Body-force modeling for aerodynamic analysis of air intake – fan interactions

Thollet, William; Dufour, Guillaume; Carbonneau, Xavier; Blanc, Florian Sell-Le

doi:10.1108/hff-07-2015-0274

Cited by 28 publications

(15 citation statements)

References 15 publications

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“…To this end, body-force methods represent an interesting way of reducing computational cost. Several models have already shown promising results not only to reproduce potential fan stage effects on inlet aerodynamics [1,23,2,24] but also to describe fan working conditions [25,26,27], notably in distorted conditions [17,28].…”

Section: Introductionmentioning

confidence: 99%

Efficient Design Investigation of a Turbofan in Distorted Inlet Conditions

Godard¹,

Jaeghere

Gourdain

2019

Volume 2A: Turbomachinery

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Designing a turbofan to operate in distorted inlet conditions is an issue of growing interest. In such conditions however, fan design can be computationally challenging. Indeed, subject to neither axi-symmetrical nor periodic inlet conditions, computations must be carried out throughout the whole circumferential domain i.e. 360°. Besides, the classical CFD approach implies the use of URANS computations so as to capture the distortion transfer across the fan stage. Eventually, computations are too onerous to be used in design loops. In this context, this paper presents a methodology to effectively assess a fan blade design domain in distorted conditions. This methodology is based on a body-force source term approach formulated in order to accurately recreate deviations, loads and losses across the fan stage. It notably enables to gain two orders in terms of restitution time and thus the possibility to use optimization tools. The design domain of this study is based on variations of profile chord, blade leading and trailing edges angles applied at two different relative heights. A Latin Hypercube Sampling (LHS) associated with a meta-model based on Radial Basis Functions (RBF) enables to assess the impact of geometric variations on performance and operability. Although this study emphasizes that some modeling improvements are still necessary, it also demonstrates the potential of the body-force methodology to conduct fan design when subject to inlet distortion.

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Section: Introductionmentioning

confidence: 99%

Efficient Design Investigation of a Turbofan in Distorted Inlet Conditions

Godard¹,

Jaeghere

Gourdain

2019

Volume 2A: Turbomachinery

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“…To better account for the fan aerodynamic interactions with the external aerodynamic flowfields around the aircraft for these increasingly more complex engine-airframe integration scenarios, the need to employ higher-fidelity fan modeling approaches than the classical engine boundary condition used in typical aerodynamic assessment of the entire configuration has been a growing focus in research projects and industrial applications. The main focus has been on developing simulation strategies accounting for the fan using actuator disc or body force models as well as the full geometric modeling of the low-pressure system of the turbofan in full annulus uRANS CFD analyses [2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Stuermer¹

2019

Aerospace

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In the context of an increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards larger bypass ratio engine designs, with Ultra-High Bypass Ratio (UHBR) engines becoming a likely power plant option for future commercial transport aircraft. These engines promise low specific fuel consumption at the engine level, but the resulting size of the nacelle poses challenges in terms of the installation on the airframe. Thus, their integration on an aircraft requires careful consideration of complex engine–airframe interactions impacting performance, aeroelastics and aeroacoustics on both the airframe and the engine sides. As a partner in the EU funded Clean Sky 2 project ASPIRE, the DLR Institute of Aerodynamics and Flow Technology is contributing to an investigation of numerical analysis approaches, which draws on a generic representative UHBR engine configuration specifically designed in the frame of the project. In the present paper, project results are discussed, which aimed at demonstrating the suitability and accuracy of an unsteady RANS-based engine modeling approach in the context of external aerodynamics focused CFD simulations with the DLR TAU-Code. For this high-fidelity approach with a geometrically fully modeled fan stage, an in-depth study on spatial and temporal resolution requirements was performed, and the results were compared with simpler methods using classical engine boundary conditions. The primary aim is to identify the capabilities and shortcomings of these modeling approaches, and to develop a best-practice for the uRANS simulations as well as determine the best application scenarios.

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“…Among different types of inlet distortions, the total pressure distortion is one of the most common forms compressor theory (Mazzawy, 1977;Pearson & McKenzie, 1959), actuator disks (Hawthorne et al, 1978;Horlock, 1979), simple semi-empirical methods (Valencia et al, 2017), through-flow analysis (Hall et al, 2017) and body force methods (Guo & Hu, 2018;Thollet et al, 2016). Although these methodologies can get the features of non-uniform inflow redistributions across the rotor through low computational cost, many flow details such as the secondary flows in compressors can't be well and fully captured due to the corresponding assumptions and simplifications.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a transonic axial-flow compressor under inlet total pressure distortion to enhance aerodynamic performance

Yang

et al. 2020

Engineering Applications of Computational Fluid Mechanics

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In a boundary layer ingestion (BLI) propulsion system, the compressor rotor operates under the condition of a severe inflow distortion because the boundary layers on the surface of aircraft have been ingested. In this situation, the low-momentum fluid would inevitably raise the blade load and aggravate the local aerodynamic losses, thus severely deteriorating the compressor overall aerodynamic performance. The paper has applied a sweep optimization design based on surrogate model and genetic algorithm to a transonic axial-flow compressor at the condition of total pressure distorted inflow. The optimization objective is to improve the compressor efficiency. The sweep design has been implemented through controlling the shape of the blade stacking line and the time-saving steady numerical simulations are mainly utilized in the optimization process. Then, the full-annulus unsteady CFD calculations have been conducted for validating the optimized design and further analyzing the flow mechanisms of performance improvements. The computational results show that the inflow distortion has led to non-uniform distributions of the tip leakage loss and the hub flow separation loss along the circumferential direction. It is found that the rotor blade has suffered from the highest tip leakage losses and hub separation losses during the blade leaving the distorted region. After rotor sweep optimization, both tip leakage and hub separation losses have been notably reduced along the full circumferential direction. Moreover, for different pitchwise locations, the optimized rotor sweep design has achieved more aerodynamic performance improvements in the process of the rotor blade leaving the distorted region than those in the processes of the rotor blade moving out of, moving towards and entering the distorted region. Overall, the optimized design performs better than the baseline design in terms of adiabatic efficiency in the entire operating range. In the meanwhile, the total pressure ratio has been maintained. Specifically, an approximately 0.5% increment of efficiency has been achieved by the optimized design at the optimization point. For this paper, the major purpose is to offer useful guidelines for fan/compressor design strategy to achieve high aerodynamic performances under distorted inflow working condition.

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Body-force modeling for aerodynamic analysis of air intake – fan interactions

Cited by 28 publications

References 15 publications

Efficient Design Investigation of a Turbofan in Distorted Inlet Conditions

Efficient Design Investigation of a Turbofan in Distorted Inlet Conditions

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Optimization of a transonic axial-flow compressor under inlet total pressure distortion to enhance aerodynamic performance

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