Abstract
In order to improve the efficiency of the hydraulic conveying of snow by a pump-pipeline system, techniques to measure and control the in-situ concentration of snow/water mixture flowing in a pipe were developed, and the optimum condition was discussed on the basis of high concentration data obtained by applying these techniques.
The volume snow fraction in pipe, C, was determined by the in-situ concentration meter devised here in the range of C=030% within 3% error. Using the devised water-separator, an instrument to extract water from the mixture flowing in a pipe, a high concentration flow up to C=35% was attained. This upper limit of C was caused by the choking of the water separator with a densified snow cluster.
When C was greater than a critical value, Ccr, the pressure loss in a horizontal pipe increased rapidly with C, deviating from the value predicted by the method proposed so far. Although Ccr depends slightly on the flow velocity, roughly speaking, Ccr≥25% for the granulated snow and Ccr≥22% for the fresh snow.
It was concluded that the power loss was minimized when C=Ccr under the condition that the mass flow-rate of snow and the conveying distance were given.
