Experimental and Numerical Study on the Convective Heat Transfer and Pressure Loss in Rectangular Ducts With Inclined Pin-Fin on a Wavy Endwall

Abstract

Local endwall heat transfer characteristics and overall pressure loss of normal and inclined pin fins arrayed in rectangular ducts with flat and wavy endwalls have been investigated to improve the cooling efficiency of jet engine combustor liners. The detailed time-mean local Nusselt number profiles were measured using a naphthalene sublimation method based on the heat/mass transfer analogy. Four kinds of angled pin fins (−45, 0, and +45 degrees with a flat endwall, and −45 degrees with a wavy endwall) were tested and compared with each other. As a result, the average heat transfer coefficient on the flat endwall of normal pin fins was higher than that of the angled pin fins. The average heat transfer coefficient of −45-degree inclined pin fins with a wavy endwall is the same or a little higher than the heat transfer coefficient of those with a flat endwall; however, the pressure loss of the −45-degree inclined pin fins with a wavy endwall is less than the pressure loss of those with a flat endwall. Corresponding numerical simulations using Large Eddy Simulation (LES) with the Mixed Time Scale (MTS) model have been also conducted at Red = 1000 for fully developed regions, and the results have shown good quantitative agreement with mass transfer experiments. It can be concluded that wavy endwalls can realize better heat transfer with less pressure loss as long as the aim consists in enhancing endwall heat transfer in inclined pin-fin channels.

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

“…The combined use of inclined pin fins and wavy endwalls is described by Takeishi et al [174] and Motoda et al [175]. Typically, pin fins with angles of plus and minus 45 degrees, relative to the flat endwall plane, are employed.…”