Effect of inlet conditions on compressor intermediate duct

Gao, Limin; Deng, Xiaoming; Feng, Xudong; Yang, Zeyu

doi:10.1177/0954410014542624

Cited by 13 publications

(6 citation statements)

References 6 publications

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“…For the core duct, Gao et al. 31 suggest that at least 57 cells in the spanwise direction are required to model the flow pattern in the S-duct efficiently. The same strategy is used in this paper (69 spanwise cells in this study, refinement has shown changes lesser than defined grid-independent error band).…”

Section: Numerical Solver and Meshingmentioning

confidence: 99%

The effect of inlet distortion on low bypass ratio turbofan engines

Verma

Singh

Pradeep

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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Inlet flow non-uniformity, commonly known as inflow distortion, has been a long-standing problem in the history of gas turbine engines. Distortion can be present in the form of total pressure, total temperature or inflow incidence or any combinations of these. The search for better and robust performance requires engines that can sustain a large amount of inlet distortion without considerable loss in the thrust. In the present paper, the effect of total pressure distortion on a single-stage compressor and low bypass ratio fans are studied. Distortion near hub and tip in the form of step radial total pressure profiles is imposed at far upstream of the rotor leading edge. A systematic approach to qualitatively predict the performance maps in the presence of these distortions is discussed. Further, two extents of total pressure distortion are explored for constant inlet distortion intensity. Hub distortion is found to increase the stability margin, whereas tip distortion reduces it. On extending the distortion extent, hub distortion drastically reduces the stability margin, whereas a comparatively lower reduction in stability margin with tip distortion is observed. The critical distortion limit is observed by varying the inlet distortion extent. Also, it is found that downstream ducts in the bypass axial fan do not interact with the upstream fan. This can be exploited to perform independent simulations of the core engine from low bypass ratio fans. Hub distortion is found to drastically affect the duct performance owing to the presence of thicker upstream inlet boundary layer.

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Section: Numerical Solver and Meshingmentioning

confidence: 99%

The effect of inlet distortion on low bypass ratio turbofan engines

Verma

Singh

Pradeep

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Reference [11] showed a reduction in pressure gradient at hub and shroud but a rise in losses for a non-struted ICD. Gao et al [12] studied the same effect on a struted ICD. Results proved a significant dependency of secondary flow structure on swirl angle.…”

Section: Introductionmentioning

confidence: 97%

“…Influence of swirl on ICD flow behaviour has been studied by Ref. [11] and Gao et al [12]. Reference [11] showed a reduction in pressure gradient at hub and shroud but a rise in losses for a non-struted ICD.…”

Section: Introductionmentioning

confidence: 99%

On the effect of inter compressor duct length on compressor performance

2022

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Compression systems of modern, civil aircraft engines consist of three components: Fan, low-pressure compressor (LPC) and high-pressure compressor (HPC). The efficiency of each component has improved over the last decades by means of rising computational power which made high level aerodynamic optimisations possible. Each component has been addressed individually and separated from the effects of upstream and downstream components. But as much time and effort has been spend to improve performance of rotating components, the stationary inter-compressor duct (ICD) has only received minor attention. With the rotating compression components being highly optimised and sophisticated their performance potential is limited. That is why more aggressive, respectively shorter, ICDs get more and more into the focus of research and engine manufacturers. The length reduction offers high weight saving and thus fuel saving potential as a shorter ICD means a reduction in aircraft engine length. This paper aims at evaluating the impact of more aggressive duct geometries on LPC and HPC performance. A multi objective 3D computational fluid dynamics (CFD) aerodynamic optimisation is performed on a preliminary design of a novel two spool compressor rig incorporating four different operating line and two near-stall (NST) conditions which ensure operability throughout the whole compressor operating range. While the ICD is free to change in length, shape and cross-section area, the blades of LPC and HPC are adjusted for changing duct aerodynamics via profile re-staggering to keep number of free parameters low. With this parametrisation length, reductions for the ICD of up to 40% are feasible while keeping the reduction in isentropic efficiency at aerodynamic design point for the compressor below 1%pt. Three geometries of the Pareto front are analysed in detail focusing on ICD secondary flow behaviour and changes of aerodynamics in LPC and HPC. In order to asses changes in stall margin, speedlines for the three geometries are analysed.

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“… 14 , 15 Moreover, it has been demonstrated that inlet entry conditions have an impact on the S-duct aerodynamics. 16 , 17 Often, experimental testing and S-duct CFD optimization are required to assess the operability of the propulsion system for a range of different inlet configurations. 18 – 20 …”

Section: Introductionmentioning

confidence: 99%

S-duct flow distortion with non-uniform inlet conditions

Migliorini

Zachos

MacManus

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Convoluted aero-engine intakes are often required to enable closer integration between engine and airframe. Although the majority of previous research focused on the distortion of S-duct intakes with undistorted inlet conditions, there is a need to investigate the impact of more challenging inlet conditions at which the intake duct is expected to operate. The impact of inlet vortices and total pressure profiles on the inherent unsteady flow distortion of an S-duct intake was assessed with stereo particle image velocimetry. Inlet vortices disrupted the characteristic flow switching mode but had a modest impact on the peak levels and unsteady fluctuations. Non-uniform inlet total pressure profiles increased the peak swirl intensity and its unsteadiness. The frequency of swirl angle fluctuations was sensitive to the azimuthal orientation of the non-uniform total pressure distribution. The modelling of peak distortion with the extreme value theory revealed that although for some inlet configurations the measured peak swirl intensity was similar, the growth rate of the peak values beyond the experimental observations was substantially different and it was related with the measured flow unsteadiness. This highlights the need of unsteady swirl distortion measurements and the use of statistical models to assess the time-invariant peak distortion levels. Overall, the work shows it is vital to include the effect of the inlet flow conditions as it substantially alters the characteristics of the complex intake flow distortion.

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Effect of inlet conditions on compressor intermediate duct

Cited by 13 publications

References 6 publications

The effect of inlet distortion on low bypass ratio turbofan engines

The effect of inlet distortion on low bypass ratio turbofan engines

On the effect of inter compressor duct length on compressor performance

S-duct flow distortion with non-uniform inlet conditions

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