Numerical and Experimental Investigation of Aerodynamic Performance for a Straight Turbine Cascade With a Novel Partial Shroud

Abstract

A comparative experimental and numerical analysis is carried out to assess the aerodynamic performance of a novel partial shroud in a straight turbine cascade. This partial shroud is designed as a combination of winglet and shroud. A plain tip is employed as a baseline case. A pure winglet tip is also studied for comparison. Both experiments and predictions demonstrate that this novel partial shroud configuration has aerodynamic advantages over the pure winglet arrangement. Predicted results show that, relative to the baseline blade with a plain tip, using the partial shroud can lead to a reduction of 20.89% in the mass-averaged total pressure coefficient on the upper half-span of a plane downstream of the cascade trailing edge and 16.53% in the tip leakage mass flow rate, whereas the pure winglet only decreases these two performance parameters by 11.36% and 1.32%, respectively. The flow physics is explored in detail to explain these results via topological analyses. The use of this new partial shroud significantly affects the topological structures and total pressure loss coefficients on various axial cross sections, particularly at the rear part of the blade passage. The partial shroud not only weakens the tip leakage vortex (TLV) but also reduces the strength of passage vortex near the casing (PVC) endwall. Furthermore, three partial shrouds with width-to-pitch ratios of 3%, 5%, and 7% are considered. With an increase in the width of the winglet part, improvements in aerodynamics and the tip leakage mass flow rate are limited.

Loss analysis of the shrouded radial-inflow turbine for compressed air energy storage

“…Some researchers argue that the secondary vortex cores are the origin of secondary losses. [37][38][39] The high f EL appears near the vortex cores while the n EG is near the edge of vortices, as shown in Figure 9. These results might be related to the contributions of viscous effects.…”

Numerical simulations and optimizations for turbine-related configurations

“…The authors [22] have designed a winglet-shroud (WS) tip to control the tip leakage flow for a linear turbine cascade, and conducted experiments and BCFD simulations to evaluate the aerodynamic performance of the WS tip with tip injections. Figure 4 illustrates the experimental WS tip geometry with five circular jet holes.…”

A study of angle parametric optimization of the composite honeycomb on turbine blade tip

“…A variety of tip leakage flow control methods have been proposed, and flow control is divided into active flow control and passive flow control based on a study by Lord et al 4 The two control methods are distinguished by the presence or absence of external energy. For example, tip winglets, 5,6 ribs, 7 squealers, 8,9 and casing contouring 10 are considered passive control methods. Tip injection 11,12 and plasma actuators 13 are classified as active control methods.…”