开孔折流板流动阻力特性

为了开发研制新型高效换热设备,针对新提出的一种开孔折流板强化传热方式,对流动和传热状况进行了实验研究。设计和建立了一套流动阻力特性试验装置,对流体流经交错布置多个开孔折流板的矩形通道时的阻力特性进行了测试。通过所引入的参数f/f0比较了折流板开孔与不开孔情况下阻力系数的变化特点。实验结果发现:折流板开孔后的阻力系数变化趋势基本相同;对于开孔密度分别为0.42%、1.41%和2.51%的折流板,在一定的Re数范围内其阻力系数将大于未开孔折流板。其余折流板的f/f0均小于1,且开孔密度越大,阻力系数减小的程度越高。Re数等于3000左右f/f0出现极大值。综合比较传热实验结果发现,设置开孔折流板是一种有效的传热强化措施。

Flow friction characteristics of the holed-baffles

In order to develop the high-efficiency heat exchanger,a new kind of heat transfer enhancement of the holed baffles was studied experimentally.A set-up for test of fluid flow friction characteristic was designed and built,which was used to measure the flow parameters for the rectangular channel with the staggered holed-baffles.By the new introduced parameter f/f0,the flow friction feature for holed and non-holed baffles can be analyzed.It shows that the friction variation trends are similar to the test holed-baffles.For the baffles with the hole density equaling to 0.42%,1.41% and 2.51% respectively,their friction factor is greater than that of non-holed situation under a certain range of Reynolds number;for the others baffles,f/f0 is always less than 1,or the friction factor is lower than that of the non-holed baffles,and the greater the hole density is,the smaller the reduced extent of flow friction factor will be.The maximum value of f/f0 exists when the Reynolds number is about 3 000.Considering the heat transfer effect,it is certain that setting holed-baffles is an efficient heat transfer enhancement measures.