Mixed convection over a vertical Zircaloy plate in steam with simultaneous oxidation

An analytical study is made of the quasi-steady, laminar, binary boundary layer flow of steam and hydrogen over a vertical Zircaloy plate under conditions pertinent to the Three Mile Island nuclear reactor accident. The experimentally observed oxidation rate law is modified to account for the possible presence of hydrogen in steam outside the boundary layer and for variable plate temperatures. The oxidation of Zircaloy gives rise to a small suction velocity of the steam-hydrogen mixture at the cladding surface. Details of the longitudinal and transverse components of the velocity profiles, temperature, and hydrogen concentration profiles across the binary boundary layer are presented as well as longitudinal distributions of wall suction velocity, wall shear, and wall temperature. A parametric study of the effect of surface radiative heat loss was made, using recently reported data on the radiation heat transfer coefficient. Correlations are proposed for the local wall temperature rise and for the local Nusselt and Sherwood numbers. (author)