Numerical studies of the effects of shaped holes on cooling effectiveness of flat plate film with conical shrink entrance and conical diffuser exit

The numerical simulation was used to study the film cooling effectiveness of plate with jet holes by increasing the heat transfer of wall of hole and enlarging the cooled area of plate in the side of hot gas stream.By studying different shape of jet holes,a new shaped hole(conical shrink entrance and conical diffuser exit shaped hole) was proposed.The computational results show that,the conical shrink entrance of the new shaped hole can efficiently enhance the convection heat transfer of wall of hole,and the conical diffuser exit of the new shaped hole can efficiently enlarge the cooled area of plate in the side of hot gas stream.If comparing with the conical diffuser shaped hole,it is found that,when the shrinkage hole is used,the film cooling effectiveness of plate is enhanced with low blowing ratio,and the film cooling effectiveness is inferior with high blowing ratio.However,when compared with the cylindrical hole,when the new shaped hole is used,the film cooling effectiveness of plate can be improved in any case.