Unsteady blade pressures on a propfan - Predicted and measured compressibility effects

Nallasamy, M.

doi:10.2514/3.46554

Cited by 3 publications

(2 citation statements)

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“…In-plane forces can then be decomposed with projection on the reference axis in which vertical and side components are used. This decomposition of the in-plane forces is commonly found in many works in the literature [12,13,21] because the projection on the aircraft axis is straightforward. However, a modulus/angle decomposition (F IP , w IP ) is preferred in this work because aerodynamic mechanisms behind each term can be separated.…”

Section: Comparison and Analysis Of Resultsmentioning

confidence: 99%

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In-Plane Forces Prediction and Analysis in High-Speed Conditions on a Contra-Rotating Open Rotor

François

Laban

Costes³

et al. 2014

Journal of Turbomachinery

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Due to the growing interest from engine and aircraft manufacturers for contra-rotating open rotors (CROR), much effort is presently devoted to the development of reliable computational fluid dynamics (CFD) methodologies for the prediction of performance, aerodynamic loads, and acoustics. Forces transverse to the rotation axis of the propellers, commonly called in-plane forces (or sometimes 1P forces), are a major concern for the structural sizing of the aircraft and for vibrations. In-plane forces impact strongly the stability and the balancing of the aircraft and, consequently, the horizontal tail plane (HTP) and the vertical tail plane (VTP) sizing. Also, in-plane forces can initiate a flutter phenomenon on the blades or on the whole engine system. Finally, these forces are unsteady and may lead to vibrations on the whole aircraft, which may degrade the comfort of the passengers and lead to structural fatigue. These forces can be predicted by numerical methods and wind tunnel measurements. However, a reliable estimation of in-plane forces requires validated prediction approaches. To reach this objective, comparisons between several numerical methods and wind tunnel data campaigns are necessary. The primary objective of the paper is to provide a physical analysis of the aerodynamics of in-plane forces for a CROR in high speed at nonzero angle of attack using unsteady simulations. Confidence in the numerical results is built through a code-to-code comparison, which is a first step in the verification process of in-plane forces prediction. Thus, two computational processes for unsteady Reynolds-averaged Navier–Stokes (URANS) simulations of an isolated open rotor at nonzero angle of attack are compared: computational strategy, open rotor meshing, aerodynamic results (rotor forces, blades thrust, and pressure distributions). In a second step, the paper focuses on the understanding of the key aerodynamic mechanisms behind the physics of in-plane forces. For the front rotor, two effects are predominant: the first is due to the orientation of the freestream velocity, and the second is due to the distribution of the induced velocity. For the rear rotor, the freestream velocity effect is reduced but is still dominant. The swirl generated by the front rotor also plays a major role in the modulus and the direction of the in-plane force. Finally, aerodynamic interactions are found to have a minor effect.

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Section: Comparison and Analysis Of Resultsmentioning

confidence: 99%

“…The rotor-rotor interface was modeled with a mixing-plane condition [11]. First aerodynamic simulations of propellers at nonzero angle of attack at high-speed (Mach number from 0.6 to 0.8) were achieved by Nallasamy [12] in 1994. All the blades have to be accounted for in the computation because there are no flow periodicity relations.…”

Section: Introductionmentioning

confidence: 99%