Effect of Nonuniform Inlet Conditions on Endwall Secondary Flows

Hermanson, Kristina S.; Thole, Karen A.

doi:10.1115/1.1505849

Cited by 28 publications

(5 citation statements)

References 19 publications

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“…Hartland et al [17]. and Chyu [18] on controlling the secondary flows using concepts such as end wall contouring; and the work by Hermanson and Thole [19] on the effects of nonuniform inlet flow conditions on secondary flows.…”

Section: Review Of Past Literaturementioning

confidence: 98%

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and End Wall Heat Transfer: An Experimental and Computational Investigation

Qureshi

Beretta

Povey

2010

Journal of Engineering for Gas Turbines and Power

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This paper presents experimental measurements and computational predictions of surface and end wall heat transfer for a high-pressure (HP) nozzle guide vane operating as part of a full HP turbine stage in an annular rotating turbine facility, with and without inlet temperature distortion (hot streaks). A detailed aerodynamic survey of the vane surface is also presented. The test turbine was the unshrouded MTI turbine, installed in the Tut bine Test Facility (previously called Isentropic Light Piston Facility) at QinetiQ, Farnborough, UK. This is a short-duration facility, which simulates engine-representative M, Re, nondimensional speed, and gas-to-wall temperature ratio at the turbine inlet. The facility has recently been upgraded to incorporate an advanced second-generation combustor simulator, capable of simulating well-defined, aggressive temperature profiles in both the radial and circumferential directions. This work forms part of the pan-European research program, TATEF ¡I. Measurements of HP vane and end wall heat transfer obtained with inlet temperature distortion are compared with results for uniform inlet conditions. Steady and unsteady computational fiuid dynamics (CFD) predictions have also been conducted on vane and end wall surfaces using the Rolls-Royce CFD code HYDRA to complement the analysis of experimental results. The heat transfer measurements presented in this paper are the first of their kind in that the temperature distortion is representative of an extreme cycle point, and was simulated with good periodicity and with well-defined boundary conditions in the test turbine.

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Section: Review Of Past Literaturementioning

confidence: 98%

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and End Wall Heat Transfer: An Experimental and Computational Investigation

Qureshi

Beretta

Povey

2010

Journal of Engineering for Gas Turbines and Power

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“…The results of an experimental campaign carried out in a large-scale low speed axial turbine presented by (Butler, et al, 1989) demonstrated the increase of secondary flows due to temperature gradients originating from temperature distortions propagating from the turbine inlet. The influence of realistic turbine nonuniform inlet conditions on secondary flows was investigated also analytically (Lakshminarayana, 1975) and computationally by (Hermanson & Thole, 2002), who highlighted the need to consider realistic stage inlet profiles, due to the influence of pressure and temperature gradients on the secondary flows intensity.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic and aeroelastic experimental investigation on the propagation of inlet temperature distortions in a low pressure turbine stage

Simonassi,

Zenz,

Pramstrahler

et al. 2021

European Conference on Turbomachinery Fluid Dynamics and Thermodynamics

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The inlet conditions of modern low pressure turbine (LPT) present significant flow nonhomogeneities, which can have direct consequences on both its aerodynamic performance and vibrations. The rise in turbine entry temperatures and pressure ratios needed to achieve higher efficiencies and power output requires an increase of cooling and purge flow injections, leading to the generation of strong temperature distortions at the inlet of the LPT. Additionally, the stronger interaction between engine components due to the drastic decrease of axial spacing and to the reduction of the stage count facilitates the propagation of circumferential distortions of total pressure and temperature.This paper reports on the results of an experimental investigation focused on total temperature distortions at the inlet of a modern low pressure turbine stage and on the propagation of such inflow disturbances through the stage, with a particular focus on both the aerodynamic and aero-elastic performance of the turbine. The measurement activity was carried out in a one and a half stage subsonic turbine test facility at the Institute of Thermal Turbomachinery and Machine Dynamics at Graz University of Technology at an engine relevant operating condition. Total temperature distortions with different intensities were generated upstream of the stage through the localised injection of air at different mass flow and temperature, ranging from 30% to 130% of the nominal inlet temperature. A setup with clean inflow was additionally used as reference. Aerodynamic measurements were taken upstream of the investigated stage by means of a five-hole-probe (5HP). The rotor blade vibration data was acquired with strain gauges applied on different blades, in combination with a telemetry system.The rotor vibrations were influenced by the alterations created by the circumferential temperature perturbation in the flow. In particular, the temperature of the distortion was found to influence directly the amplitude of the rotor blade forced response. Therefore, important aerodynamic and aero-elastic effects were linked to the presence of total temperature distortions in the inlet flow field of an LPT stage.

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“…That effect was attributed to the increase in the secondary flow due to temperature gradients. The impact on vorticity production due to temperature non-uniformities was early investigated analytically by Lakshminarayana 12 and later computationally by Hermanson and Thole 13 who showed that zero streamwise vorticity is produced through a turbine stator blade passage when stagnation temperature distortion is not accompanied by gradients in Mach number and stagnation pressure. The results of Hermanson and Thole demonstrated the need to consider more realistic turbine inlet profiles in the simulations due to the effect of pressure gradient on the magnitude of secondary flows.…”

Section: Introductionmentioning

confidence: 99%

Full annulus numerical study of hot streaks propagation in a hydrogen-rich syngas-fired heavy duty axial turbine

Ioannou

Sayma

2017

Proceedings of the Institution of Mechanical Engineers, Part A:

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract This paper presents a study of the effect of fuel composition on hot streaks propagation in a high-pressure turbine using a full annulus unsteady CFD analysis of the first two stages. Hot streaks result from the inherent no-uniformities of temperature profiles at the exit of the combustion chamber. Variations in composition arise from current challenges requiring gas turbines to adapt to fuel variations driven by the need to reduce CO 2 emissions through the use of synthetic hydrogen rich fuels (Syngas) typically generated from the gasification of coal or solid waste. Syngas containing 80% hydrogen has been used in this study in a heavy duty gas turbine modified to accommodate the low calorific value fuel. Calculations were conducted on the baseline gas turbine originally designed for natural gas for the comparative study. Applying combustor representative hot streak profiles, analyses were performed for different hot streak distributions and locations. Analysis of results focused on the segregation of cold and hot fluid patterns and the effects of hot streaks on secondary flows and temperature re-distributions up to the second turbine stage. The hot flow pattern is affected by the fuel composition, resulting in more concentrated thermal wake shapes for syngas when compared to the reference natural gas fuel. In effect, the interaction with the secondary flow leads to more intense flow turning of the pressure side leg of the horseshoe vortex in the first rotor passage. The higher temperature levels in the case of syngas, in combination with the effect of the enhanced secondary flow, result in higher radial spread of the hot fluid that tends to migrate towards the blade hub and tip with the effects being obvious further downstream the first turbine stage. Permanent repository link

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Effect of Nonuniform Inlet Conditions on Endwall Secondary Flows

Cited by 28 publications

References 19 publications

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and End Wall Heat Transfer: An Experimental and Computational Investigation

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and End Wall Heat Transfer: An Experimental and Computational Investigation

Aerodynamic and aeroelastic experimental investigation on the propagation of inlet temperature distortions in a low pressure turbine stage

Full annulus numerical study of hot streaks propagation in a hydrogen-rich syngas-fired heavy duty axial turbine

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