence of the flow. The optimum gap spacing ratio may help to increase the thermal performance of the square channel heat exchanger.