Boundary Layer Control of an Axial Compressor Cascade Using Nonconventional Vortex Generators

Diaa, Ahmed M.; El-Dosoky, M.F.; Ahmed, Mahmoud; Abdel-Hafez, Omar E.

doi:10.1115/imece2015-52310

Cited by 8 publications

(3 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diaa et al. 29,30 numerically simulated a novel design of vortex generator at design and off-design conditions, achieving a maximum loss coefficient reduction by 20.7%. Li et al.…”

Section: Introductionmentioning

confidence: 99%

Performance enhancing for a highly loaded tandem cascade by endwall incoming vortex–corner separation interaction

Cao

Gao

Song

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

View full text Add to dashboard Cite

In highly loaded tandem compressor cascades, corner separations can still exist. In order to eliminate corner separations in highly loaded tandem compressor cascades, incoming vortex–corner separation interaction mechanism was investigated. Different schemes of the vortex generators, which located at different pitchwise locations and could generate vortexes with different rotation directions, were designed and investigated numerically. Results show that, severe corner separation occurred at the front blade passage of the tandem cascade; by utilizing flow control method of incoming vortex–corner separation interaction, the corner separation could be reduced significantly. The optimal control effect of incoming vortex on corner separation was achieved with anticlockwise rotation and the vortex generator is located right ahead of the leading edge of tandem cascade, a maximum loss coefficient reduction of 21.8% being achieved. Different from single blade configuration, the boundary layer of tandem cascade was regenerated at rear blade suction surface due to the injection flow from blade gap between the two blades. Though corner separations could be reduced at both conditions, the loss of tandem cascade with clockwise incoming vortex is higher than that with anticlockwise vortex, and a smaller corner separation region at suction surface was achieved by utilizing clockwise vortex. The mechanism was that anticlockwise incoming vortex reduced the corner separation but increased secondary flow, while clockwise vortex enhanced passage vortex and decreased secondary flow. For clockwise incoming vortex near pressure surface, the vortex would be divided into two parts at the leading edge of rear blade, one would go through the blade gap and deteriorate flow fluid near rear blade suction surface, the other flowed downstream along pressure surface. The rotation direction of different incoming vortexes became the same as the passage vortex at rear blade passage of tandem cascade, which was mainly due to the effect of secondary flow.

show abstract

“…Diaa et al. 29,30 numerically simulated a novel design of vortex generator at design and off-design conditions, achieving a maximum loss coefficient reduction by 20.7%. Li et al.…”

Section: Introductionmentioning

confidence: 99%

Performance enhancing for a highly loaded tandem cascade by endwall incoming vortex–corner separation interaction

Cao

Gao

Song

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

View full text Add to dashboard Cite

show abstract

“…Passive flow control of endwall loss is currently employed via shaping: endwall fence/groove (Hage and Paschereit 2007), vortex generator (Diaa et al 2015), endwall contouring (Chen et al 2012), casing treatment, etc, which is beneficial to delay or provoke separation. As a structural bulge along streamwise on endwall surface, endwall fence is available to hinder the crossflow and generate the fence vortex (Liu et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Control 0f Secondary Crossflow in a High-Speed Compressor Cascade by Endwall Fences with Varying Locations

Chen¹,

Yang²,

Zhong³

2019

Proceedings of Global Power &Amp; Propulsion Society

View full text Add to dashboard Cite

It is well known that the secondary flow, including vortexes, boundary layer, and three-dimensional separation, is detrimental to the efficiency and stability in the axial compressor. As a passive secondary flow control technique, the endwall fence is considered to overcome the adverse pressure gradient by blocking the crossflow. On this paper, a steady computational study is carried out in a high-speed compressor cascade. Two categories of fence configurations, i.e., embedded in the front and the back of flow passage, have been investigated. For each category, the fence position is selected at 7 locations ranging from 20% to 80% pitch length away from the blade pressure surface, the interval between each case is 10% pitch length. In the comparison between the datum and the fenced cascade, the case of 50% pitch length away from the blade suction surface in the category of front fences is most effective in the improvement of the aerodynamic performance. At the design point, this case decreases the loss coefficient and the blockage coefficient by 6.3% and 6.5%, respectively. Meanwhile, it increases the absolute value of the flow turning angle by 0.9%. From the perspective of the vortex structure, both optimum fences in the front and back category can suppress the passage vortex by inducing the counter-rotating fence vortex, of which scale has a relationship with the contact area between fence surface and the crossflow. Last but not least, the fenced cascade with an optimum performance both in loss mechanism and vortex structure has been investigated under varying inlet incidences. The comparison analysis of the baseline and optimum fence and demonstrates that there is a reduction of the loss exists at negative incidences while an augment occurs at positive incidences. In summary, the optimum case of endwall fence can effectively weaken the endwall loss and thereby enlarge the cascade operating range under negative incidences.

show abstract

“…However the static pressure rise due to inserting a vortex generator was nearly unaffected. Diaa et al [28][29] have investigated the effect of the curved side vortex generators as a control device with axial compressor cascade, they reported a reduction of total pressure loss of 12%. Based on the literature survey of the research work related to the current subject, the suggested curved surface design of vortex generator is inspired from Wheeler's doublet VG [30] that was used in several applications on flat plates.…”

Section: Introductionmentioning

confidence: 99%

Effect of a New Vortex Generator on the Performance of an Axial Compressor Cascade at Design and Off-Design Conditions

Diaa

El-Dosoky

Ahmed

et al. 2015

Volume 1: Advances in Aerospace Technology

Self Cite

View full text Add to dashboard Cite

Secondary flows are noxious to axial compressor performance. To overcome and control those secondary flows, vortex generators are used as a passive control device. Controlling secondary flows will lead to a further improvements in the compressor performance. A new design of vortex generator is considered in this investigation in order to control secondary flows in axial compressor cascade at design and off-design conditions. Numerical simulations of a three-dimensional compressible turbulent flow have been performed to explore the effect of the vortex generators on the reduction of secondary flows. Six different incidence angles are used for the off-design operation investigations. Based on the simulation results, the pressure, velocity, and streamline are used to follow up the development of the secondary flows. Thence, total pressure loss coefficient, static pressure rise coefficient, difference in flow deflection angle, and diffusion factor are estimated. Results indicate that vortex generators have a significant effect on the development of secondary flows at off design operation as they cause a reduction in total pressure loss, they also affect the loading behavior of the cascade as they cause a slight change in the cascade deflection, and a slight decrease in the diffusion factor which causes unloading of the blade. Static pressure rise is significantly reduced at negative incidence angles while a slight reduction occurs at positive incidence angles. In a word, the new design of the vortex generator enhances the cascade aerodynamic performance and enlarges the operating range of the cascade towards the positive incidence region.

show abstract

Boundary Layer Control of an Axial Compressor Cascade Using Nonconventional Vortex Generators

Cited by 8 publications

References 20 publications

Performance enhancing for a highly loaded tandem cascade by endwall incoming vortex–corner separation interaction

Performance enhancing for a highly loaded tandem cascade by endwall incoming vortex–corner separation interaction

Control 0f Secondary Crossflow in a High-Speed Compressor Cascade by Endwall Fences with Varying Locations

Effect of a New Vortex Generator on the Performance of an Axial Compressor Cascade at Design and Off-Design Conditions

Contact Info

Product

Resources

About