Study On Affections Of Pipeline Diameter To The Transportation Characteristics Of Backfilling Slurry Of Unclassified Tailings Inner Pipe

The improvement of production capacity of filled stopes asks for enlargement of pipe diameter and slurry concentration, which results in the change of conveying characteristics of filling slurry inner pipe.. It has positive significance to improve the pipe transportation stability of backfilling slurry that the effect laws of pipe diameter to pipe transportation characteristics of backfilling slurry are studied.The affections of pipe diameter to velocity and concentration distribution along cross section of pipe are studied when backfilling slurry of unclassified tailings is conveyed with fluent-3d fluid mechanics software. The study results show that the cross section of pipe could be divided into 3 parts when backfilling slurry is conveyed with full pipe, i.e.increasing area of concentration, homogeneous area and decreasing area, the percentage of homogeneous area raise along with the enlargement of pipe diameter, however, it results in the further increase of concentration in increasing area and further decrease of concentration in decreasing area. On the other hand, the study also points out that the velocity gradients decline along cross section of pipe if initial velocities are same with the enlargement of diameter when backfilling slurry is conveyed with full pipe.Combining the methods of theoretical analysis, physical experiment with numerical analysis, rheological characteristics of backfilling slurry of different concentration are analyzed, the calculation model of critical conveying velocity that minimizes transport resistance is deduced, then the affections of pipe diameter to critical conveying velocity are studied. At the same time, the affections of pipe diameter to critical conveying concentration are studied which is combined with filling times line, rheological parameters and so on. The results shows that critical conveying velocity increases along with the enlargement of pipe diameter with power function, as well as0.379 c iV =AD( A í[0.26,0.50]), and critical conveying concentration increase along with the enlargement of pipe diameter with logarithmic function and correlativity is given out, i.e.()w iC =m Ln D +t.Using fluid mechanics software named fluent-3d, the affections of pipe diameter to conveying resistance loss are studied with different stowing gradients and backfilling slurry concentrations. The study pointed out that resistance loss takes on the decline relationship along with the enlargement of pipe diameter to resistance loss with the formula0.01 D pi je-=; that the affection relationship of pipe diameter to conveying resistance can’t change with different stowing gradient; that the change degree of conveying resistance loss along with pipe diameter is larger if backfilling slurry concentration is higher; and that along with the enlargement of pipe diameter, the affection of it comes to be gradual, the enlargement of pipe diameter can reduce the affection of concentration to resistance loss effectively, which explains that conveying high concentration slurry with pipes of large diameter has feasibility.