Study On Heat Transfer And Flow Characteristics Of Multi-Channel In Turbine Blade Using Swirl Flow

The development and manufacture of aero-engines marks the level of industrialization in a country,and the cooling effect of turbine blades is the key to the success of aero-engine development.Therefore,researching new enhanced heat transfer structures has always been a topic of concern to the academic community.Based on this,this paper applies swirl cooling to the internal cooling passage of the turbine blade.The swirling cooling has the advantages of high heat transfer strength,good thermal uniformity and stable flow structure,when compared with other cooling methods;The internal multi-channel can improve the uniformity of the flow and increase the heat exchange intensity,and the cooling performance is better in the actual rotating blade.In this paper,the flow and heat transfer of three processes in the ordinary transition channel and the swirl channel are studied experimentally and computationally.The results of transient liquid crystal experiments show that when the inlet Reynolds number is 40,000,the heat transfer capacity ratio of the second,and the third process of swirl channel is 3.0 times and 2.9 times comparing with the full development segment.At the same time,the swirl channel is accompanied with the greater pressure loss,the static pressure loss of the whole channel is 2.8 times that of the turning channel.As the Reynolds number increases,the pressure loss ratio increases.Observing the local heat transfer distribution obtained from the experiment,it was found that there is a low heat exchange zone at the inlet of the second process,where the swirl flow generates.At the same time,within the range of Re=20,000～80,000,CFD was used to study the change of Nu/Nu0 with the Reynolds number on the surface of the swirl channel.The calculation results show that the Nu/Nu0 increases first and then decreases with the increase of Reynolds number;It can be found that the swirling effect can effectively improve the uneven distribution of the wall surface velocity caused by the centrifugal force and increase the heat transfer uniformity.On the other hand,monitoring the velocity and static pressure distribution near the experimental point,it is found that using the total pressure as the pressure loss criterion should be better when comparing the momentum loss of different types of channels.