A review of flow control techniques and optimisation in s-shaped ducts

Wojewodka, Michael M.; White, Craig; Shahpar, Shahrokh; Kontis, Konstantinos

doi:10.1016/j.ijheatfluidflow.2018.06.016

Cited by 30 publications

(7 citation statements)

References 61 publications

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“…The L/D ratio of the S-duct is 5 and the diffusion area ratio of A throat /A exit is 0.8. The duct was connected to two straight sections, one at the inlet and other at the outlet, that help with the development of the boundary layer at the inlet and to align the flow to the engine axis at the exit [9,10]. The exit of the duct was connected to a 50 JM Maxfan 2-stage axial fan with dynamic speed control.…”

Section: A Constant Pressure Inside a Plenum Chamber With Constant In...mentioning

confidence: 99%

Characterization of a Low Profile, Rapidly Deployable, MEMS Pressure Sensor Array for Aerodynamic Applications.

Subramanian

Hampson

Zhang

et al. 2022

AIAA SCITECH 2022 Forum

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Section: A Constant Pressure Inside a Plenum Chamber With Constant In...mentioning

confidence: 99%

Characterization of a Low Profile, Rapidly Deployable, MEMS Pressure Sensor Array for Aerodynamic Applications.

Subramanian

Hampson

Zhang

et al. 2022

AIAA SCITECH 2022 Forum

Self Cite

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“…On the other hand, hybrid systems can have an additional benefit on performance parameters, compared to passive or active flow control alone [41]. As to mixing the mainstream and the secondary flow, some passive flow control technology, such as the vortex generator, shows great potential [42][43][44][45][46][47].…”

Section: Additional Improvement For the Original Suction Controlmentioning

confidence: 99%

Suction Control of a Boundary Layer Ingestion Inlet

Liu,

Li,

Wang

et al. 2023

Aerospace

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This study presents a numerical investigation of suction control in an aggressive S-shaped air intake with large boundary ingestion. The results show that the variation of suction control parameters such as suction location, suction pipe diameter, and suction angle all have an impact on the effectiveness of the flow control. In general, further upstream suction, such as near the throat, is favorable for the decrease of the second flow intensity and the area of the low-energy fluid region at the exit of the S-shaped inlet. However, it is bad for the total pressure recovery and the circumferential total pressure uniform distribution. From the perspective of the uniformity of the total pressure distribution at the air intake exit, there is an optimal location for suction between the throat and the separation start point. A bigger suction pipe diameter brings better effects as the suction location and suction angle keep constant, due to more low-energy fluid being sucked out. But this doesn’t mean the largest mass flow suction results in the biggest improvement. Overall, sucking at the 1st bend, with suction angle and suction pipe diameter equaling 15 degrees and 12 mm, respectively, is the optimal suction scheme here. Since the change rule of the cross-section area along the centerline has not changed during suction control, the second flow and complex surface streamline at the air intake exit cannot be eliminated, though they can be decreased a lot with reasonable suction control. Similarly, owing to large boundary ingestion, the remarkable low-energy fluid region always exists despite the significant reduction of the separation and second flow, which is very different from the results of this kind of micro-suction executed in the non-BLI S-duct. To pursue a higher improvement, suction combined with vortex generator vanes has been further studied. Corresponding results analysis shows that the hybrid flow control method has great potential and should be investigated in detail in the future.

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“…Most of the research focused on the use of inlet vortex generators as flow control devices to reduce the separations within the intake, the strength of the secondary flows and, consequently the engine fan face distortion. [38][39][40] For example, a study on the reduction of the unsteadiness of the peak swirl with sub-boundary layer vortex generators was conducted by Tanguy et al 41 Research focused also on methods to generate vortices for engine inlet applications and on the vortex development from the source (i.e. ground vortex or wingtip vortex) to the intake.…”

Section: Introductionmentioning

confidence: 99%

S-duct flow distortion with non-uniform inlet conditions

Migliorini

Zachos

MacManus

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Convoluted aero-engine intakes are often required to enable closer integration between engine and airframe. Although the majority of previous research focused on the distortion of S-duct intakes with undistorted inlet conditions, there is a need to investigate the impact of more challenging inlet conditions at which the intake duct is expected to operate. The impact of inlet vortices and total pressure profiles on the inherent unsteady flow distortion of an S-duct intake was assessed with stereo particle image velocimetry. Inlet vortices disrupted the characteristic flow switching mode but had a modest impact on the peak levels and unsteady fluctuations. Non-uniform inlet total pressure profiles increased the peak swirl intensity and its unsteadiness. The frequency of swirl angle fluctuations was sensitive to the azimuthal orientation of the non-uniform total pressure distribution. The modelling of peak distortion with the extreme value theory revealed that although for some inlet configurations the measured peak swirl intensity was similar, the growth rate of the peak values beyond the experimental observations was substantially different and it was related with the measured flow unsteadiness. This highlights the need of unsteady swirl distortion measurements and the use of statistical models to assess the time-invariant peak distortion levels. Overall, the work shows it is vital to include the effect of the inlet flow conditions as it substantially alters the characteristics of the complex intake flow distortion.

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A review of flow control techniques and optimisation in s-shaped ducts

Cited by 30 publications

References 61 publications

Characterization of a Low Profile, Rapidly Deployable, MEMS Pressure Sensor Array for Aerodynamic Applications.

Characterization of a Low Profile, Rapidly Deployable, MEMS Pressure Sensor Array for Aerodynamic Applications.

Suction Control of a Boundary Layer Ingestion Inlet

S-duct flow distortion with non-uniform inlet conditions

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