The heat/mass transfer analogy for a simulated turbine endwall

Heat transfer measurements in gas turbine cascades are often difficult because of thin boundary layers, complex secondary flows, and large variation in local heat transfer rates. Thus mass transfer techniques have often been used as an alternative method, the heat transfer coefficients being then calculated from the heat/mass transfer analogy. To ensure confidence in the quantitative conversion to the heat transfer coefficients from the mass transfer results, evaluation of the analogy factors is crucial. The present paper examines the validity of the heat/mass transfer analogy, evaluating the analogy factors on a simulated turbine endwall, with separate heat and mass transfer experiments with equivalent flow and geometric conditions. The Nusselt numbers, determined from the heat transfer experiments with a constant wall temperature boundary condition are compared to Sherwood numbers from the mass transfer experiments employing a constant wall concentration boundary condition to evaluate the heat/mass transfer analogy.