Heat Transfer in Rotating Serpentine Passages With Trips Skewed to the Flow

B. V. Johnson, J. H. Wagner, G. D. Steuber, F. C. Yeh
1992 Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration   unpublished
Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large scale, multi-pass, heat transfer model with both radially inward and outward flow. Trip strips. skewed at 45 degrees to the flow direction, were machined on the leading and trailing surfaces of the radial coolant passages. A n analysis of the governing flow equations showed that four parameters influence the
more » ... eat transfer in rotating passages: coolant-to-wall temperature ratio, rotation number. Reynolds number and radius-to-passage hydraulic diameter ratio. The first three of these four parameters were varied over ranges which are typical of advanced gas turbine engine operating conditions. Results were correlated and compared to previous results from similar stationary and rotating models with smooth walls and with trip strips normal to the flow direction. The heat transfer coefficients on surfaces, where the heat transfer decreased with rotation and huoyancy. decreased to as low as 40 percenl of the value wthout rotation. However, the maximum values of the heat transfer coefficients with high rotation were only slightly above the highest levels previously obtained with the smooth wall model. It was concluded that (1) both Coriolis and buoyancy effects must be considered in turbine blade cooling designs with trip strips. (2) the effects of rotation are markedly different depending upon the flow direction and (3) the heat transfer with skewed trip strips i s less sensitivity to buoyancy than the heat transfer in motleis with either smooth walls or normal trips. Therefore, skewed trip strips rather than normal trip strips are recommended and peometry-specific tests will be required for accurate design information. NOMENCLATURE
doi:10.1115/92-gt-191 fatcat:jrqyncgjxrfq5fdbefgrrvepoe