Showing papers by "Richard J Goldstein published in 1988"

Turbulent Transport on the Endwall in the Region Between Adjacent Turbine Blades

Abstract: The complex three-dimensional flow in the endwall region near the base of a turbine blade has an important impact on the local heat transfer. The initial horseshoe vortex, the passage vortex, and resulting corner vortices cause large variations in heat transfer over the entire endwall region. Due to these large surface gradients in heat transfer, conventional measurement techniques generally do not provide in accurate determination of the local heat transfer coefficients. In the present study the heat/mass transfer analogy is used to examine the local transport coefficients for two different endwall boundary layer thicknesses and two free-stream Reynolds numbers. A linear turbine blade cascade is used in conjunction with a removable endwall plate. Napthalene (C{sub 10}H{sub 8}) is cast into a mold on the plate and the rate of naphthalene sublimation is determined at 6,000+ locations on the simulated endwall by employing a computer-aided data acquisition system. This technique allows one to obtain detailed contour plots of the local convection coefficient over the entire endwall. By examining the mass transfer contours, it is possible to infer information on three-dimensional flow in the passage between the blades. Extremely high transport coefficients on the endwall indicate locations of potential overheating and failuremore » in actual turbine.« less

Heat transfer from a flat surface to an oblique impinging jet

Abstract: Experiments are conducted to determine the heat transfer to a jet impinging at different oblique angles to a plane surface The main portion of the test plate contains a composite sheet of temperature-sensitive liquid crystal, which is sandwiched between a thin metallic-foil heater and a specially designed liquid bath The results indicate a displacement of the peak heat transfer from the geometric center of the jet origin, the displacement being a function primarily of impingement angle Contours of constant heat transfer coefficient are obtained and correlated with an empirical equation that permits determination of average Nusselt numbers over areas of interest

An experimental study on natural convection heat transfer in an inclined square enclosure containing internal energy sources

Abstract: An experiment was carried out to study two-dimensional laminar natural convection within an inclined square enclosure containing fluid with internal energy sources bounded by four rigid planes of constant equal temperature. Inclination angles, from the horizontal, of 0, 15, 30, and 45 deg for Rayleigh numbers from 1.0 {times} 10{sup 4} to 1.5 {times} 10{sup 5} were studied. At inclined angles of 0 and 15 deg, there are two extreme values of temperature and temperature gradient within the fluid, while there is only one at 30 and 45 deg. Local and average Nusselt numbers are obtained on all four walls. As the inclination angles increases, the average Nusselt number increases on the right (upper) and bottom walls, decreases on the left (lower) wall and stays almost constant on the top wall.

The two-dimensional behavior of film cooling jets on concave surfaces

Abstract: Comportement bidimensionnel d'un jet sur une surface concave dans le cas du refroidissement par film d'une aube de turbine