Abstract
This study was carried out to investigate the loss mechanism of a blade with a harbor seal whisker structure on the trailing edge under different Mach numbers. The loss of high-pressure turbine blades with four different trailing edge geometries, including a prototype, an elliptical trailing edge (ETE), a sinusoidal trailing edge (STE), and a biomimetic trailing edge (BTE) at Mach numbers of 0.38–1.21 is studied. The delayed detached-eddy simulation method is used to predict the detailed flow of the four cascades. The result shows that, when the Mach number is less than 0.9, the BTE can effectively reduce the energy loss coefficient compared with the other three cases. As the Mach number increases, the three-dimensional characteristics of the wake behind the BTE weaken. The energy loss coefficient of the blade with the BTE is close to that of the blade with the ETE and STE when the Mach number is greater than 0.9. Besides this, by controlling the wake, the BTE can effectively suppress the dynamic movement of shock waves in the cascade at high Mach numbers.
Highlights
Due to the wide application of modern gas turbines, such as power generation, aviation, and in the oil and gas industries, gas turbines are designed to meet different working conditions
It is proved that the bionic trailing edge can suppress the Karman vortex and reduce wake loss significantly at an exit Mach number of 0.79 in (Luo et al, 2019), as mentioned above, different exit Mach numbers have a great influence on the form of trailing edge vortex for conventional blades, so the important purpose of this paper is to study the influence of the biomimetic trailing edge (BTE) on the wake vortex and the ability to control wake loss under different Mach number conditions (0.38–1.21), especially after the Mach number is greater than 1, and the influence of BTE on the shockwave system and related loss
In the subsonic region, the energy loss coefficient increases with the increase of exit isentropic Mach number and reaches the maximum at the Mach number about 0.97 and decreases until it reaches the minimum at the Mach number close to 1.1
Summary
Due to the wide application of modern gas turbines, such as power generation, aviation, and in the oil and gas industries, gas turbines are designed to meet different working conditions. Léonard et al (2010) compare the ability of Reynolds-averaged Navier–Stokes (RANS), unsteady RANS (URANS), and large eddy simulation (LES) methods to simulate a turbine blade at a high subsonic outlet Mach number. They show that the RANS method cannot depict the unsteady flow of the wake. Lin et al (2017b) use a DDES code with a low-dissipation numerical scheme to simulate the flow of a high-pressure turbine stage. They explain the length characteristics of the wake vortices and reveal the transportation of the vortices
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
