The impact of volute aspect ratio and tilt on the performance of a mixed flow turbine

Lee, Samuel P.; Barrans, Simon; Nickson, A.K.

doi:10.1177/0957650921998228

Cited by 7 publications

(8 citation statements)

References 23 publications

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“…But at 180°and 210°, the secondary flows in Case 1 volute become weaker than that in the baseline volute. This is consistent with the results in Cerdoun and Ghenaiet 11 and Lee et al 13,14 Because of the increasing influence from the discharging flows, the secondary flows in volute with narrow cross-sections disappear quickly at large azimuthal angles. The baseline volute has the strongest secondary flows at 180°and 210°, this is mainly because its circular cross-sectional shape.…”

Section: Impacts Of Volute Cross-sectional Shapessupporting

confidence: 92%

Secondary flows and losses in radial turbine volutes

Chen

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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Secondary flows had been found in radial turbine volutes in the past, but the flow mechanisms governing their existence are far from clear. This paper describes an analytic and numerical work on the mechanism of the secondary flows, and the effects of volute shape, A/R distribution, and turbine speed on the development and associated losses of the secondary flows in the turbine volutes. The results show that the centrifugal and viscous forces acting on the wall boundary-layer, as well as the diffusion of radial flow in volute’s cross-sections, are the main generating mechanism of secondary flows, but they are worked against by volute discharging. Compared with the rectangular and trapezoidal shape volutes, the circular volute generates stronger secondary flows, resulting in no hydrodynamic benefit over the other two volutes. By using the dissipation function to separate the secondary flow loss from the total loss in the three volutes, it shows for the first time that although the loss from secondary flows alone is small, the flows can push the main flows toward volute side walls thereby increase wall friction loss. Three twin-entry volutes with different aspect ratios of their cross-sections are also studied. The offset of the cross-section center to volute exit affects volute discharging and the aspect ratio impacts on the radial flow in sidewall boundary layers, they therefore influence the secondary flows in the volutes. The slope of A/R curves is found to correlate well to the strength of the secondary flows in the volutes, and the reason behind is explained. Turbine speed’s influence on the secondary flows is largely through flow compressibility, and if the speed change reduces turbine inlet Mach number, it will increase discharge flow angle at the volute exit, and so too the strength of the secondary flows, but the changes will be small.

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Section: Impacts Of Volute Cross-sectional Shapessupporting

confidence: 92%

Secondary flows and losses in radial turbine volutes

Chen

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…Hamel et al [4] investigated a twin entry flow turbine volute. In papers [5][6][7] presented the aerodynamic performance of the mixed flow turbine blade design. Bencherif et al [8] studied the unsteady performance of a twin-entry mixed flow turbine.…”

Section: Literature Reviewmentioning

confidence: 99%

Analysis of the Three-Dimensional Accelerating Flow in A Mixed Turbine Rotor

Chelabi¹,

Basova²,

Hamidou³

et al. 2021

JES

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An investigation on new rotor blade designs conceived to produce higher exit relative kinetic energy of a mixed flow turbine is undertaken. Accelerating the flow through the rotor in a relative frame of reference improves energy transfer to the shaft, which is only produced in a rotating rotor. A three-dimensional converging rotor channel might respond to the analysis requirements in the subsonic flow regimes. Effectively, the machine experiences a 3.71 % and 3.67 % increase in work output and efficiency, respectively, representing this study’s primary intent. This has been accomplished by varying the shroud profile to a lesser eye tip diameter, then the hub profile to a larger eye root diameter. At last, both shroud and hub profiles are varied. It appears possible to enhance the performance of the rotor in terms of optimum work done and efficiency by devising suitable blade geometry designs. ANSYS CFX 15 is the code of all simulation works.

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“…Dean vortices, which were first reported by Dean, 9,10 have been found in the turbine volutes. 11–13 The Dean vortices are caused by an imbalance between centrifugal force and the radial pressure gradient. Cerdoun and Ghenaiet 11 conducted a numerical study to characterize the flow of a twin entry radial turbine and the development of Dean vortices in its asymmetrical volute.…”

Section: Introductionmentioning

confidence: 99%

“…They modified the volute by increasing the A/R of the hub side volute and decreasing the A/R of the shroud side volute, and then the Dean vortices disappeared in the modified volute. Lee et al 12,13 studied the impact of volute aspect ratio and tilt on the performance of a mixed flow turbine. Their results showed that the aspect ratio of the volute has a significant effect on the development of the secondary flow within the volute.…”

Section: Introductionmentioning

confidence: 99%

Application of an extended two-dimensional inverse method in turbine volute design

Li¹,

Wang²,

Chen³

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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Nozzleless housings for turbocharger turbines accelerate and guide flow into downstream rotors. Their design affects the aerodynamic performance and reliability of the turbines. Due to the three-dimensional nature of the volute of the housings, turbine housing volute design is largely based on extended 1D theories and trial-and-error method. In this paper, a detailed description of an extended two-dimensional theory for volute design is given, including its numerical implementation. The method is then applied to design a twin-entry turbine housing for a turbocharger turbine under both equal and unequal admissions, to replace a highly optimized, manually designed housing. The results show that the new volute achieves the same turbine aerodynamic performance as the manually optimized volute with greatly reduced design time, and it also generates more uniform rotor inlet condition with lower pressure excitation force. A breakdown of the stage loss shows that the loss in the new volute housing is larger than that in the manual housing due to its smaller overall dimensions, but the losses inside rotor and downstream diffuser are both reduced due to the more uniform volute exit flow. A discussion on the secondary flow in the two volutes is carried out to show how the volute geometry, through influencing the radial discharge from the volute exit, affects this flow. A further discussion on the flow angle jump around the tongue is placed at the end of the paper to show the mechanism of this jump, how to control it in volute design, and to offer a way forward to improve the volute design method.

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The impact of volute aspect ratio and tilt on the performance of a mixed flow turbine

Cited by 7 publications

References 23 publications

Secondary flows and losses in radial turbine volutes

Secondary flows and losses in radial turbine volutes

Analysis of the Three-Dimensional Accelerating Flow in A Mixed Turbine Rotor

Application of an extended two-dimensional inverse method in turbine volute design

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