Investigations On Internal Flow And Heat Tranfer Characteristics Of Jet Array Impingement In Turbine Case

As the main bearing bodies of turbine stator, the inner air flow and heat transfer charasteristics of case affect the distribution of temperature and deformation observably. This article presents study of two types of turboshaft case, including internal flow structure, flow loss, tempureture distribution of case, impinging heat transfer inside the case and the cooling efficiency of gas side of the turbine shroud and this can provide foundamental data to optimization design and engineering development.Firstly, 3D CFD was applied to resarch the cooling type of model A, and the resutls of CFD show the flow characteristic of array impinging jet and flow allocation in disign status of the turbine case and the flow loss and heat transfer of different flow path is discussed deeply. Then the internal flow and heat transfer characteristic of different status is discussed.The results shows that the main loss of pressure occurs at the orifice and the maximum pressure drop is 519 MPa. Because of the multideck structure,there is vortex in the cavity.The flow and heat transfer characteristic is different with the change of the jet location,the case structure and orifice can affect the development of the impinging jet and so as to the local and everage heat transfer.The highest temperature point is on first shroud gas side and the lowest temperature point is on the cool side of second shroud.Basd on the CFD results,experimental reaserch is applied,which is focused on the affect of jet Rej,H/d,P/d to Nu.The Nu increases with the increase of jet Re and the orifice strengthen the local heat transfer.The heat transfer of array jet/flim cooling structure is best when P/d is 2.875,but H/d has little affect to the heat tranfer.At last,CFD is applied of cooling type B,including high pressure and low pressure.Flow allocation,flow loss,heat transfer characteristic and integrated cooling effect of impinging/film cooling type in disign status is obtained.Result shows that the allocation of flow stay the same when operating status changed.The impinging jet can increase the local heat transfer and is affected by the orifice and case structure.The cooling efficient is highest at the outer of film orifice and decrease when it is away from the ofifice.Cooling effiecient in different status decreases when blowing rate increases.