2D Model of Transfer Processes for Water Boiling Flow in Microchannel

The modeling of transfer processes is a step in the generalization and interpretation of experimental data on heat transfer. The developed two-dimensional model is based on a homogeneous mixture model for boiling water flow in a microchannel with a new evaporation submodel. The outcome of the simulation is the distribution of velocity, void fraction and temperature profiles in the microchannel. The predicted temperature profile is consistent with the experimental literature data.

Experimental Investigation of Large Particle Slurry Transport in Vertically Oscillating Pipe for Subsea Mining

For subsea mining, it is important to predict the pressure loss in oscillating pipes for the safe and reliable operation of ore lifting as well as the design of lifting system. In the present paper, the authors focused on the internal flow in vertical lifting pipe oscillating in the axial direction and carried out slurry transport experiment to investigate the effects of pipe oscillation on the pressure loss. The spherical alumina beads and glass beads were used as the solid particles in the experiment, and the oscillating periods and amplitudes of pipe model as well as the solid concentrations and the mean slurry velocities were varied. The time-averaged components of hydraulic gradient calculated by the prediction method for the steady flow proposed in the past by the authors agreed well with the experimental ones. As for the fluctuating components of hydraulic gradient, the calculation results using a homogeneous mixture model were compared with the experimental data. The comparison result indicated that the homogeneous mixture model would be applicable to the prediction of pressure loss in the vertical pipe oscillating in the axial direction.

Considering the Diffusive Effects of Cavitation in a Homogeneous Mixture Model

Homogeneous mixture models are widely used to predict the hydrodynamic cavitation. In this study, the constant-transfer coefficient model is implemented into a homogeneous cavitation model to predict the heat and mass diffusion. Modifications are made to the average bubble temperature and the Peclet number for thermal diffusivity in the constant-transfer coefficient model. The evolutions of a spherical bubble triggered by negative pressure pulse are simulated to evaluate the prediction of heat and mass diffusion by the homogeneous model. The evolutions of three bubbles inside a rectangular tube are simulated, which show good accuracy of the homogeneous model for multibubbles in stationary liquid.

An Efficient Shock-Capturing Scheme for Simulating Compressible Homogeneous Mixture Flow

In this paper, we focus on using high-resolution implicit upwind shock-capturing scheme to avoid the formation of non-linear instabilities and numerical oscillations across shock waves or discontinuities. The governing equation is the compressible Reynolds Averaged Navier-Stokes equation based on the homogeneous mixture model. A preconditioned method is applied for enhancing efficient and accurate computations over a wide range of Mach numbers. For evaluation, the results from the present study have been compared with experiments and other numerical results. A fairly good agreement with the experimental data and other numerical results have been obtained. Finally, the simulation of ventilated supercavitating flows over a torpedo with a hot propulsive jet was conducted to verify the efficiency of numerical scheme.