Heat (Mass) Transfer in a Diagonally Oriented Rotating Two-Pass Channel With Rib-Roughened Walls

Abstract

Naphthalene sublimation experiments have been conducted to examine the effects of channel orientation, rotational Coriolis force, ad a sharp turn, on the local heat (mass) transfer distributions in a two-pass square channel with rib-roughened walls, rotating about a perpendicular axis. The test channel was oriented so that the direction of rotation was perpendicular or at a 45 deg angle to the leading and trailing walls. In the two straight passes of the test channel, there were parallel 90 or 60 deg ribs on the leading and trailing walls. The test channel modeled serpentine cooling passages in modern gas turbine blades. The results showed that the heat (mass) transfer was very low on the leading wall of the first pass when the channel was oriented with the rotating direction normal to the leading and trailing walls. There were regions of very low heat (mass) transfer on both the leading and trailing walls in the turn, especially on the trailing wall in the turn when the channel with transverse ribs was oriented diagonally. For the given diagonal channel orientation, rotational Coriolis forces caused the leading and trailing wall heat (mass) transfer to be high near the outer edges of the walls in the channel with transverse ribs; rotation-induced secondary flows dominated near wall rib-induced secondary flows in the channel with angled ribs, since the heat (mass) transfer was generally higher near the outer edges of the walls than near the inner edges in the first and second straight passes. [S0022-1481(00)00201-2]

Effect of rib height on heat transfer in a two pass rectangular channel (AR=1:4) with a sharp entrance at high rotation numbers

“…The combination of these flows may result in further enhancement of the heat transfer, or they may have a negative impact on the heat transfer trend. The flow patterns previously described have been observed by previous studies (Han et al [20], Han and Zhang [21], Ekkad and Han [22], Park and Lau [23], Park et al [24], Liou et al [25], Liou and Chen [26], Liou et al [27]). …”

Heat Transfer Augmentation Technologies for Internal Cooling of Turbine Components of Gas Turbine Engines

“…Investigations which employ naphthalene sublimation to determine mass transfer generally obtain results which are consistent with heat transfer experiments [216,[238][239][240][241][242][243][244][245][246][247]. However, one drawback of such mass transfer methods is the absence of buoyancy within experiments.…”

Heat Transfer Technology for Internal Passages of Air‐Cooled Blades for Heavy‐Duty Gas Turbines

“…Therefore a large number of experimental investigations addressing these factors have been performed. The effect of wall heating conditions and model orientation were investigated for example in76–78. Only a few studies investigated the rotation effects in triangular79 and narrow rectangular ducts80 typical for leading and trailing edge channels.…”