On- and off-design performance of a model rotating turbine with non-axisymmetric endwall contouring and a comparison to cascade data

Snedden, Glen; Dunn, Dwain; Ingram, Grant

doi:10.1017/aer.2018.13

Cited by 2 publications

(2 citation statements)

References 36 publications

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“…The influence of the NEW was extended by approximately 10% from the hub. The reduction of the C SKE is used as a measure of the effectiveness of the endwall optimization [29]. Unlike subsonic turbines, C SKE was of a conflicting nature with the performance parameter of the efficiency.…”

Section: Optimization Of the Stator Hubmentioning

confidence: 99%

Secondary Flow and Endwall Optimization of a Transonic Turbine

2019

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A detailed numerical analysis of secondary flows in a transonic turbine is presented in this paper. The turbine stage is optimized by mitigating secondary flow through the method of non-axisymmetric endwall design. An automated optimization platform of NUMECA/Design3D was coupled with Euranus as a flow solver for the numerical investigation. The contoured endwalls of the stator and the rotor hub were designed based on equidistant Bézier curves along the camber line in the blade channel. The initial design samples were ten times the number of the design variables, and were generated through the LHS method for database generation. The optimization of the endwalls was achieved by using a state-of-the-art multi-objective optimization algorithm, NSGA-II, connected with the BPNN to increase the isentropic efficiency and decrease the secondary kinetic energy, while the mass flow and the degree of reaction were constrained to remain on the datum value as in the original geometry. The individual optimization of the hub endwalls of the stator and the rotor produced an increase in the efficiency of 0.27% and 0.25%, respectively, resulting in a cumulative improvement of 0.46% in the efficiency. The increase in the performance was analyzed at part-load conditions, and it was further confirmed through unsteady simulations.

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Section: Optimization Of the Stator Hubmentioning

confidence: 99%

Secondary Flow and Endwall Optimization of a Transonic Turbine

2019

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“…This was considered acceptable for the current work due to the low-speed nature of the rig, and for a full derivation of the quantity the reader is directed to Snedden et al. 2,37 In addition, and also due to the low pressure nature of the rig, the radial velocities (V3,rad 2) in equation (16) were taken to be any radial component in the flow, since the design velocity contained no radial component. Further, for both the Cske (equation (16)) and β dev (equation (18)) quantities, the off-axis flow velocity and angle were calculated using the design flow angle, which itself was calculated during the design of the blading using the NREC design suite 38 and represented as a function of the blade span ( S ).…”

Section: Objective Functionsmentioning

confidence: 99%

Development of an automated non-axisymmetric endwall contour design system for the rotor of a 1-stage research turbine – part 1: System design

Bergh

Snedden

Reddy

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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Secondary flows are a well-known source of loss in turbomachinery flows, contributing up to 30% of the total aerodynamic blade row loss. With the increase in pressure on aero-engine manufacturers to produce lighter, more powerful and increasingly more efficient engines, the mitigation of the losses associated with secondary flow has become significantly more important than in the past. This is because the production of secondary flow is closely related to the amount of loading and hence the work output of a blade row, which then allows part counts and overall engine weight to be reduced. Similarly, higher efficiency engines demand larger engine pressure ratios which in turn lead to reduced blade passage heights in which secondary flows then dominate. This article discusses the design and application of an automated turbine non-axisymmetric endwall contour optimization procedure for the rotor of a low speed, 1-stage research turbine, which was used as part of a research program to determine the most effective objective functions for reducing turbine secondary flows. In order to produce as effective as possible designs, the optimization procedure was coupled to a computational fluid dynamics routine with as high a degree of fidelity as possible and an efficient global optimization scheme based on the so-called efficient global optimization algorithm. In order to compliment the requirements of the efficient global optimization approach, as well as offset some of the computational requirements of the computational fluid dynamics, the DACE metamodel was used as an underlying surrogate model.

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On- and off-design performance of a model rotating turbine with non-axisymmetric endwall contouring and a comparison to cascade data

Cited by 2 publications

References 36 publications

Secondary Flow and Endwall Optimization of a Transonic Turbine

Secondary Flow and Endwall Optimization of a Transonic Turbine

Development of an automated non-axisymmetric endwall contour design system for the rotor of a 1-stage research turbine – part 1: System design

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