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A numerical and experimental study of flow and heat transfer from a flush inclined film cooling slot

University of British Columbia

Numerical and experimental results are presented for a simple, two dimensional flow from a flush, inclined slot in a flat plate. The geometry and mass flow conditions represent film cooling flows issuing from flush, inclined slots. The numerical velocity field predictions compare favourably with detailed flow measurements. Preliminary calculations of the heat transfer downstream of injection are also presented. Work done subsequent to this thesis indicates that the slot flow rate calibration may have been incorrect by 13 percent during the experiments. No correction for this possibility has been made here but a change, if made, would reduce the measured mass flow rates by 13 percent and would probably improve the agreement between measured and calculated velocity distributions. Experimental observations and measurements indicate that the velocity of the flow exiting the slot is non-uniform in both magnitude and direction. The variation of flow direction in the slot could not be measured in this study. Consequently, several assumed distributions are used to elucidate the effect of flow angle variation on film cooling performance. The flow field is shown to be essentially insensitive to the non-uniformities in magnitude and direction of the slot flow. However, the predictions of wall shear stress and wall heat transfer downstream of injection are significantly affected by the non-uniformities in the slot. Differences of 80 to 100 percent are predicted depending on the flow angle distribution. These effects are shown to be most significant within 40 slot widths of the slot. The results presented here may have important implications in prediction of the performance of various film cooling schemes. Furthermore, they point to a need for detailed flow measurements within and near modern film cooling orifices.

Text

2010-08-31

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http://hdl.handle.net/2429/28064

Mechanical Engineering

University of British Columbia

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