Determination of Convective Diffusion Heat/Mass Transfer Rates to Burner Rig Test Targets Comparable in Size to Cross-Stream Jet Diameter

Abstract

Two sets of supplementary experiments have been performed to be able to predict the convective diffusion heat/mass transfer rates to a cylindrical target whose height and diameter are comparable to, but less than, the diameter of the circular cross-stream jet, thereby simulating the same geometric configuration as a typical burner rig test specimen located in the cross stream of the combustor exit nozzle. The first set exploits the naphthalene sublimation technique to determine the heat/mass transfer coefficient under isothermal conditions for various flow rates (Reynolds numbers). The second set, conducted at various combustion temperatures and Reynolds numbers, utilizes the temperature variation along the surface of the abovementioned target under steady-state conditions to estimate the effect of cooling (dilution) due to the entrainment of stagnant room temperature air. The experimental information, combined with an analytical treatment, is used to predict high-temperature, high-velocity corrosive salt vapor deposition rates in burner rigs on collectors that are geometrically the same. The agreement with preliminary data obtained from Na2SO4 vapor deposition experiments is found to be excellent.