Rotating Effect On Heat Transfer In Cooling Passage

Turbine blades cooling is of great significance to the life of turbine blades and the efficiency.The main concern of this article is the heat transfer and flow structure in cooling channels under rotating conditions.We carried out numerical calculation of one-channel passages and multichannel passages.The calculation uses one-channel passage with three different structure: a smooth channel,a channel with V ribs and a V rib-dimple hybrid channel.For the multi-passage channels,we uses smooth channels and channels with 45 degree ribs and V ribs.Calculations are performed with Re=25000 and Ro= 0,0.02,0.05 and 0.12.The AKN k-ε model is used for straight channel.Results show that the channel with V rib-dimple hybrid structure can effectively increase the heat transfer by1.89 times times compared with the smooth channel.It has also the advantage of smaller friction factor when the rotating number increase comparing to the ribbed channel.In the multi-pass calculation,RNG k-ε model can correctly reflect the heat transfer and flow characteristics in the channel under the rotating conditions.With Re=25000,Ro=0.02 or 0.05,the heat transfer has an average error from 0.84% to16% and local error 23% maximum.Results show that the rotation force,the channel structure and the turn region have different effects on the flow structure.With 45 degree ribs or V ribs leading and trailing surfaces can increase the heat transfer by 2 to 2.5 times.Compared with 45 degree ribs,V-ribbed channel is more affected by rotation.