Study On Heat Transfer Enhancement In Steam Cooling Blade

Developing the advanced turbine blade cooling technology is one of the key technologies of the modern advanced gas turbine. The steam cooling blade has a lot of merit compared with the tradition air cooling blade: on the one hand, steam is a more effective cooling medium than air, which allows the vane stands higher gas temperature with the same cooling flow rate as air cooled vanes; on the other hand, it can eliminate or reduce the need to drawn cooling air from compressor, which is favorable to improve the thermal efficiency of the gas turbine and combined cycle.In this article, the software Pro/E and ANSYS ICEM was used to make computational model and computational grid of the turbine blade, then the software Fluent was used to simulate the inner flow in turbine. During computing standard k-εcouple equation turbulence model and SIMPLE arithmetic are applied. The concrete job as follows:1. Numerical simulation of the single hole of film cooling on the plane and the arrangement of the pin fin. The Adiabatic Effectiveness is observed with the different blowing rate, and the result is that the film cooling efficiency is the best when the blowing rate M=0.5. When the Reynolds number is enhanced, two arrangement of the pin fin's heat transfer is enhanced, and the change of pin fin in-order is more obvious.2. Numerical simulation of the film-pin fin composition cooling blade. On the basis of the result above and one of the turbine guide vane, the film-pin fin composition cooling blade is designed , The film cooling holes' location, diameter and the pin fin' arrangement are optimal designed to be the better cooling effect. With the enhanced of the air cooling flow-rate, the vane surface temperature is reduced, a nd the distributing of the Adiabatic Effectiveness on different film cooling holes is not homogeneous.3. Numerical simulation of the impinging-rib composition steam cooling blade. By analyzed the result, the impinging holes location, angle and diameter are improved to achieve the best cooling effect when the least cooling steam was used. With the enhanced of the steam cooling flow-rate, the vane surface temperature is reduced, but the trend is more and more small.Enhancing or diminishing the angle of attack of the gas, the cooling effect of the film-pin fin composition cooling blade is changed worse than before, but the impinging-rib composition steam cooling blade was almost invariable; when the steam is used as the cooling substance to take place of air, the surface temperature of the impinging-rib composition steam cooling blade is reduced about 70K; at the leading edge,nearby the film cooling holes wall and the trailing edge of the film-pin fin composition cooling blade, the surface temperature is reduce about 100K, but the wall covered with the film is reduced about 30K; the cooling effect of two blades are compared, and the impinging-rib composition steam cooling blade is better.