Theory Research Of Pipeline Solid-liquid Two-phase Slurry Transportation

With the development of pipeline technology and fierce competition of transport industry, pipeline technology has been used more and more widely in the world. The application of pipeline technology has brought much more convenient in coal mine, metal mine, ocean mining and other fields, whose advantage is far greater than in other modes of transportation. However, the solid-liquid two phase slurry pipeline transportation theory research still need to be further improved, especially the study of critical velocity and hydraulic gradient. Pipe critical velocity and hydraulic gradient are important parameters in slurry pipeline transportation, which are directly related to the safety, productiveness and efficiency of the pipeline.Based on the enterprise pipeline project as the background, with the pipe critical velocity and hydraulic gradient as the main research objects, this paper introduces the general situation of the pipeline system and the two-phase flow, and then detailedly introduces three kinds of research methods of the two-phase flow. According to the comparison with single phase flow, this paper deduces the basic equation of solid-liquid two-phase flow and BBO equation, analyzes the stress distribution of solid particles in the flow field, with the dynamic equations of solid particles movement, analyzes the solid particles form of exercise. This paper introduces the flow pattern and viscosity of slurry, analyzes the flow state of solid-liquid two-phase flow in the pipeline transportation, deduces the settling velocity formula of particles in the water and redefines the critical velocity of pipeline. Based on the theory of conservation of energy, combining with the relationship of slurry concentration and the critical flow velocity and the influence of material characters and turbulence intensity on critical velocity, this paper deduces the new critical velocity formula and validates the new critical velocity formula from the slurry concentration, slurry viscosity and material characters, analyzes the pipeline resistance loss mechanism and the factors affecting resistance loss. According to the relationship of the resistance loss and slurry flow velocity, this paper analyzes the change law of resistance loss under the different slurry flow states, introduces the common resistance reduction measures and analyzes their resistance reduction mechanisms and resistance reduction effect. Based on the pipeline hydraulic gradient calculation theory, this paper analyzes several typical hydraulic gradient formulas, proposes the new calculation method of hydraulic gradient and develops the corresponding calculation software. This paper measures the density of the material, grain size distribution, slurry settling velocity, slurry rheological parameter and hydraulic gradient by the experiment, then compares and analyzes the measured data of hydraulic gradient and the calculated values of two calculation methods of hydraulic gradient.Through this paper's research, the deducing process of new pipeline critical velocity formula is clear and reasonable. In addition, the calculated values of the new pipe critical velocity formula are close to experimental values and they have same change rule. According to the research of Wasp hydraulic gradient calculation method, the thinking of the new hydraulic gradient calculation method is clear and reasonable. In addition, the calculated values of the new hydraulic gradient calculation method are close to experimental values and the corresponding hydraulic gradient calculation software is developed. In this paper, the critical velocity and hydraulic gradient of pipeline research enriches and deepens the theory of solid-liquid two-phase slurry pipeline transportation, and they have a biggish guiding significance to pipeline engineering design.