Highly Loaded Low-Pressure Turbine: Design, Numerical, and Experimental Analysis

Schmitz, John T.; Perez, Ethan; Morris, Scott; Corke, Thomas; Clark, John P.; Koch, Peter; Puterbaugh, Steven L.

doi:10.2514/1.b35334

Cited by 16 publications

(6 citation statements)

References 15 publications

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“…The POD was utilized as a filter to remove high-frequency "noise" and thus improve the quality of the phase-averaged data. Towards that end, the phase-averaged flow field was reconstructed from the leading POD modes based on Equation (24). For all cases, only the downstream blocks 1, 6, 7, and 8 were processed.…”

Section: Proper Orthogonal Decomposition Of Phase-averaged Flowmentioning

confidence: 99%

“…Annular cascades more closely represent the unsteady flow in turbine engines. Such systems, however, are complicated, expensive and difficult to instrument [24]. In linear cascade experiments, two-dimensional (2-D) wakes without pronounced secondary flow can be generated with moving-bar wake generators.…”

Section: Introductionmentioning

confidence: 99%

“…Experiments by Volino [37] revealed a complete suppression of laminar separation for high wake passing frequencies and an intermittent suppression of flow separation for low wake passing frequencies. Experiments by Schmitz et al [24] considered a single stage rotating rig with transonic LPT blades. Observed inconsistencies of the endwall data led to the conclusion that a need exists for models that accurately capture the secondary flow effects and the endwall losses.…”

Section: Introductionmentioning

confidence: 99%

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Large-Eddy Simulation of Low-Pressure Turbine Cascade with Unsteady Wakes

Robison

Groß

2021

Aerospace

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To better understand the wake effects at low Reynolds numbers, large-eddy simulations of a 50% reaction low-pressure turbine stage and a linear cascade with two different bar wake generators were carried out for a chord Reynolds number of 50,000. For the chosen front-loaded high-lift airfoil, the endwall structures are stronger than for more traditional mid-loaded moderate-lift airfoils. By comparing the 50% reaction stage results with the bar wake generator results, insight is gained into the effect of the three-dimensional wake components on the downstream flow field.For the cases with bar wake generator, the endwall boundary layer is growing faster because of the relative motion of the endwall with respect to the freestream. The half-width of the wake is approximately matched for the larger one of the two considered bar wake generators. To improve the quality of the phase-averaged flow fields, the proper orthogonal decomposition was employed as a filter to remove the low-energy unsteady flow field content. Both the mean flow and filtered phase-averaged flow fields were analyzed in detail. Visualizations of the phase-averaged flow field reveal a periodic suppression of the laminar suction side separation from the downstream airfoil even for the smaller bar wake generator. The passage vortex is entirely suppressed for the 50% reaction stage and for the larger bar wake generator. Furthermore, the phase-averaged data for the 50% reaction stage reveal a new longitudinal flow structure that is traced back to near-wall wake vorticity. This flow structure is missing for the bar wake generator cases.

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Section: Proper Orthogonal Decomposition Of Phase-averaged Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large-Eddy Simulation of Low-Pressure Turbine Cascade with Unsteady Wakes

Robison

Groß

2021

Aerospace

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“…Two key design parameters that drive weight and part count are the work output per stage and the blade loading coefficient. These two parameters can be manipulated during design to impact the footprint and the performance of the LP turbine section by increasing the loading of each blade [3].…”

Section: Introductionmentioning

confidence: 99%

“…Each of these phenomena pose a challenge to numerical design tools. The design and subsequent verification in a high-speed rotating turbine facility of a highly loaded LPT is described in Schmitz et al [3]. The design process included the use of three-dimensional unsteady Reynolds-averaged Navier-Stokes (RANS).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Endwall Loss Reduction Techniques in a High-Lift Turbine Passage

Marks

Fletcher

Sondergaard

2021

Journal of Turbomachinery

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The development of techniques that reduce the losses in the endwall region is an important area of research as it supports an increase in the turbine design space through the use of higher lift blade designs while maintaining high efficiency. Several active and passive shape contouring methods that reduce losses generated by the secondary flow have been developed and investigated on a high-lift front-loaded LP turbine research profile in a low-speed linear cascade configuration. This paper summarizes and compares alterations to the three-dimensional secondary flow field by the application of three different techniques: blade profile contouring, optimized endwall shape contouring, and localized low mass coefficient jets. Each method was applied to identical research blade profiles and compared in the same linear cascade wind tunnel resulting in a unique perspective into the loss reduction mechanisms associated with each technique. The design strategy will be discussed along with a detailed description of changes to the secondary flow field using in- and out-of-passage total pressure loss measurements and high-speed stereoscopic particle image velocimetry. The key findings include the loss reduction mechanisms associated with each approach and the manipulation of key endwall flow structures such as the passage vortex and a strong suction surface corner separation.

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Generation of unsteady incoming wakes for wake/blade interaction

Wei

Gan

et al. 2020

Aerospace Science and Technology

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Highly Loaded Low-Pressure Turbine: Design, Numerical, and Experimental Analysis

Cited by 16 publications

References 15 publications

Large-Eddy Simulation of Low-Pressure Turbine Cascade with Unsteady Wakes

Large-Eddy Simulation of Low-Pressure Turbine Cascade with Unsteady Wakes

Comparison of Endwall Loss Reduction Techniques in a High-Lift Turbine Passage

Generation of unsteady incoming wakes for wake/blade interaction

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