Elliptic Trailing Edge for a Turbine Blade: Aerodynamic and Aerothermal Effects

Abstract

Three-dimensional flow simulations through a turbine cascade are carried out for an exit isentropic Mach number of 0.79. The objective of the present study is to qualitatively and quantitatively clarify the effect of using an elliptic trailing edge (TE) instead of a circular one on the flow. Calculations are carried out using a parallel, turbulent, structured, singleblock code and the delayed detached eddy simulation is employed for turbulence. We maintain the TE thickness (minor axis) and modify the other axis (major axis). Time-averaged pressure and heat transfer coefficient distributions along the blade are presented with more attention paid to the TE region. The results show that increasing the major-to-minor axis ratio decreases both the heat transfer coefficient and loss. Therefore, designers can adjust this ratio according to application needs.

Characterization of base bleed effects on subsonic trailing edge flows

“…As also suggested by El Gendi et. al [18], Melzer and Pullan pointed out that the use of an elliptic trailing edge shape will both increase and equalize the base pressure, suppressing transonic vortex shedding for those conditions where straight or slightly rounded trailing edges would develop it. Luo et al [19] proposed a biomimetic spanwise trailing edge shape that was able to eliminate the shedding of von Kármán vortices, transforming them into small three-dimensional vortices that would quickly dissipate reducing the mixing losses.…”

Influence of the Trailing Edge Shape of Impeller Blades on Centrifugal Pumps with Unsteady Characteristics

“…Similarly, Huang et al [14] examined the entropy distribution and pressure pulsation within centrifugal pumps at different flow rates, considering turbulent dissipation rates and wall friction dissipation rates. Meanwhile, El-Gendi et al [15] used delayed detached eddy simulations to investigate the relationship between energy losses and the transformation of turbine machinery from a circular to an elliptical trailing edge with varying aspect ratios. Hoseinzade et al [16] optimized the local entropy integral and other objectives by altering the trailing edge angle of steam turbine blades, studying the impact of this angle on thermodynamic losses.…”

Numerical Study on the Biomimetic Trailing Edge of a Turbine Blade Under a Wide Range of Outlet Mach Numbers

“…However, Xu and Denton (Xu and Denton, 1988) point out that, although the introduction of coolant ejection can increase the base pressure, additional losses are introduced by the coolant ejection. On the other hand, elliptic trailing is found to be able to delay the separation of the boundary layer and reduce the loss caused by vortex shedding (El-Gendi et al, 2013). El-Gendi et al (2010) use the equidistant microtubes that connect the suction side and pressure side at the beginning of the trailing edge to control the wake.…”