Aircraft System Study of Boundary Layer Ingesting Propulsion

Hardin, Larry W.; Tillman, Gregory; Sharma, Om P.; Berton, Jeffrey J.; Arend, David J.

doi:10.2514/6.2012-3993

Cited by 78 publications

(75 citation statements)

References 4 publications

(9 reference statements)

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“…However, the benefit was lower: the analysis of the BWB developed for the Cambrigde-MIT Silent Aircraft Initiative (SAX40) resulted in a PSC of up to four percent. A similar value is reported in [5] for a BWB derived from the SAX40 aircraft. On the experimental side, the investigations with the model of the D8 aircraft (double bubble) have to be mentioned .…”

Section: Boundary Layer Ingestionsupporting

confidence: 63%

“…Since it is a mature technology, new concepts such as boundary layer ingestion (BLI), which is closely connected to embedded engines, have to be taken into account to get a relevant benefit. Previous studies in this field revealed a promising potential for all kinds of aircraft concepts [3][4][5][6][7] and encouraged the present work. The intention was to develop a fast tool for basic performance analyses of a single propulsor in the presence of BLI and it should be decoupled from a concrete aircraft design.…”

Section: Introductionmentioning

confidence: 88%

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Modelling of A Boundary Layer Ingesting Propulsor

Budziszewski

Friedrichs

2018

Energies

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Boundary layer ingestion is a promising method to decrease the propulsive power consumption of an aircraft, and therefore the fuel consumption. This leads to a reduced environmental impact and an improved cost-efficiency. To get a better understanding of this method and to estimate its benefits, the modelling of a propulsor located at the upper rear centerbody of a blended wing body aircraft is presented in this paper. A parallel compressor model approach is used to analyse the impact of the ingested low velocity fluid which leads to a non-uniform inflow. The required boundary layer data are generated with an analysis tool for 2D subsonic airfoils. Some parameter variations are conducted with the developed programme to study their impact on the power saving potential. In addition, a simple estimation for the benefit of embedded aeroengines is given. Despite the drawback from fan efficiency due to the inflow distortion, the results show a significant decrease in required propulsive power for boundary layer ingestion in combination with integrated engines.

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Section: Boundary Layer Ingestionsupporting

confidence: 63%

Section: Introductionmentioning

confidence: 88%

Modelling of A Boundary Layer Ingesting Propulsor

Budziszewski

Friedrichs

2018

Energies

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“…Hardin, et al 15 used an NPSS model of a typical ultra-high bypass (UHB) turbofan engine to determine performance changes due to BLI-type distortion. To account for performance losses due to reduced fan efficiency and increased inlet total pressure losses, the engine's TSFC sensitivity to various values of fan efficiency and inlet total pressure recovery was calculated in NPSS.…”

Section: Bli Studiesmentioning

confidence: 99%

Effect of BLI–Type Inlet Distortion on Turbofan Engine Performance

Lucas

O’Brien

Ferrar

2014

Volume 1A: Aircraft Engine; Fans and Blowers

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Boundary Layer Ingestion (BLI) is currently being researched as a potential method to improve efficiency and decrease emissions for the next generation of commercial aircraft. While reenergizing the boundary layer formed over the fuselage of an aircraft has many system level benefits, ingesting the low velocity boundary layer flow through a serpentine inlet into a turbofan engine adversely affects the performance of the engine. The available literature has only yielded studies of the effects of this specific type of inlet distortion on engine performance in the form of numerical simulations. This work seeks to provide an experimental analysis of the effects of BLI-type distortion on a turbofan engine's performance. A modified JT15D-1 turbofan engine was investigated in this study. Inlet flow distortion was created by a layered wire mesh distortion screen designed to create a total pressure distortion profile at the aerodynamic interface plane (AIP) similar to NASA's Inlet A boundary layer ingesting inlet flow profile. Results of this investigation showed a 15.5% decrease in stream thrust and a 14% increase in TSFC in the presence of BLI-type distortion.Flow measurements at the AIP and the bypass nozzle exit plane provided information about the losses throughout the fan flow path. The presence of the distortion screen resulted in a 24% increase in mass-averaged entropy production along the entire fan flow path compared to the non-distorted test. A mass-averaged fan flow path efficiency was also calculated assuming an isentropic process as ideal. The non-distorted fan flow path efficiency was computed to be 60%, while the distorted fan flow path efficiency was computed to be 50.5%, a reduction in efficiency of 9.5%. The entropy generation between ambient conditions and the AIP was compared to the entropy production along the entire fan flow path. It was found that the majority of entropy generation occurred between the AIP and bypass nozzle exit. Based on flow measurements at the bypass nozzle exit plane, it was concluded that inlet flow distortion should be located away from the tip region of the fan in order to minimize losses in a very lossy region. It was also determined that the fan and bypass duct process the different regions of the total pressure distortion in different ways. In some regions the entropy production decreased for the distorted test compared to the clean test, while in other regions the entropy production increased for the distorted test compared to the clean test. Finally, it was found that small improvements in total pressure and total temperature variation at the bypass nozzle exit plane will greatly improve the fan flow path efficiency and entropy generation, thereby decreasing performance losses.iii

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“…As mentioned in [4,5,7]; BLI requires a deeper and broader analysis in aspects such as PAI, engines installation, flow control, inlet design, and mainly, it is required to analyse the effect of BLI in the performance of the whole aircraft, not only in the propulsion system. This work examines, at a preliminary design stage, another potential benefit of BLI.…”

Section: Introductionmentioning

confidence: 99%

“…These studies determined aerodynamic coefficients for both configurations and evaluated the Propulsor-Airframe Integration (PAI) through computational fluid dynamics (CFD) and wind tunnel experiments at high Reynolds numbers about 75 million and a Mach number of 0.85 [6]. Whilst, Hardin [7] estimated the fraction of viscous drag that could be ingested, and determined that BLI propulsors can reduce from 3% up to 5% the fuel burn rate, for BLI fractions between 10% and 12% (Drag ingested/ Total Drag). All the aforementioned works were conducted on baseline configurations of BWB transport aircrafts.…”

Section: Introductionmentioning

confidence: 99%

Weight assessment for a blended wing Body-Unmanned aerial vehicle implementing boundary layer ingestion

Valencia

Alulema

Hidalgo

2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Boundary Layer Ingestion (BLI) has been studied extensively for implementation in Blended Wing Body (BWB) transport aircrafts, and it has been reported that BLI offers potential benefits mainly in terms of energy, improving the propulsive efficiency of a propulsion system and reducing the fuel consumption. This paper examines potential benefits of BLI related with a reduction on the Take-Off Gross Weight (TOGW) for a BWB-Unmanned Aerial Vehicle (UAV). It is discussed the methodology for weight estimation of a BWB-UAV through parametric models. To evaluate the benefits of BLI in terms of weight reduction, it has been taken into account the removal of pylons and the nacelle weight reduction when embedding nacelles into the airframe. The validation of the parametric models, and the case of study have been carried out for the aircraft NASA X-48B. The results show a reduction in TOGW between 8% and 19% when removing pylons and embedding nacelles into the airframe. IntroductionThe benefits of boundary layer ingestion (BLI) have been evaluated extensively with a special focus on Blended Wing Body (BWB) transport aircrafts. Most of previous studies about BLI for transport aircrafts have focussed mainly on design of inlets, reduction on fuel consumption, improvement of propulsive efficiency, ram and viscous drag reduction, aeroacoustics effects, and flow control at duct inlet. In 1998, Liebeck [1] introduces BLI in the design of a subsonic BWB transport aircraft, and the results show a reduction of 13% on thrust to weight ratio, and a reduction of 27% on fuel burned, compared to a conventional aircraft operating at the same conditions. Rodriguez [2] performed a multidisciplinary design optimization (MDO) of BLI inlets, and estimated a reduction of 3.7% in fuel burn rate, and 2.3% in total drag coefficient. In 2004, a design optimization of a BWB subsonic transport was developed by Liebeck [3]; in his work, BLI was evaluated experimentally, simulating the boundary layer over a flat plate and testing different duct geometries. A. Plas [4] assessed the performance of a BLI propulsion system; to evaluate the benefits of BLI in terms of energy, Plas considered power saving coefficient as figure of merit. For the "Silent aircraft", Plas estimated a power saving between 3% and 4% when embedding nacelles into the BWB airframe [4].Campbell [5] and Carter [6] designed and tested 2 scale models of a BWB aircraft: a clean wing BWB, and a BWB with BLI nacelles. These studies determined aerodynamic coefficients for both configurations and evaluated the Propulsor-Airframe Integration (PAI) through computational fluid dynamics (CFD) and wind tunnel experiments at high Reynolds numbers about 75 million and a Mach number of 0.85 [6].

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Aircraft System Study of Boundary Layer Ingesting Propulsion

Cited by 78 publications

References 4 publications

Modelling of A Boundary Layer Ingesting Propulsor

Modelling of A Boundary Layer Ingesting Propulsor

Effect of BLI–Type Inlet Distortion on Turbofan Engine Performance

Weight assessment for a blended wing Body-Unmanned aerial vehicle implementing boundary layer ingestion

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