Numerical simulation of turbulent heated liquid and subcooled boiling flows with input from experiments

Numerical simulation of turbulent liquid flow through a heated annular channel has been carried out followed by numerical simulation of turbulent subcooled boiling flow through the same channel. For the former simulation, the Reynolds-averaged Navier Stokes (RANS) and thermal energy equations were solved. Two approaches were used for closure of these equations. In one approach, near-wall two-equation models of turbulence for the velocity and thermal fields were used. In addition, a near-wall turbulent heat flux model was incorporated. In the second approach, a high-Reynolds number two-equation model of turbulence for the velocity field, turbulent Prandtl number, and velocity and temperature wall laws were employed. The wall laws for the heated liquid flow were obtained from experimental measurements which were performed in parallel. A two-component laser Doppler velocimeter (LDV) in conjunction with a fast-response cold-wire were used for the turbulent field measurements Selected results from the simulations were compared with measurements. Good agreement was found especially in the case of the near-wall approach.;The two-fluid model conservation equations for mass, momentum, and thermal energy, and the corresponding interfacial balance relations were solved to simulate turbulent subcooled boiling flow. The turbulent viscosity of the liquid phase was considered to be comprised of shear-induced and bubble-induced components. The shear-induced component was obtained using a standard two-equation model of turbulence. The bubble-induced component was calculated from a well known model. The wall laws for the liquid phase velocity and temperature were developed from experimental measurements which were performed in parallel, as was the turbulent Prandtl number distribution for the liquid phase. The same LDV system and the cold-wire were employed for the measurements. Selected results from the simulations were compared with measurements. Good agreement was found for some flow field quantities while the agreement was only fair for others.;This study constitutes the first effort in which simulation of turbulent boiling flow has been performed in synergy with experiments which provide some of the important closure quantities for the model equations.