Abstract
The frictional pressure loss of the snow-water mixture in circular straight pipes was investigated experimentally. The pressure losses both in a vertical and a horizontal pipe with an inner diameter of 40 mm, as well as the flow rate and the mixing ratio of snow in the discharge, were measured. The flow patterns were observed at the transparent parts of the pipe. The results were compared with those for the mixture of water and plastic beads, of which the size and the difference of density with water were nearly equal to those of snow used in this experiment.
Snow particles usually adhered to each other to make a large cluster whose dimension was nearly 50-80% of the pipe diameter, and the flow pattern did not change much with the flow rate or the mixing ratio of snow. The position of the pipe, that is whether it was horizontal or vertical, did not affect these flow patterns so evidently as it did in the case of the plastic beads mixture. At Reynolds numbers (Rm) below 5 × 104 the coefficient of pipe friction was larger than that for water and increased with the mixing ratio of snow. At Rm above 5 × 104 (or the velocity larger than 2 m/s) it was nearly equal to that for water independent of the mixing ratio of snow or the inclination of the pipe.
