Unsteady Effects of a Generic Non-Axisymmetric Endwall Contour on the Rotor of a 1½ Stage Low Speed Turbine Test Rig

Dunn, Dwain; Snedden, Glen; Backström, Theodor W. von; Mdluli, Mthobisi P.

doi:10.1115/gt2013-94961

Cited by 5 publications

(7 citation statements)

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“…The numerical rotor outlet relative velocity shows that above 95% span the difference between contoured and annular were negligible, again something not seen in previous investigations (both numerical and experimental) (17,16,14,3,4) performed on this geometry.…”

Section: Resultssupporting

confidence: 69%

“…The circumferentially averaged, time-averaged unsteady CFD results presented were compared with the circumferentially averaged, time-averaged unsteady experimental results of Dunn et al (4) as well as the five hole probe steady state results as presented in Snedden (14) . The design value was listed in the graphs for reference.…”

Section: Resultsmentioning

confidence: 99%

“…The numerical rotor relative velocity magnitude correlates well with the unsteady experimental results, where the steady state results don't capture the peak found at 25% span. As discussed in Dunn et al (4) the five hole probe was connected in such a fashion that the yaw angle was calculated by comparing the pressures of the yaw ports with respect to each other (the differential pressure transducer was connected across the yaw ports). This allowed the probe to be null-yawed into the flow to capture the rotor exit conditions more accurately, as the large variation in absolute yaw angle could be accommodated.…”

Section: Resultsmentioning

confidence: 99%

“…The geometry used for the current investigation was the same as used for the previous investigations (17,16,14,3,4) . The blade profiles used can be seen in Fig.…”

Section: Numerical Setupmentioning

confidence: 99%

“…The current investigation was aimed at determining if there were any unsteady effects that were not seen in the steady state investigation that could be detrimental to the performance of a turbine, or its downstream blade rows. Dunn et al (4) performed an experimental unsteady study and found that at design the endwall secondary flow region had been reduced in size and the fluctuations in the flow were also reduced.…”

Section: Introductionmentioning

confidence: 99%

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An unsteady numerical analysis of a generic non-axisymmetric turbine endwall in a 1½ stage turbine test rig

Dunn¹,

Backström²,

Snedden³

2015

Aeronaut.j.

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As concern for the environment increases, so does the desire to reduce emissions and improve fuel efficiency. One avenue being investigated in the aerospace industry is the reduction in losses in a gas turbine engine through endwall contouring, which has shown some promise in improving efficiency. The current investigation was aimed at investigating the unsteady effects downstream of a rotor with a non-axisymmetric endwall contour originally designed for a cascade.Previous investigations (numerical and experimental) have shown that the endwall contour improved the turbine efficiency by reducing the cross passage secondary flows. The contour however had a detrimental effect on the tip flow. The current investigation found that there were negligible unsteady differences between the annular and contoured rotor, with the average comparing well to the steady state results. It was also found that the effects at the tip were due to the experimental blades untwisting during operation.

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Section: Resultssupporting

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…The geometry used for the current investigation was the same as used for the previous investigations (17,16,14,3,4) . The blade profiles used can be seen in Fig.…”

Section: Numerical Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An unsteady numerical analysis of a generic non-axisymmetric turbine endwall in a 1½ stage turbine test rig

Dunn¹,

Backström²,

Snedden³

2015

Aeronaut.j.

View full text Add to dashboard Cite

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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

Snedden¹,

Dunn²,

Ingram

2018

Aeronaut. j.

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Non-axisymmetric endwalls in turbine stages have shown to be a robust method to improve the performance of turbines in both power generation and aero-derivative applications. Non-axisymmetric endwalls target the control of secondary flows and are designed using detailed computational fluid dynamics coupled with a variety of optimisation algorithms and utilising a number of objective functions according to the engine company or researcher's preference. These numerical predictions are often backed up by detailed measurements in linear and annular cascades and later proven in full-scale engine tests. Relatively little literature is available describing their performance in rotating test rigs or at conditions other than design, apart from that of the authors. This study comprehensively revisits the low-speed, model turbines used in the earlier study, replacing all of the 5-hole probe data with more accurate results and additional hot-film measurements. These results together with computational fluid dynamics solutions are used to show the success of the method across a large incidence range and to compare to earlier cascade results for a similar endwall and blade profile to establish the usefulness of cascade testing in this application. In addition, a comparison to two other off-design studies is made. Results indicate that the endwalls successfully improve the rotor total isentropic efficiency at all test conditions and that the improvement increases with increased turning in the blade row, from 0.5% to 1.8% across the incidence range. The results also compare well to the estimation of isentropic efficiency improvement that can be drawn from the cascade testing which stands at 1.55%.

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Effect of Endwall Contouring on a Transonic Turbine Blade Passage: Heat Transfer Performance

Panchal¹,

Abraham

Roy

et al. 2016

Journal of Turbomachinery

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Effect of turbine endwall contouring on its aerodynamic performance has been widely studied, but only a few studies are available in the open literature investigating its effect on heat transfer performance; especially at transonic exit Mach number conditions. In this paper, we report a study of effect of contouring on endwall heat transfer performance of a high-turning high-pressure (HP) turbine blade passage operating under transonic exit conditions. The paper describes comparison of heat transfer performance of two contoured endwall geometries, one aerodynamically optimized (AO) and the other heat transfer optimized (HTO), with a baseline, noncontoured geometry. The endwall geometries were experimentally investigated at Virginia Tech's transient, blow down, transonic linear cascade facility at three exit Mach numbers, Mex= 0.71, 0.88(design) and 0.95, for their heat transfer performance. Endwall surface temperatures were measured using infrared (IR) thermography and local heat transfer coefficient (HTC) values were calculated using measured temperatures. A camera matrix model-based data postprocessing technique was developed to relate the two-dimensional images captured by IR camera to three-dimensional endwall contours. The measurement technique and the methodology for postprocessing of the heat transfer coefficient data have been presented in detail. Discussion and interpretation of experimental results have been augmented using aerodynamic CFD simulations of the geometries. Both the contoured endwalls demonstrated a significant reduction in the overall average heat transfer coefficient values of the order of 10%. The surface Stanton number distributions also indicated a reduction in the level of hot spots for most of the endwall surface. However, at some locations an increase was also observed, especially in the area near the leading edge (LE). The results indicate that the endwall contouring could significantly improve heat transfer performance of turbine passages.

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Unsteady Effects of a Generic Non-Axisymmetric Endwall Contour on the Rotor of a 1½ Stage Low Speed Turbine Test Rig

Cited by 5 publications

References 0 publications

An unsteady numerical analysis of a generic non-axisymmetric turbine endwall in a 1½ stage turbine test rig

An unsteady numerical analysis of a generic non-axisymmetric turbine endwall in a 1½ stage turbine test rig

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

Effect of Endwall Contouring on a Transonic Turbine Blade Passage: Heat Transfer Performance

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