Characteristics Of Rheological Parameters And Pipe Resistance Under The Time-temperature Effect

Paste filling technology is an important support for the development strategy of the national "green and deep mine".Pipeline transportation is a necessary condition for the high quality paste to be put into the stope and then successfully implement the expected performances.It is an effective method to analyze the characteristics of the pipeline resistance of the structure flow paste by rheology.However,the relationship between the rheological characteristics of the paste and the properties of the material and the variation rule of the rheological characteristics under the time-temperature effect are still not clear.At the same time,the characteristics of the paste pipeline resistance under the time and temperature also should be studied.Based on the basic properties of paste materials,the experimental and theoretical research on the influence factors of reheological parameters were carried out and then the prediction model of the rheological parameters of paste and the prediction model of paste pipeline transportation resistance with time and temperature effect were established and finally,the theoretical results were successfully applied to the mine filling practice.The main research contents are as follows:(1)The variation law of rheological parameters with slurry concentration,paste stability coefficient and specific gravity was proved.The paste stability coefficient was established to characterize the grading structure.The evolution mechanism of rheology under time-temperature effect is revealed from three scales,macro,meso and micro,and obtained the conclusion that the rheological parameters are dominated by the graded structure and the flocculation structure of slurry.Thixotropic process is the reflection of flocculation structure ordering,and the increase of temperature causes the floc structure into liquid structure.The flocculation structure is orderly under fluid drag force,and the yield stress and the plastic viscosity decrease.(2)The calculation models of the time-temperature response of yield stress and plastic viscosity were established.The quantitative analysis method of the thixotropy of the paste was developed,and considering shear rate and time factors.Coupling analysis of thixotropy and temperature was performed for the first time,and the variation law of yield stress and plasticity viscosity with shear time and temperature is obtained.According to the time-temperature equivalence principle,the prediction model of yield stress and plasticity viscosity under time-temperature effect were established.(3)Considering the effects of material properties,transport conditions and external field on the resistance,the calculation model of time-temperature response paste resistance was established.The distribution characteristics of paste resistance under six kinds of pipe arrangement were studied.The calculation method of filling times line under time-temperature effect was established and the key pipe sections of easy plugging and explosion accidents were quantified.(4)A numerical model of paste pipeline transportation under time-temperature effect was established,and the three dimensional structure of the paste was successfully reproduced.By means of discrete Navier-Stokes(N-S)equation with time and temperature factors,the velocity and pressure distribution of paste pipeline with time and temperature were calculated.The validity of mathematical model was verified.