Fundamental study on hydraulic transport of snow and ice particles. Drag coefficient of ice particles

In this paper, drag coefficients of sphere and non-sphere ice particles and its effects on pressure loss in ice-water two-phase flow were described. Drag coefficients of sphere ice particles fell close to the previous C_D-Res curve (drag coefficient-particle Reynolds number), while those of non-sphere ice particles were in the range of 1-6 in this experiment. Particle motion in water was analyzed by the equation of motion taking into account Basset term. By comparing the experimented particle trajectories with calculated ones, it was confirmed that the Basset term played an important role in motion of particles with densities near that of water such as snow, ice and polystyrene. Pressure loss for ice-water two-phase flow was measured and compared with the results calculated by Durand's and Newitt's equation. The use of adequate drag coefficient in Durand's equation gave a good agreement between the experimental results and calculated ones at low velocities. At high velocities, a discrepancy was observed because Durand's equation always gave positive values, but negative values of pressure loss coefficients were obtained in this experiment. Newitt's equation showed larger values than the experiments because this equation was applicable to the flow with a moving bed.