热科学学报 Journal of Thermal Science【引用格式】Amit KUMAR, Jerry T. JOHN, A.M. PRADEEP, R.A.D. AKKERMANS, Dragan KOZULOVIC,Aerodynamics of a Tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds,Journal of Thermal Science, 2024, 33(4): 1340-1356.
7.Aerodynamics of a Tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds
Amit KUMAR, Jerry T. JOHN, A.M. PRADEEP, R.A.D. AKKERMANS, Dragan KOZULOVIC
Department of Aerospace Engineering, Indian Institute of Technology Bombay, Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, Institute of Jet Propulsion, Bundeswehr University Munich
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https://doi.org/10.1007/s11630-024-1965-5
Journal of Thermal Science, 2024, 33(4): 1340-1356.
Abstract:
For most aircraft engines, inflow
distortion is inevitable. Inflow distortion is known to degrade the aerodynamic
performance and stable operating limits of a compressor. Tandem rotor
configuration is an arrangement that effectively controls the growth of the
boundary layer over the suction surface of the blade. Therefore, a higher total
pressure rise can be achieved through this unconventional design approach
involving the splitting of the blade into forward and aft sections. It is
expected that the effect of inlet flow distortion would be more severe for a
tandem-rotor design due to the greater flow turning inherent in such designs.
However, this aspect needs to be thoroughly examined. The present study
discusses the effect of circumferential distortion on the tandem-rotor at
different rotational speeds. Full-annulus RANS simulations using ANSYS CFX are
used in the present study. The performance of the rotor at a particular flow
coefficient and different rotational speeds is compared. The total pressure and
efficiency are observed to drop at lower mass flow rates under the influence of
circumferential distortion. The loss region in each blade passage is mainly
associated with the blade wake, tip leakage vortex, secondary flow, and
boundary layer. However, their contribution varies from passage to passage,
particularly in the distorted sector. At the lower span, the wake width is
found to be higher than that at a higher span. Due to the redistribution of the
mass flow, the circumferential extent reduces at a higher span. In the
undistorted sector, the strength of the tip leakage vortex is significantly
higher at the design rotational speed than at lower speeds. The distortion near
the tip region promotes an early vortex breakdown even at the design operating
condition. This adversely affects the total pressure, efficiency, and stall
margin. Under clean flow conditions, this phenomenon is only observed near the
stall point. At the design operating condition, the breakdown of the forward
rotor tip leakage vortex is detected in four blade passages. The axial velocity
deficit and adverse pressure gradient play a significant role in the behaviour
of tip leakage vortex at lower rotational speeds in the distorted sector. A
twin vortex breakdown is also observed at lower speeds.
