Effect of Truncation on the Performance of Busemann Inlet

Zhao, Zhi Long; Song, Wenyan

doi:10.5539/mas.v3n2p168

Cited by 9 publications

(6 citation statements)

References 4 publications

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“…Also, the lack of an initial inward deflection places all required structural thickness to be outside the nacelle, and defeats the purpose of using an inward-turning flowfield to reduce sonic boom and drag. Techniques for truncation of Busemann flowfields for hypersonic applications have been reported [3][4][5][6][7][8] but all introduce significant nonuniformity in the outflow.…”

Section: Introductionmentioning

confidence: 99%

Inward-Turning Streamline-Traced Inlet Design Method for Low-Boom, Low-Drag Applications

Otto

Trefny

Slater

2016

Journal of Propulsion and Power

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A new design method for inward-turning, streamline-traced inlets is presented. Resulting designs are intended for low supersonic, low-drag, low-boom applications such as that required for NASA's proposed low-boom flight demonstration aircraft. A critical feature of these designs is the internal cowl lip angle that allows for little or no flow turning on the outer nacelle. Present methods using conical-flow "Busemann" parent flowfields have simply truncated, or otherwise modified the stream-traced contours to include this internal cowl angle. Such modifications disrupt the parent flowfield, reducing inlet performance and flow uniformity. The method presented herein merges a conical flowfield that includes a leading shock with a truncated Busemann flowfield in a manner that minimizes unwanted interactions. A leading internal cowl angle is now inherent in the parent flowfield, and inlet contours traced from this flowfield retain its high performance and good flow uniformity. CFD analysis of a candidate inlet design is presented that verifies the design technique, and reveals a "starting" issue with the basic geometry. A minor modification to the cowl lip region is shown to eliminate this phenomenon, thereby allowing starting and smooth transition to sub-critical operation as back-pressure is increased. An inlet critical-point total pressure recovery of 96% is achieved based on CFD results for a Mach 1.7 freestream design. Correction for boundary-layer displacement thickness, and sizing for a given engine airflow requirement are also discussed.

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Section: Introductionmentioning

confidence: 99%

Inward-Turning Streamline-Traced Inlet Design Method for Low-Boom, Low-Drag Applications

Otto

Trefny

Slater

2016

Journal of Propulsion and Power

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“…As opposed to the conical flow, the flow inside Busemann intake is turned inward to the center line axis. The calculation process is also reversed where the calculation must be started at the downstream area of the intake [5]. Therefore, it needs boundary condition such as the exit Mach number, the freestream Mach number, and the terminal shockwave angle.…”

Section: ) the Expansion Fan Is An Isentropic Processmentioning

confidence: 99%

“…In this inlet section, an isentropic compression process occurs. The flow in this section is turned inward respecting the Taylor-Maccoll equation and at the same time decreasing flow's Mach number [5]. In contrast to ICFA section where the wall is constant at certain angle, the Inward Turning section (or Busemann Inlet section) wall is generated from flow's streamline that respects the Busemann Parent Flowfield generated from the Taylor-Maccoll equation.…”

Section: B Busemann Inlet Design Calculationmentioning

confidence: 99%

“…Inward-turning intake then is introduced to weaken the terminal shockwave. This design has several advantages including reducing shockwave drag, noise, and may also eliminate the complex support system for the intake such as adjustable spike position [3][4][5][6][7]. One of the well-known inward-turning intake is Busemann intake which theoretically the most efficient supersonic intake.…”

Section: Introductionmentioning

confidence: 99%

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Design of Inward-Turning External Compression Supersonic Inlet for Supersonic Transport Aircraft

Utomo

Bura²

2019

ins

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Inward-turning external compression intake is one of the hybrid intakes that employs both external and internal compression intakes principle. This intake is commonly developed for hypersonic flight due to its efficiency and utilizing fewer shockwaves that generate heat. Since this intake employ less shockwaves, this design can be applied for low supersonic (Mach 1.4 - 2.5) intakes to reduce noise generated from the shockwaves while maintaining the efficiency. Other than developing the design method, a tool is written in MATLAB language to generate the intake shape automatically based on the desired design requirement. To investigate the intake design tool code and the performance of the generated intake shape, some CFD simulation were performed. The intake design tool code can be validated by comparing the shockwave location and the air properties in every intake's stations. The performance parameters that being observed are the intake efficiency, flow distortion level at the engine face, and the noise level generated by the shockwaves. The design tool written in MATLAB is working as intended. Two dimensional axisymmetric CFD simulations validation has been done and the design meets the minimum requirement. As for the 3D inlet geometry, with a little modification on diffuser and equipping vent to release the buildup pressure, the inlet has been successfully met the military standard on inlet performance (MIL-E-5007D). This design method also has feature to fit every possible throat cross sectional shapes and has been proven to work as designed.Keywords— Inward-turning, Supersonic, Engine Intakes, Low- noise, Design Method

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“…The truncation effect was also investigated in a numerical study for inviscid flows by Zhao and Song [15], up to truncation angles of δ 6 deg. Zhao reported that, with increasing truncation angle, a stronger oblique shock emanates from the leading edge and that it distorts the flowfield.…”

Section: Leading Edge Truncationmentioning

confidence: 99%

Viscous Effects and Truncation Effects in Axisymmetric Busemann Scramjet Intakes

Flock

Gülhan

2016

AIAA Journal

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During Busemann intake design, two constraints have to be considered. First, caused by the displacement of the boundary layer, the pressure levels in a Busemann intake were higher (≈40%) than the values predicted analytically; these effects were labeled viscous effects. Second, truncating the flowfield also changed the properties of the classical Busemann flow; these effects were labeled truncation effects, and it can be distinguished between truncating the intake at the leading edge and at the rear side. To take into account viscous effects, the boundary-layer displacement thickness was calculated with an integral method and added to the inviscid Busemann contour. To quantify leadingedge truncation effects, an oblique shock at the leading edge was assumed, and the pressure at the intake exit was corrected with the continuity equation. The change in flow properties during the rear-side truncation was calculated with a stream-thrust analysis. The effects were separately investigated with Reynolds-averaged Navier-Stokes and Euler simulations, respectively. After the viscous correction, the deviation between numerically and analytically calculated pressure level was below 10%. When truncating the intake, the numerically calculated average pressure and temperature levels were within 1% of the analytical values.

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Effect of Truncation on the Performance of Busemann Inlet

Cited by 9 publications

References 4 publications

Inward-Turning Streamline-Traced Inlet Design Method for Low-Boom, Low-Drag Applications

Inward-Turning Streamline-Traced Inlet Design Method for Low-Boom, Low-Drag Applications

Design of Inward-Turning External Compression Supersonic Inlet for Supersonic Transport Aircraft

Viscous Effects and Truncation Effects in Axisymmetric Busemann Scramjet Intakes

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