Bubbly flows through a converging–diverging nozzle

Characteristics of bubbly flow through a vertical, two‐dimensional, converging–diverging nozzle are investigated theoretically and experimentally. First, a new model equation of motion governing a dispersed bubble phase is proposed. This is compared in detail with those proposed previously by several researchers. Next, hyperbolicity of the resultant systems of governing equations for the bubbly flow is investigated in detail. Numerical simulations of bubbly flows through a converging–diverging nozzle are carried out by using the proposed system of model equations. In order to check the validity of the numerical results and then the proposed system, they are compared with the experiments which were performed previously in the authors’ laboratory in a water–nitrogen blow‐down facility. It will be shown that the numerical results obtained by using the proposed system of model equations agree well with the experiments.