An Experimental Investigation of the Flow Field and Heat Transfer from a Single Impinging Jet with Varying Confinement Conditions

The primary objective of this paper is to present the results of research into the effects of periodic excitation upon the local heat transfer characteristics of a turbine blade cooled by an impinging jet of air. A curved plate (used to simulate the inner leading edge of a turbine blade) was subjected to a two-dimensional jet flow field (Re = 10,000) with a superimposed periodic acoustic disturbance. When compared to the naturally disturbed flow, the excited flow field was found to reduce the local Nusselt number and cool the blade less efficiently (by as much as ten percent in the extreme cases). The results of the study appear to indicate that harmonic disturbances present a serious controlling factor in the quest for optimization of turbine blade cooling techniques. By isolating dominant frequencies in gas turbine engines and working to suppress them, the authors believe it possible to make significant contributions towards the desired increase in turbine inlet temperature.

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Experimental Investigation of the Aerothermal Performance of a High Blockage Rib-Roughened Cooling Channel

Journal of Turbomachinery ◽

10.1115/1.1928933 ◽

2005 ◽

Vol 127 (3) ◽

pp. 580-588 ◽

Cited By ~ 48

Author(s):

Luca Casarsa ◽

Tony Arts

Keyword(s):

Heat Transfer ◽

Experimental Investigation ◽

Flow Field ◽

Three Dimensional ◽

Heat Transfer Process ◽

Cooling Channel ◽

Complex Flow ◽

Turbine Blade Cooling ◽

Flow Features ◽

Rib Roughened

The present study deals with a detailed experimental investigation of the turbulent flow inside a rib-roughened turbine blade cooling channel. The measurements are carried out in a stationary straight channel with high blockage ribs installed on one wall. The main objective is to enhance the understanding and deepen the analysis of this complex flow field with the help of highly resolved particle image velocimetry measurements. A quasi-three-dimensional view of the flow field is achieved, allowing the identification of the main time-averaged coherent structures. The combined analysis of the present aerodynamic results with available heat transfer data emphasizes the role of the mean and fluctuating flow features in the heat transfer process. In particular, the stream wise/normal to the wall component of the Reynolds stress tensor is shown to be strictly related to the heat transfer rate on the channel surfaces. A correlation to estimate the heat transfer field from the aerodynamic data is presented for the high blockage rib roughened channel flow.

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Experimental Investigation of Characteristics of Impinging Jet Heat Transfer and Application to JSNS Moderator Design

Transactions of the Atomic Energy Society of Japan ◽

10.3327/taesj2002.5.179 ◽

2006 ◽

Vol 5 (3) ◽

pp. 179-189

Author(s):

Tomokazu ASO ◽

Masanori MONDE ◽

Hiroshi SATO ◽

Ryutaro HINO ◽

Hideki TATSUMOTO ◽

...

Keyword(s):

Heat Transfer ◽

Experimental Investigation ◽

Impinging Jet

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The Effects of Dimpled Surface Geometry on Heat Transfer in an Impinging Jet Flow

Heat Transfer, Volume 2 ◽

10.1115/imece2002-33718 ◽

2002 ◽

Author(s):

Ann M. Anderson ◽

David M. Chapin

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Heat Transfer Performance ◽

Impinging Jet ◽

Jet Flow ◽

Surface Flow ◽

Diameter Ratio ◽

Transfer Performance ◽

Surface Geometry ◽

Actual Surface

The objective of this study was to characterize the heat transfer performance of a dimpled surface in an impinging jet flow field. Using a statistical design of experiments approach we designed 8 (23) test plates to study the effects of dimple spacing, dimple depth and dimple diameter and compared them to smooth plate heat transfer. The plates were placed opposite a square jet and tests were run for Reynolds numbers based on jet hydraulic diameter of 10,000 to 30,000 at a range of jet to plate spacings. Plate averaged heat transfer coefficients, based on actual surface area (including dimple area) were measured under steady state conditions. The results show that the dimple spacing to diameter ratio has the most significant effect on heat transfer performance at high velocities, while the dimple depth to diameter ratio is more significant at lower velocities. The effect of dimple diameter was found to be significant only under poor heat transfer conditions. Particle Image Velocimetry images of the dimple surface flow field showed enhanced entrainment at high velocities which may explain why the dimple spacing to diameter effect is more significant at high velocities.

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