Investigation of subsonic nacelle performance improvement concept

Dusa, D.; Lahti, D. J.; Berry, Douglas H.

doi:10.2514/6.1982-1042

Cited by 12 publications

(7 citation statements)

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“…The quantity is about 0.8~1.1% for real engine [4]. It's really a big thrust loss as it is equivalent with 3~4 drag counts.…”

Section: Introductionmentioning

confidence: 96%

“…The nacelle is calibrated in the Flight Simulation Chamber to determine the nozzle performance, including velocity coefficient and discharge coefficient. The coefficients are used for calculating the thrust loss and internal drag of nozzle [4]. The accuracy of the coefficients is very important for the nacelle internal drag calculation.…”

Section: Introductionmentioning

confidence: 99%

“…It's really a big thrust loss as it is equivalent with 3~4 drag counts. The thrust and thrust loss of engine are measured by the Flight Simulation Chamber (FSC) [4] [5]. The nacelle is calibrated in the Flight Simulation Chamber to determine the nozzle performance, including velocity coefficient and discharge coefficient.…”

Section: Introductionmentioning

confidence: 99%

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Performance Prediction of Conical Nozzle using Navier-Stokes Computation

Chen

2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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In the Propulsion Aerodynamics Workshop I, the conical nozzles are numerically investigated in present paper. Axisymmetric, three-dimensional, and unsteady computations are conducted for three types of test cases. The effects of base drag and free stream Mach number on velocity coefficient are analyzed. The results of axisymmetric computation show that, the discharge coefficient and velocity coefficient match well with the experimental data. The wall Mach number and sonic line are also well predicted. The shock reflection phenomenon is well captured by the fine grid. The velocity coefficient of three-dimensional computation is about 0.1% higher than the axisymmetric computation. When the pressure ratio is very high, the three-dimensional RANS results may be not reliable as the normal shock induces unsteady recirculation zone . Three-dimensional results with splitter plate in the nozzle show that, the shock wave location and shock reflection phenomenon are changed by the splitter plate. Unsteady zonal SST-DES method is also used to simulate the vortex shedding of the splitter plate. A main shedding frequency of 32.2 kHz is obtained by analyzing the viscous force of the splitter trailing edge.

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“…The quantity is about 0.8~1.1% for real engine [4]. It's really a big thrust loss as it is equivalent with 3~4 drag counts.…”

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance Prediction of Conical Nozzle using Navier-Stokes Computation

Chen

2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…The aerodynamic pressure and viscous forces exerted on the walls of the exhaust system can have a significant impact on the gross propulsive force F G . According to Dusa et al ( 10 ) , the reduction in F G due to non-isentropic flow conditions can reach approximately 1.5–2.0% relative to the case of ideal flow expansion to ambient static pressure. It is standard practice to quote the aerodynamic behaviour of an exhaust system relative to that of an ideal nozzle through the definition of the non-dimensional discharge and velocity coefficients, C D and C V , respectively ( 11 , 12 ) .…”

Section: 0 Introductionmentioning

confidence: 99%

Design optimisation of separate-jet exhausts for the next generation of civil aero-engines

et al. 2018

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The next generation of civil large aero-engines will employ greater bypass ratios compared with contemporary architectures. This results in higher exchange rates between exhaust performance and specific fuel consumption (SFC). Concurrently, the aerodynamic design of the exhaust is expected to play a key role in the success of future turbofans. This paper presents the development of a computational framework for the aerodynamic design of separate-jet exhaust systems for civil aero-engines. A mathematical approach is synthesised based on class-shape transformation (CST) functions for the parametric geometry definition of gas-turbine exhaust components such as annular ducts and nozzles. This geometry formulation is coupled with an automated viscous and compressible flow solution method and a cost-effective design space exploration (DSE) approach. The framework is deployed to optimise the performance of a separate-jet exhaust for very-high-bypass ratio (VHBR) turbofan engine. The optimisations carried out suggest the potential to increase the engine’s net propulsive force compared with a baseline architecture, through optimum exhaust re-design. The proposed method is able to identify and alleviate adverse flow-features that may deteriorate the aerodynamic behaviour of the exhaust system.

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“…The gross propulsive force F G produced by the exhaust system can be substantially influenced by the aerodynamic pressure and viscous forces exerted on the walls of the bypass duct and nozzle, core after-body, and protruding core plug. Dusa et al [4] reported that for high-bypass ratio turbofan engines, the gross thrust loss due to non-isentropic flow conditions can be of the order of 1.5-2.0% relative to the ideal case of fully-expanded isentropic flow. To establish a standard accounting process, it is common practice to compare the actual nozzle performance with that of an ideal nozzle through the definition of the nondimensional discharge and velocity coefficients, C D and C V , respectively [5,6].…”

mentioning

confidence: 99%

Civil turbofan engine exhaust aerodynamics: Impact of bypass nozzle after-body design

Goulos

Stańkowski

MacManus

et al. 2018

Aerospace Science and Technology

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It is envisaged that the next generation of civil large turbofan engines will be designed for greater bypass ratios when compared to contemporary architectures. The underlying motivation is to reduce specific thrust and improve propulsive efficiency. Concurrently, the aerodynamic performance of the exhaust system is anticipated to play a key role in the success of future engine architectures. The transonic flow topology downstream of the bypass nozzle can be significantly influenced by the after-body geometry. This behavior is further complicated by the existence of the air-flow vent on the nozzle after-body which can have an impact on the performance of the exhaust system. This paper aims to investigate the aerodynamics associated with the geometry of the bypass nozzle after-body and to establish guidelines for the design of separate-jet exhausts with respect to future large turbofan engines. A parametric geometry definition has been derived based on Class-Shape Transformation (CST) functions for the representation of post-nozzle-exit components such as after-bodies, plugs, and air-flow vents. The developed method has been coupled with an automatic mesh generation and a Reynolds Averaged Navier-Stokes (RANS) flow solution method, thus devising an integrated aerodynamic design tool. A cost-effective optimization strategy has been implemented consisting of methods for Design Space Exploration (DSE), Response Surface Modeling (RSM), and Genetic Algorithms (GAs). The combined approach has been deployed to explore the aerodynamic design space associated with the bypass nozzle after-body geometry for a Very High Bypass Ratio (VHBR) turbofan engine with separate-jet exhausts. A detailed investigation has been carried out to expose the transonic flow mechanisms associated with the effect of after-body curvature combined with the

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Investigation of subsonic nacelle performance improvement concept

Cited by 12 publications

References 0 publications

Performance Prediction of Conical Nozzle using Navier-Stokes Computation

Performance Prediction of Conical Nozzle using Navier-Stokes Computation

Design optimisation of separate-jet exhausts for the next generation of civil aero-engines

Civil turbofan engine exhaust aerodynamics: Impact of bypass nozzle after-body design

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