不同浓度粉煤灰浆体管内流动规律试验研究

Experimental study on flow characteristics of fly ash slurry with different concentrations

粉煤灰浆体在矿山及地下工程中的使用越来越广泛,而其管道运输时的过渡流速、屈服应力衰减规律及紊流水力坡度方面的研究还略显不足,开展这方面的研究有重要的应用价值。为此本文进行了体积浓度为0.422,0.441,0.462和0.492的粉煤灰浆体在直径为0.0627m和0.0777m的水平管道中流动输送试验研究,通过试验数据分析,给出了浆体从层流到紊流的过渡流速值,结合前人研究成果,给出了浆体过渡流速计算公式。同时通过分析浆体切应力和切变率曲线,发现粉煤灰浆体流型为宾汉体。通过试验数据拟合法,给出了宾汉体屈服应力衰减系数与相对流速偏移量关系的表达式,由此给出了宾汉流体紊流水力坡度计算模型。对比结果表明,模型计算值与实测值最大偏差为9.42%。

Fly ash slurry is used more and more widely in mines and underground engineering, but the research on its transition velocity, yield stress attenuation law and turbulent hydraulic gradient in hydraulic transportation is still insufficient, so it is of important application value to carry out research on this area. In this paper, the flow transport experiments of volumetric fluids with a concentration of 0. 422, 0. 441, 0. 462 and 0. 492 in the horizontal pipelines with diameters of 0. 0627m and 0. 0777m were carried out. The experimental data were analyzed to give the slurry from laminar to turbulent flow. The transitional flow velocity value, combined with previous research results, gives the formula for calculating the slurry transition velocity.At the same time, by analyzing the slurry shear stress and shear rate curves, it turns out that the fly ash slurry flow pattern is Bingham flow. Through fitting the experimental data, the expression of the relationship between the yield stress attenuation coefficient and the relative flow velocity offset of Bingham body is given. The comparison results show that the maximum deviation between the calculated value and the measured value is 9. 42%.