An Experimental Study of Using Vortex Generators As Tip Leakage Flow Interrupters in an Axial Flow Turbine Stage

Andichamy, Veerandra C.; Khokhar, Gohar T.; Camcı, Cengiz

doi:10.1115/gt2018-76994

Cited by 8 publications

(4 citation statements)

References 17 publications

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“…Results showed that it is difficult for the ACL to have a satisfactory inhibitory effect on TLV cavitation, and once the vortex generators are not operating under design conditions, a more intense level of cavitation will be induced. 137,176 A recent numerical study by Kadivar et al 177 proposed a new type of VG called cavitating bubble generators (CGs) (Fig. 19).…”

Section: Physics Of Fluidsmentioning

confidence: 99%

Cavitation control using passive flow control techniques

et al. 2021

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Passive flow control techniques, and particularly vortex generators have been used successfully in a broad range of aero-and hydrodynamics applications to alter the characteristics of boundary layer separation. This study aims to review how such techniques can mitigate the extent and impact of cavitation in incompressible flows. This review focuses first on vortex generators to characterize key physical principles. It then considers the complete range of passive flow control technologies, including surface conditioning and roughness, geometry modification, grooves, discharge, injection, obstacles, vortex generators, and bubble generators. The passive flow control techniques reviewed typically delay and suppress boundary layer separation by decreasing the pressure gradient at the separation point. The literature also identifies streamwise vortices that result in the transfer of momentum from the free stream to near-wall low energy flow regions. The area of interest concerns hydraulic machinery, whose performance and life span are particularly susceptible to cavitation. The impact on performance includes a reduction in efficiency and fluctuations in discharge pressure and flow, while cavitation can greatly increase wear of bearings, wearing rings, seals, and impeller surfaces due to excessive vibration and surface erosion. In that context, few studies have also shown the positive effects that passive controls can have on the hydraulic performance of centrifugal pumps, such as total head and efficiency. It is conceivable that a new generation of design in hydraulic systems may be possible if simple design features can be conceived to maximize power transfer and minimize losses and cavitation. There are still, however, significant research gaps in understanding a range of impact factors such as manufacturing processes, lifetime, and durability, and essentially how a static design can be optimized to deliver improved performance over a realistic range of operating conditions.

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Section: Physics Of Fluidsmentioning

confidence: 99%

Cavitation control using passive flow control techniques

et al. 2021

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“…13 Tip clearance and the number of blades in a propeller are additional design considerations that impact performance. [14][15][16][17][18][19][20][21][22][23][24] The use of ducts is then limited in certain circumstances, researchers aim in this case to improve the performance of the propeller system otherwise. Optimizing propeller shape, including chord length, pitch angle, twist, sweep, and lean, is crucial for efficient and highperformance propellers.…”

Section: Introductionmentioning

confidence: 99%

The impact of curved-tip propeller geometry on hovering drone performance for air quality monitoring

Chakchouk,

El Hami,

Dahoo

et al. 2023

Advances in Mechanical Engineering

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The success or failure of a drone mission depend on several elements, including the drone’s mass and payload, the surrounding environment, the battery’s state, and the propulsion system’s performance. Several studies have been undertaken addressing the propeller performance of this final component, particularly for fixed-wing or quad copter drones with ducted propellers. However, the shape of propeller blades used on tiny civil drones has not drawn as much attention. In this research work, the performance characteristics of a 10 × 4.7-inch curved tip propeller were explored, with the Advanced Precision Composite drone propeller serving as a design reference. This study seeks an alternative to ducted propellers when mass or size limitations prevent their use. The Computational Fluid Dynamics model was confirmed by comparing simulation results to the experimental propeller data source established by the University of Illinois at Urbana-Champaign, starting with a standard type propeller and using thrust coefficient as the key performance indicator. Moreover, the data analysis for the bended tip propeller replicating the well-established model, revealed the benefits as well as the drawbacks of such propellers on the mission profile and the battery lifespan of a quad copter Unmanned Air Vehicle.

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“…and suction side (S.S.), overtip leakage (OTL) generates in the tip gap, resulting in pronounced aerodynamic loss and increased thermal load in the tip region of high pressure (HP) gas turbine stage. 1 To reduce the thermal load and improve the aerodynamic performance in blade tip region, many innovative tip designs and advanced cooling schemes have been presented in the modern gas turbine community 2 In HP turbine stages, the squealer tips are commonly applied due to their superior aerodynamic performance and relatively low thermal load as compared with the flat tips. 1 Evidences have shown that the P.S.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigations into heat transfer and film cooling effect on winglet-squealer tips in a turbine stage

Yan

Huang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Heat transfer and film cooling effect on three kinds of winglet-squealer tips (i.e. conventional squealer tip, no P.S. rim tip and P.S. winglet tip) in a turbine stage are numerically investigated at two operation conditions (i.e. laboratory testing condition and sea-level take-off condition) and three cooling-hole arrangements (i.e. un-cooled, with tip holes, and with both tip and pressure side holes), and the numerical results are also compared with those in stationary cascades. To reduce the heat transfer while enhancing film cooling effect on the P.S. winglet tip, ejection angles for the tip and pressure side cooling holes are varied to reveal the superior performance of P.S. winglet tip in turbine stage. The results show that the heat transfer coefficient and film cooling effectiveness distributions on three kinds of tips exhibit different trends in the stationary and rotating cases. Tip rotating significantly affects the trajectories of cooling flow in the conventional squealer tip and no P.S. rim tip due to different vortex system induced in the cavity. However, the relative rotating has little influence on the flow structures in the P.S. winglet tip. In un-cooled condition, the area-averaged heat transfer coefficient on P.S. winglet tip is lower than the conventional squealer tip by 11.6%. For the vertical ejection case in turbine stage, the P.S. winglet tip has a slightly worse heat transfer and film cooling effect than the conventional squealer tip. However, with inclined ejections, the area-averaged heat transfer coefficient on winglet tip in turbine stage is lower than the conventional squealer tip by 15.3%, and the area-averaged film cooling effectiveness on winglet tip is higher than the conventional squealer tip by 12.1%.

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An Experimental Study of Using Vortex Generators As Tip Leakage Flow Interrupters in an Axial Flow Turbine Stage

Cited by 8 publications

References 17 publications

Cavitation control using passive flow control techniques

Cavitation control using passive flow control techniques

The impact of curved-tip propeller geometry on hovering drone performance for air quality monitoring

Investigations into heat transfer and film cooling effect on winglet-squealer tips in a turbine stage

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