| Effect of hole shape on the heat transfer in a rectangular duct with perforated blockage walls Somin Shin
The Journal of Mechanical Science and Technology, vol. 22, no. 10, pp.1945-1951, 2008
Abstract : Heat transfer coefficients were measured by the improved hue detection based liquid crystal technique in a turbine
blade internal cooling passage model with blockage walls. In the experiments, blockages with 9 holes of circular, wide,
narrow shapes were used and for the circular shape, the number of hole of 7, 9, and 11 were tested. For all cases, the
perforated area was kept same. Results showed that the staggered impingement jets increased heat transfer coefficient,
however, pressure drop also increased greatly. Generally, Nusselt number ratio and the thermal performance factor
decreased as Reynolds number increased. For all Reynolds numbers tested, the blockage wall with wide holes gave
more uniform heat transfer coefficient and higher thermal performance factor. As the number of hole increased from 7
to 11, the distribution of heat transfer coefficient became uniform and the thermal performance factor increased.
Keyword :
Turbine blade cooling; Impingement cooling; Staggered jets; Thermal performance factor
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