Detailed Measurements of Three-Dimensional Flows and Losses Inside an Axial Flow Turbine Rotor

Yamamoto, Atsushi; Tomlnaga, Junichi; Matsunuma, Takayuki; Outa, Eisuke

doi:10.1115/94-gt-348

Cited by 20 publications

(16 citation statements)

References 8 publications

(5 reference statements)

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“…Several previous studies have observed some interaction between the pressure surface separation and the secondary flow [2][3][4]. These studies were primarily concerned with the effects of incidence.…”

Section: Introductionmentioning

confidence: 99%

Pressure Surface Separations in Low-Pressure Turbines—Part 2: Interactions With the Secondary Flow

Brear

Hodson

González³

et al. 2002

Journal of Turbomachinery

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This paper describes a study of the interaction between the pressure surface separation and the secondary flow on low pressure turbine blades. It is found that this interaction can significantly affect the strength of the secondary flow and the loss that it creates. Experimental and numerical techniques are used to study the secondary flow in a family of four low pressure turbine blades in linear cascade. These blades are typical of current designs, share the same suction surface and pitch, but have differing pressure surfaces.A mechanism for the interaction between the pressure surface separation and the secondary flow is proposed and is used to explain the variations in the secondary flows of the four blades. This mechanism is based on simple dynamical secondary flow concepts and is similar to the aft-loading argument commonly used in modern turbine design.

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Section: Introductionmentioning

confidence: 99%

Pressure Surface Separations in Low-Pressure Turbines—Part 2: Interactions With the Secondary Flow

Brear

Hodson

González³

et al. 2002

Journal of Turbomachinery

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“…In the rotor, large fluctuation occurs in the stagnation area (indicated by ST) which corresponds to the inlet of some amount of the leakage flow, and also in the downstream half of the rotor passage where the fluctuation spreads widely in the Cate-Ade circumferential direction. The latter fluctuation occurs in the following manner (see also Yamamoto, et al, 1994): (1) Since the inlet flow collides with the blade suction side of the leading edge with a fairly large negative incidence, the cascade inlet flow separates from the pressure side of the leading edge. (2) Low energy fluids generated by this separation, which are initially distributed in the blade spanv.ise direction over the blade pressure surface near the leading edge, are driven toward the tip or the hub endv.alls by the tip-and hub-side passage vortices.…”

Section: Experimental Methods and Analysis Methodsmentioning

confidence: 99%

“…The present results were compared to some other test results separately obtained inside the rotor passage with five-hole Pitot tubes. Details of the measurements in the rotational frame of reference may be found in Yamamoto et al (1994). of the total pressure loss can be known from that of the random fluctuations of the static pressure.…”

Section: Experimental Methods and Analysis Methodsmentioning

confidence: 99%

Unsteady Endwall/Tip-Clearance Flows and Losses due to Turbine Rotor-Stator Interaction

Yamamoto¹,

Matsunuma

Ikeuchi

et al. 1994

Volume 1: Turbomachinery

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Unsteady static pressure on the tip endwall of a 1.5-stage lowspeed axial-flow turbine was measured in detail using a micro high-response pressure transducer to investigate effects of rotorstator interaction on the endwall and tip-clearance flows which play important roles in turbine loss generation process. In the present paper, distributions of the time-averaged and the timedependent pressures over the rust-stage rotor and the secondstage stator are presented. Also time-averaged and timedependent random fluctuations of the pressure were analyzed to understand unsteady behaviors of the flows and the associated losses over the endwall as well as inside the blade tip clearance. These unsteady characteristics were described for three rotor speeds with different incidences or loadings. Significantly large random fluctuations occur around the blade surfaces, particularly at the inlet and the outlet of the tip gap of the leakage flows, and in a flow separated region from the blade leading edge in a large negative incidence case A strong relation was found between the random fluctuation of the endwall static pressure and the total pressure loss inside the rotor, where large random fluctuation is attributed to high loss and vice versa. It can be seen clearly that the loss generation process is fairly unsteady due to the rotor-stator interaction.

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“…The possibility of reducing tip leakage flows through a reduced loading of the tip region has been discussed in De Cecco et al [10], Yamamoto et al [11]. Staubach et al [12] achieved the off-loading of the tip by applying 3D design strategies to the profiles.…”

Section: Introductionmentioning

confidence: 99%

Control of Rotor Tip Leakage Through Cooling Injection From the Casing in a High-Work Turbine: Experimental Investigation

Behr

Kalfas

Abhari

2007

Volume 6: Turbo Expo 2007, Parts a and B

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This paper presents an experimental investigation of a novel approach for controlling the rotor tip secondary flow by injecting cooling air from the stationary casing onto the rotor tip. It contains a detailed analysis of the unsteady flow interaction between the injected air and the flow in the rotor tip region and its impact on the rotor secondary flow structures.The experimental investigation has been conducted on a one-and-1/2-stage, unshrouded turbine, which has been especially designed and built for the current investigation. The turbine test case models a highly-loaded, high-pressure gas turbine stage. Measurements conducted with a twosensor fast response pressure probe (FRAP) have provided data describing the time-resolved behavior of flow angles and pressures, as well as turbulence intensity in the exit plane of the rotor. Cooling air has been injected in circumferential direction at a 30° angle from the casing tangent, opposing the rotor turning direction through a circumferential array of 10 equidistant holes per rotor pitch. Different cooling air injection configurations have been tested. Injection parameters such as massflow, axial position and size of the holes have been varied to see the effect on the rotor tip secondary flows.The results of the current investigation show that with the injection, the size and the turbulence intensity of the rotor tip leakage vortex and the rotor tip passage vortex reduce. Both vortices move towards the tip suction side corner of the rotor passage. With an appropriate combination of injection massflow rate and axial injection position the isentropic efficiency of the stage was improved by 0.55 percent points.

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Detailed Measurements of Three-Dimensional Flows and Losses Inside an Axial Flow Turbine Rotor

Cited by 20 publications

References 8 publications

Pressure Surface Separations in Low-Pressure Turbines—Part 2: Interactions With the Secondary Flow

Pressure Surface Separations in Low-Pressure Turbines—Part 2: Interactions With the Secondary Flow

Unsteady Endwall/Tip-Clearance Flows and Losses due to Turbine Rotor-Stator Interaction

Control of Rotor Tip Leakage Through Cooling Injection From the Casing in a High-Work Turbine: Experimental Investigation

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