A combination application of tandem blade and endwall boundary layer suction in a highly loaded aspirated compressor outlet vane

Abstract

Aspirated compressor is a promising design concept to enhance the power density of the compression system; however, with regard to the rear stages of multistage aspirated compressor, the blade is fairly thin. Limited by the mechanical constraints, it seems impractical to implement the boundary layer suction on the blade suction surface. So the question arising is can we replace the blade suction surface with other feasible flow control methods without implementing extra device on the blade? To address this issue, a compound flow control method, composed of the endwall boundary layer suction and tandem blade, is proposed. The design philosophy is to utilize the EBLS to suppress the three-dimensional corner stall while to use the tandem blade to control the two-dimensional airfoil flow separation. The endwall boundary layer suction is barely implemented in the forward blade, whereas the corner flow in the rear blade is restrained by the flow through the gap between the forward and rear blades. The preliminary implement strategy of the compound flow control was presented and then applied in the design of a highly loaded aspirated compressor outlet vane. Three-dimensional numerical simulations were carried out to validate its effectiveness with different inlet boundary layer distributions. Both flow fields in the outlet vane and its loss characteristics were analyzed. The results show that, by applying the compound flow control, the outlet vane could not only achieve an aggressive loading without incurring large-scale separation at the design point but also have a considerable available incidence range. Due to the implement of the endwall boundary layer suction, the tandem blade can bring out its full potential in the two-dimensional flow control. Moreover, owing to the flow through the gap of the forward and rear blades, the aspiration flow rate required for the suppression of the three-dimensional corner stall can be reduced.

Research into aero acoustic characteristics of two-row impellers of the axial compressor

“…As shown by results obtained by other authors [2][3][4][5][6], the use of two-row blade crowns leads to an increase in the level of losses of full pressure. However, the problem on determining the influence of density of the grid of two-row impellers on the level of losses of full pressure remains unresolved.…”

“…Article [3] reports results concerning the influence of geometric parameters of a two-row blade crown on its aerodynamic characteristics. In paper [4], authors obtained characteristics for the stage of an axial compressor with a swivel two-row guiding device. Research results indicate that the use of a two-row blade crown makes it possible to increase pressure in the stage.…”

“…It is shown that the gas-dynamic effect on current makes it possible to improve the aerodynamic characteristics of blade crowns. Thus, research results reported in papers [2][3][4][5][6][7] show that the use of the two-row blade crows makes it possible to increase the pressure of compressor.…”

Flow control using unsteady pulsed holed suction with different excitation models in a highly loaded compressor cascade

“…This similar flow phenomenon is also observed in highly loaded compressors of the experimental study by Nerger et al 36 and the numerical study by Zhang and Wang. 37 Although some additional vortex structures on the lower endwall are generated, the intensity of these vortex structures is very weak in terms of that of high-loss area in the unexcited case, whereas the rises of loss are very limited, which can be proved in Figures 17 and 18. At the same time, the vortex structures in compressor passages attract each other and induce the other surrounding vortex structures, simultaneously shedding downstream periodically in an orderly way according to the excitation frequency, which has already been described well above in Figure 11.…”

Effect of tip clearance dimension on unsteadiness in a low-reaction aspirated transonic compressor rotor

“…A considerable amount of literature has been published on LRAC. [1][2][3][4][5] With the application of boundary layer suction in stator vanes, two methods were put forward to realize the low-reaction design concept. The one for subsonic aspirated compressors was increasing the prewhirl angle of the rotor, which reduced the flow diffusion load in the rotor so as to control the boundary layer separation.…”