The StreamVane Method: A New Way to Generate Swirl Distortion for Jet Engine Research

Hoopes, Kevin; O’Brien, Walter F.

doi:10.2514/6.2013-3665

Cited by 25 publications

(14 citation statements)

References 7 publications

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“…Flow in the inlet of a full-scale research engine is distorted by a 21-in diameter swirl distortion screen previously designed [13]. The distorted flow, based on the distortion present in the turbofan inlet of a hybrid wing body airframe, is characterized experimentally.…”

Section: Resultsmentioning

confidence: 99%

“…It is imperative that these distortions are known and their impact fully understood in the initial steps of the aircraft design to ensure satisfactory operability. Total pressure and temperature distortions have been long analyzed [6][7][8][9][10], while swirl distortions, as relevant as they are, have only recently been successfully simulated and analyzed at laboratory and ground testing scales [11][12][13]. Figure 1 shows a rendering of NASA's hybrid wing body (HWB) aircraft concept, developed as part of the Environmentally Responsible Aviation program, with the main objective of reducing noise and fuel consumption.…”

Section: Introductionmentioning

confidence: 99%

“…The HWB distortion profile-indicative of airframe vortex ingestion-is the object of the swirl distortion study in this work. Here, the StreamVane TM technology [13,17] is used to generate a distortion profile inspired by the base distortion features of an extreme flight condition for an experimental design of a HWB engine inlet. Prior findings on StreamVane aerodynamics indicate that the dominant secondary flow dynamics are Reynolds number independent [17,18], and that the generation of the distortions is Mach number independent until vanes choke [19].…”

Section: Introductionmentioning

confidence: 99%

“…2. A detailed description of the StreamVane method is presented by Hoopes [13] and Guimarães et al [17].…”

Section: Introductionmentioning

confidence: 99%

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Complex Flow Generation and Development in a Full-Scale Turbofan Inlet

Guimarães

Lowe

O’Brien

2018

Journal of Engineering for Gas Turbines and Power

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The future of aviation relies on the integration of airframe and propulsion systems to improve aerodynamic performance and efficiency of aircraft, bringing design challenges, such as the ingestion of nonuniform flows by turbofan engines. In this work, we describe the behavior of a complex distorted inflow in a full-scale engine rig. The distortion, as in engines on a hybrid wing body (HWB) type of aircraft, is generated by a 21-in diameter StreamVane, an array of vanes that produce prescribed secondary flow distributions. Data are acquired using stereoscopic particle image velocimetry (PIV) at three measurement planes along the inlet of the research engine (Reynolds number of 2.4 × 106). A vortex dynamics-based model, named StreamFlow, is used to predict the mean secondary flow development based on the experimental data. The mean velocity profiles show that, as flow develops axially, the vortex present in the profile migrates clockwise, opposite to the rotation of the fan, and toward the spinner of the engine. The turbulent stresses indicate that the center of the vortex meanders around a preferred location, which tightens as flow gets closer to the fan, yielding a smaller radius mean vortex near the fan. Signature features of the distortion device are observed in the velocity gradients, showing the wakes generated by the distortion screen vanes in the flow. The results obtained shed light onto the aerodynamics of swirling flows representative of distorted turbofan inlets, while further advancing the understanding of the complex vane technology presented herein for advanced ground testing.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…2. A detailed description of the StreamVane method is presented by Hoopes [13] and Guimarães et al [17].…”

Section: Introductionmentioning

confidence: 99%

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Complex Flow Generation and Development in a Full-Scale Turbofan Inlet

Guimarães

Lowe

O’Brien

2018

Journal of Engineering for Gas Turbines and Power

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“…This nonuniform flow developed in a straight connecting duct before being ingested by the turbofan. The StreamVane method has been previously proven to accurately generate specific swirl distortion for both wind tunnel [18] and turbofan engine [19][20][21] testing. To mitigate the risk of stalling/surging the fan compression system under the distorted flow conditions, the fan speed was limited to 65% design maximum, corresponding to an inlet mass flow rate of approximately 45 lbm/s (20 kg/s) and fan inlet Mach number of approximately 0.3.…”

Section: Experimental Methodsmentioning

confidence: 99%

Experimental Quantification of Fan Rotor Effects on Inlet Swirl Using Swirl Distortion Descriptors

Frohnapfel

Lowe

O’Brien

2018

Journal of Engineering for Gas Turbines and Power

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The prominence of highly integrated engine/airframe architectures in modern commercial aircraft design concepts has led to significant research efforts investigating the use of conventional turbofan engines in unconventional installations where severe inlet distortions can arise. In order to determine fan rotor capabilities for reducing or eliminating a complex inlet swirl distortion, an experimental investigation using a StreamVaneTM swirl distortion generator was conducted in a turbofan engine research platform. Three-dimensional (3D) flow data collected at two discrete planes surrounding the fan rotor indicated that the intensity of the swirl distortion was decreased by the fan rotor; however, substantial swirl distortion effects remained in the fan exit flow. Flow angle magnitudes and swirl intensity (SI) decreased by approximately 30–40% across the fan rotor, while the presence of large-scale features within the distortion profile was nearly eliminated. Secondary flow streamlines indicated that small-scale features of the distortion were less affected by the rotating component and remained coherent at the fan rotor outlet plane. These results led to the conclusion that swirl distortion survived interactions with the fan rotor, leading to off-design conditions cascading through downstream engine components.

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Vortical flow development in round ducts across scales for engine inlet applications

2019

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Turbofan engine performance depends highly on the characteristics and conditions of the inlet flow. Swirl distortions, caused by non-uniformities in flows arising from boundary layer or ground/fuselage vortex ingestion are of concern and need to be fully understood to guarantee efficiency and safety of propulsion systems. To investigate a fundamental single-vortex distortion development in a duct at different Reynolds numbers, a StreamVane distortion generating device was designed and experimentally analyzed in a small-scale low-speed wind tunnel (Re D 500 × 10 3 ) and in a full-scale engine testing rig (Re D 3 × 10 6 ). Stereoscopic particle image velocimetry was used to measure the three-component velocity fields at discrete measurement planes downstream of the distortion device. Results show that the secondary flow is generated and develops very similarly in both scales, and is mostly driven by two-dimensional (2D) vortex dynamics. Induced velocities arising from the proximity of the vortex to the duct wall causes the vortex center to convect circumferentially around the duct, in the same sense as the vortex rotation, as it travels downstream. Small-scale turbulence results show small-scale instabilities related to the development of the vortex. This work shows that the development of this vane-generated, vortex-dominated flow is largely Reynolds number independent for the covered range, so that details of similar duct-bounded flows can be analyzed in depth in small-scale experiments, decreasing development efforts and cost. arXiv:1808.07273v1 [physics.flu-dyn]

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The StreamVane Method: A New Way to Generate Swirl Distortion for Jet Engine Research

Cited by 25 publications

References 7 publications

Complex Flow Generation and Development in a Full-Scale Turbofan Inlet

Complex Flow Generation and Development in a Full-Scale Turbofan Inlet

Experimental Quantification of Fan Rotor Effects on Inlet Swirl Using Swirl Distortion Descriptors

Vortical flow development in round ducts across scales for engine inlet applications

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