Influence of Blade Sweep on the Energetic Behavior of Axial Flow Turbomachinery Rotors at Design Flow Rate

Abstract

Experimental and computational studies were carried out in order to survey the energetic aspects of forward and backward sweep in axial flow rotors of low aspect ratio blading for incompressible flow. It has been pointed out that negative sweep tends to increase the lift, the flow rate and the ideal total pressure rise in the vicinity of the endwalls. Just the opposite tendency was experienced for positive sweep. The local losses were found to develop according to combined effects of sweep near the endwalls, endwall and tip clearance losses, and profile drag influenced by re-arrangement of the axial velocity profile. The forward-swept bladed rotor showed reduced total efficiency compared to the unswept and swept-back bladed rotors. This behavior has been explained on the basis of analysis of flow details. It has been found that the swept bladings of low aspect ratio tend to retain the performance of the unswept datum rotor even in absence of sweep correction.

Optimization of Blade Sweep in a Transonic Axial Compressor Rotor

“…9 (a), solid line represents the reference blade. It is noted that a backward-swept blade is more effective in increasing the adiabatic efficiency, which has been reported in the previous study (9) . Distributions of total pressure, total temperature and adiabatic efficiency for the reference and the optimized shapes, which are tangentially averaged at the exit of the rotor, are shown along the spanwise direction in Figs.…”

“…They showed that the stall margin was significantly improved with the forward swept blade although a very little change in the peak efficiency was produced by the blade sweep or lean. In addi-tion, Janos Vad, et al (9) studied experimentally as well as numerically the aspects of forward-and backward-sweep in axial flow rotors having low aspect ratio blade for incompressible flow. Their studies showed that the forwardswept bladed rotor reduces total efficiency compared to the unswept and backward-swept bladed rotors.…”

Aerodynamic effects of forward blade skew in axial flow rotors of controlled vortex design

“…The performance and loss modifying aspects of forward sweep/skew, which are specific to the individual case studies as the above literature overview suggests, are closely related to the three-dimensional (3D) features of the blade passage flow [12,14,15]. Such 3D flow features are especially characteristic for rotors of CVD, due to the spanwise blade circulation gradient and the resultant vorticity shed from the blade [2].…”

Study of the Aero-Acoustic and Aerodynamic Effects of Soft Coating upon Airfoil

“…Above this threshold, only moderate efficiency improvement is expected. Since the fan efficiency is closely related to the lift and drag of the blade sections (14) , the above yield that only minor changes are expected in c L and c D of a blade section -or of an airfoil being in aerodynamic analogy with the blade section -above Reynolds number ≈ 150 000. Indeed, as the data in Ref.…”