周期性环肋通道内的流动和换热

Numerical simulation on flow and heat transfer in annular channels with interlaced ribs

用非稳态数学模型对包含入口段的带肋环形通道内的流动和换热进行了数值模拟．在肋片参数Sp／D=0．1875、Sp／D=1．125，雷诺数在400-800范围内，流动和换热都出现了自维持振荡特性，且入口段后，各几何周期的速度场、无因次过余温度场基本相同，随时间的变化规律也基本相同．肋片高度增加，平均努塞尔数和摩擦阻力系数增加．肋片间距增大，对摩擦阻力系数影响较小，对努塞尔数影响较大．雷诺数增大，努塞尔数增大，阻力系数减小．

The flow and heat transfer in annular channels with ribs were simulated using unsteadystate model. The results reveal that the flow and heat transfer show the self-sustained oscillation characteristics when Sp/D equals 0. 187 5 or 1. 125 and Re ranges from 400 to 800. After several modules in entrance the velocity field and the dimensionless temperature field of each module remain almost unchanged and their changing regulation with respect to the time are also the same. It is also found that the average value of Nu and friction factor f will be larger when the height of the ribs is increased. The distance between the fins has little influence on f but large effect on Nu. When the Reynolds number Re is increased Nu will increase also, however, f will decrease.