Analysis on a Snow-Water Mixture Flow in a Horizontal Pipe by Three-Layer Model

Abstract

This paper is concerned with particle (polystyrene) velocity profiles in a horizontal pipe. In order to analyze a snow-water mixture flow, three-layer model was proposed. This model consi sted ofi) A Layer : The layer in which suspended particles concentrate.(The velocity gradient is not zero.)ii) B Layer : The plug layer (The velocity gradient is zero.)iii) C Layer : The layer which eddy motion of water particles is dominant.(The velocity gradient is not zero.).By using above model, the velocity profiles were derived as Eq. (30) and (31).Particle velocity profiles were measured using a high speed video camera and X-Y Coordinator. At lower velocities, the length of A Layer was rather larger than other Layers. On the other hand, the length of B Layer increased with increasing the mean velocity in the pipe. At higher velocities (>2m/s), A Layer changed into C Layer, and then the flow could be regarded as a Bingham plastic flow.Calculated values of the particle velocity profiles were compared with the experiments. The agreement was satisfactory regardless of the mean velocity in the pipe. So, this three-layer model could be considered to be reasonable.The pressure loss of a snow-water mixture flow was considered using this three-layer model, and Eq. (28) was obtained. The calculated values of the pressure loss were well agreed with the experiments. That is, the three -layer model proposed in this paper satisfied both velocity profiles and the pressure loss of a snow-water mixture flow in a horizontal pipe.