Nonsilting transport characteristics of coal slurry in a deep underground fluidization conveying pipeline under the action of a guide vane swirler

Abstract

The depth of coal mining is expected to increase continuously owing to the exhaustion of shallow coal resources. However, with the continuous increase in mining depth, transportation and lifting difficulties in deep mines have significantly increased, and traditional wire rope lifting methods can no longer meet the needs of deep transportation. Based on the principle of pipeline hydraulic lifting, a deep coal fluidization pipeline lifting system has been proposed. To address the problem of particle settlement in the horizontal connection section of large particles, a scheme involving the installation of guide vane-type swirlers in the conveying pipeline is proposed. First, the impact of the guide vane parameters on the liquid flow field and solid particles within the pipeline was studied, and a mathematical model of the characteristic parameters of the swirler was established. Suitable guide vane parameters for the swirler were determined by considering factors such as the alleviation of particle settling, energy utilization efficiency, and the structural strength of the swirler. On this basis, the movement patterns of particles of different sizes in pipelines with and without swirlers were investigated. The study found that under conditions of high velocity and large particle size, the swirler was more effective in improving the slurry flow state within the pipeline. Subsequently, a quantitative method for determining the slurry flow state in the spiral flow pipeline was established, using the particle proportion within the pipeline section as an evaluation index, while considering flow velocity and particle size. Finally, the bench test results show that adding a swirler can reduce the critical nonsilting velocity and resistance loss of the slurry conveying pipeline by 9.0% and 42.9%, respectively, and we elucidate the internal mechanisms behind these reductions.

Keywords

critical nonsilting velocity / flow state / guide vane parameters / pipeline transportation / resistance loss / swirler

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2025 The Author(s). Deep Underground Science and Engineering published by John Wiley & Sons Australia, Ltd on behalf of China University of Mining and Technology.