| To enhance turbine inlet temperature can obtain a higher output power. Therefore, the inlet temperature is always beyond the temperature limited of blade material in high-performance gas turbine. In order to ensure turbine blade can work as steadily and long time as possible, it require to adopt cooling techniques. Based on the modern advanced manufacturing technology, the study and improvement of turbine blade cooling structure is the core content of advanced cooling technique, and also is the guarantee that turbine blade can work in safety. For this reason, the research of cooling structure of the turbine blade trailing edge cutback is very significant.In this article, the author has constructed the cooling structure on the turbine blade trailing edge cutback, then set up a corresponding physical model and three-dimensional mathematical model. The finite volume method was used to simulate the cooling effectiveness which the cooling structure has caused, and to solved by the commercial software FLUENT 6.3. The numerical simulation results were compare to the experimental results in the references, and to testify the reliability of the model.The effect of various slot inner angle, rib structure and ribless structure, and flow parameters on the film cooling characteristics of trailing edge cutback were studied, respectively. In the end, the main research conclusion is summarized. Different from the other parts on the blade, the pressure side and suction side of trailing edge cutback are all hot end. Due to its special features of the flow field, two different define methods were used to measure the film cooling characteristics of trailing edge cutback. One is film cooling effectiveness and it base on the adiabatic wall temperature, the other is cooling effect and it base on the actual wall temperature. The cooling effect not merely reflect the gas film insulating effect, but also reflect the influence of heat transfer cause by the suction side, so it has good visual effect for engineering design.How the flow parameters affect the film cooling effectiveness of trailing edge cutback were studied. In the range of 1.5×104~1.6×105for cooling air Reynolds number, the film cooling effectiveness at the downstream of slot centerline was not changed obvious, and it increase at the downstream of rib centerline. The increase of Reynolds number can improve the cooling effect at the downstream of slot centerline, and the cooling effect at the downstream of rib centerline first increase and then decrease with the increase of Reynolds number. At the blowing ratio of 0.4~1.6, the increase of blowing ratio can enhance the film cooling effectiveness at the downstream of slot centerline, but can reduce the film cooling effectiveness at the downstream of rib centerline. It was also found that the increase of blowing ratio was good to the cooling effect of trailing edge cutback.Through the studies of the film cooling characteristics of trailing edge cutback at different slot inner angle, the increase of the slot inner angle can help improve the film cooling effectiveness, and the cooling effect is reduce with increase of the slot inner angle. In the operating condition that main flow Reynolds number is 3.0×105 and blowing ratio is 1.0, when slot inner angle goes from 0° to 10°, the film cooling effectiveness raises by 9.2%, and the cooling effect reduces by 0.85%. It had better select a smaller slot inner angle in practical engineering design.By comparing the cooling characteristics of the rib structure and the ribless structure reveals that, the velocity field and temperature field are in good synergy as the trailing edge cutback was ribless. So overall, the film cooling effectiveness and cooling effect of the ribless structure all above the rib structure, and the cooling characteristics of the ribless structure is particularly significant in the situation of high blowing ratio. |
PDF Full Text Request