Calculation of ammonia turbulent flow in circular heated tubes with catalytic dissociation on the walls

Calculation of heat and mass transfer at turbulent flow of ammonia catalytically dissociating on the wall of the heated tube using the Prandtle model with the damping Van-Dryist and k-epsilon turbulence model for determination of the turbulence viscosity coefficient is carried out. Possibility of using these models for calculation of normal and crisis flow modes is discussed. Data on the degree of diffusion separation of elements at turbulent flow of the dissociating ammonia are presented. The conducted calculations show that use of modification of k-epsilon-turbulence model permit to qualitatively correctly describe the phenomenon of turbulent flow laminarization in the tubes under the conditions of essential thermal loadings. At the same time use of the algebraic Prandtle model with the damping Van-Dryist multiplier permitting to essentially reduce the computation time expenditures is advisable for calculation of flow modes with normal heat transfer