Y. Barnea

University of British Columbia

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K. Zhang

University of British Columbia

I. S. Gartshore

University of British Columbia

Isaac Shai

Ben-Gurion University of the Negev

E. Elias

Technion – Israel Institute of Technology

D. Faraji

Arak University

Marthe Salcudean

University of British Columbia

M. Haim

Ben-Gurion University of the Negev

M. Salcudean

University of British Columbia

F. Aghadsi

University of British Columbia

M.E. Salcudean

University of British Columbia

Cooperative Institutions

University of British Columbia

Ben-Gurion University of the Negev

Technion – Israel Institute of Technology

National University of Singapore

FZI Research Center for Information Technology

Heidelberg University

Jerusalem College of Technology

Science Applications International Corporation (United States)

Oak Ridge National Laboratory

University of California, Berkeley

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Leading Edge Film Cooling of a Turbine Blade Model Through Single and Double Row Injection: Effects of Coolant Density

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration (1994)

M. Salcudean I. S. Gartshore K. Zhang Y. Barnea

Experiments have been conducted on a large model of a turbine blade. Attention has been focussed on the leading edge region, which has a semi-circular shape and four rows of film cooling holes positioned symmetrically about the stagnation line. The cooling holes were oriented in a spanwise direction with an inclination of 30° to the surface, and had streamwise locations of ±15° and ±44° from the stagnation line. Film cooling effectiveness was measured using a heat/mass analogy. Single row cooling from the holes at 15° and 44° showed similar patterns: spanwise averaged effectiveness which rises from zero at zero coolant mass flow to a maximum value η* at some value of mass flow ratio M*, then drops to low values of η at higher M. The trends can be quantitatively explained from simple momentum considerations for either air or CO2 as the coolant gas. Close to the holes, air provides higher η values for small M. At higher M, particularly farther downstream, the CO2 may be superior. The use of an appropriately defined momentum ratio G collapses the data from both holes using either CO2 or air as coolant onto a single curve. For η*, the value of G for all data is about 0.1. Double row cooling with air as coolant shows that the relative stagger of the two rows is an important parameter. Holes in line with each other in successive rows can provide improvements in spanwise averaged film cooling effectiveness of as much as 100% over the common staggered arrangement. This improvement is due to the interaction between coolant from rows one and two, which tends to provide complete coverage of the downstream surface when the rows are placed correctly with respect to each other.

Leading edge

Momentum (technical analysis)

Mass flow

Mass flow rate

10.1115/94-gt-002

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Citations (15)

Peak Temperature in a Semiconductor with a Clip-Type Dissipator.

M. Haim Y. Barnea

Source

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Flow and heat transfer regimes during quenching of hot surfaces

International Journal of Heat and Mass Transfer (1994)

Y. Barnea E. Elias Isaac Shai

Subcooling

10.1016/0017-9310(94)90146-5

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Citations (56)

VISUALIZATION STUDY OF VAPOUR BUBBLES IN CONVECTIVE SUBCOOLED BOILING OF WATER AT ATMOSPHERIC PRESSURE

Proceeding of International Heat Transfer Conference 9 (1994)

D. Faraji Y. Barnea M.E. Salcudean

Subcooling

10.1615/ihtc10.1230

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Citations (5)

Some Effects of Coolant Density on Film Cooling Effectiveness

I. S. Gartshore Marthe Salcudean Y. Barnea K. Zhang F. Aghadsi

Experiments have been conducted on a large wind tunnel model of the leading edge region of a turbine blade. The model had a semi-circular leading edge in which four rows of holes were symmetrically placed about the stagnation line, two at ±15° and two at ±44°. Air and alternatively CO2 were injected from the coolant holes after contamination with a known small percentage of propane. Using a flame ionization detector and the mass transfer analogy, the film cooling effectiveness was measured at various overall mass flow ratios and at various streamwise locations for each coolant type. The division of coolant flow rate from the two rows of holes was found to be more unequal for CO2 than for air, an effect which is predicted from a simple analysis of the coolant/free stream interaction and the hole discharge coefficient. This has practical implications for actual turbine operation since earlier cut-off of the coolant from the front row of holes, due to density differences, could have disastrous effects on the blade. This effect also further complicates any attempt to identify overall trends of coolant density on performance. It is not possible to conclude that air or CO2 coolant has a higher film cooling effectiveness, although, in general, air appears better close to the first row of holes, and CO2 better at some distance downstream of both rows. Based on the measurements, the effects of mass flow ratio, momentum flux ratio, relative hole placement in each row, and spanwise versus streamwise injection are discussed in the paper.

Mass flux

Mass flow rate

Mass flow

Leading edge

10.1115/93-gt-076

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Citations (10)

Simple analysis of mixed convection with uniform heat flux

International Journal of Heat and Mass Transfer (1986)

Isaac Shai Y. Barnea

Forced convection

Convection cell

Rayleigh–Bénard convection

Film temperature

10.1016/0017-9310(86)90145-6

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Citations (12)