Pressure and Flowrate Characteristics of Free Fall Backfill System
A free fall backfill(FFB)system with high-concentration slurry in a mine was taken as an example to study pipeline parameters and resistance characteristics of FFB system by conducting theoretical analysis,laboratory test and verification with field measurement.The results show that the FFB system has many working procedures,with flowrate for normal backfilling fluctuating within the range of 100-240 m3/h,and the pressure at 1.2-2.2 MPa.The flowrate at specific points of the pipeline presents a quasi-normal distribution,averaging 190 m3/h.There are two characteristic peaks for the pressure,being 1.86 MPa and 3.04 MPa,respectively.The parameters at a single point of pipeline cannot be used to analyze and judge the working conditions,such as pipe blockage and leakage.The pressure difference and flowrate difference between sections of the pipeline present obvious normal distribution,with mathematical statistics expectations of 4.62 m3/h and 0.64 MPa,respectively.The difference in instantaneous flowrate and pressure can be used to judge blockage and leakage of the pipeline.The flow resistance in the laminar-turbulent transition zone predicted by the Swamee-Aggarwal formula is 2.08 MPa/km,which is consistent with the measured value of 2.15 MPa/km.
deep mine backfillfree fall backfill(FFB)systempipeline pressureflow resistanceflowrate of slurrypipeline transportation
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