Numerical and experimental investigation of anomalous shear stress and heat transfer behavior in two-phase bubble flows

In this paper our investigations are focused on the void profile form effect and forced flow direction effect on the liquid velocity profile and on the wall shear stress behavior. Results of two-phase flow structure measurements in an upward and downward bubbly flow are presented. Numerical simulation deals with modeling of void fraction distribution influence on velocity profiles and wall shear stresses (anomalous increase as compared to single-phase (and homogeneous void distribution) flow, which are experimentally observed. Implicit numerical method is developed to solve 2-D Reynolds-type equations. Discretization is carried out on the base of monotonous balance neutral difference schemes. Computational grids are irregular, which yields enlarged precision for thin boundary layers. The implicit iterative procedure is developed for securing convergent solution. The explicit incomplete factorization method is employed for linearized momentum difference equations solving. The comparison of calculation and experimental results has demonstrated their fairly satisfactory agreement