The Numerical Simulation and Experimental Investigation on the Heat-transferring Behavior of Sinusoidal Corrugated Tube

摘要

Heat transfer characteristics in a sinusoidal corrugated tube for developed laminar flow of water were investigated with finite elemental method in the present study. The simulation work was carried out for a Reynolds number at 200 ～ 1200. The results were presented in the form of velocity profiles, isothermal lines and the local Nusselt numbers at the length of one cycle. For a particular geometry, flow separates as fluid moves downstream into the diverging portion and reattaches on the converging portion, core of the separation bubble shifts downstream with the increase of Reynolds number, local Nusselt number distribution shows rise and fall in each cycle and this tendency decreases with the increase of axial distance and circulation number, heat transfer rate increases at converging parts and decreases at the diverging parts, maximum heat-transfer rate occurs near the reattachment point. With the help of heat-transfer experiments on water-vapor, the heat transferring properties of sinusoidal corrugated tube were studied and compared to those of straight tubes obtained by other authors. It is found that heat-transfer coefficients increase with the Reynolds numbers and that the sinusoidal corrugated tubes can transfer heat more effectively than the straight tubes do. At the same Reynolds number, the heat-transfer coefficients of sinusoidal corrugated tubes are about 3 times as much as that of straight tubes. Sinusoidal tubes can be widely used as effective heat-transfer enhancing components. With treating experimental data by regression, some dimensionless thermal formulas were obtained.