عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
TL56032
انگلیسی
Özet Squealer Ti̇p Türbi̇n Kanat Ucunda Fi̇lm Soğutma Deli̇kleri̇ni̇n Pozi̇syon Opti̇mi̇zasyonu
[Thesis]
Yıldız, Faruk
Alpman, Emre
Marmara Universitesi (Turkey)
2019
57 p.
Master's
Marmara Universitesi (Turkey)
2019
Efficiency of gas turbine engines increases with increasing temperature and this situation directs scientists to design gas turbine engines that can works under higher temperatures. Therefore, cooling of turbine blades that works under high thermal loads becomes more important. There are many scientific studies that try to reduce heat transfer on tip surface, which is one of the critical areas on turbine blades, by using film cooling. Scientific studies show that positions of film cooling holes are important for reducing heat transfer on surface however they deal with specific positions. In this study, position optimization of film cooling holes is studied with 2 objectives which are heat transfer on tip surface and aerodynamic performance of blade. A blade with conventional squealer tip is used and its cascade model is numerically analyzed by using OpenFOAM. 5 film cooling holes are used, and they are equally spaced on axial chord length of the blade. Positions of 4 film cooling holes in y-axis of computational domain are used as input parameters for optimization and fifth hole which is closed to trailing edge is fixed on a position. By using the utilities in OpenFOAM, positions of film cooling holes are changed without changing generated mesh for all numerical analyzes. Blowing ratio is selected as 1 for film cooling. Three-dimensional, steady, incompressible form of Reynolds Averaged Navier Stokes (RANS) equations are used for numerical analyzes and Shear Stress Transport (SST) k-ω is used as turbulence model. For optimization process, Artificial Neural Network (ANN) is used to reduce number of analyzes and Non-Dominated Sorting Genetic Algorithm NSGA-II is selected as an evolutionary optimization algorithm. Total pressure loss coefficient and heat transfer on tip surface of the blade is reduced with using film cooling. Especially the effect of film cooling on cavity surface is higher than other regions. Heat transfer on tip surface is further reduced with position optimization of film cooling holes however the aerodynamic loss of the blade is reduced by film cooling but is not affected by optimization. On the other hand, film cooling does not effectively protect the leading edge of tip surface because of flow direction and a region with high wall heat flux remains. However, wall heat flux is reduced almost all other regions that has high wall heat flux values with film cooling and 9.8% reduction in heat transfer on cavity surface with respect to worst case is obtained with position optimization.
Mechanical engineering
Yıldız, Faruk
Alpman, Emre
Marmara Universitesi (Turkey)
مطالعه متن کتاب p
[Thesis]
276903
a
Y
