| This paper is based on the cut and fills mining of the gangue paste-like slurry, which belongs to the coal under the aquifer of the Gonggeyingzi, coal mine. This paper studied the rheological properties and the pipe flow characteristics of the gangue paste-like slurry,and then find out the optimal proportion of the gangue paste-like slurry through the experiment.Then it could determine the parameters of the filling system and guide the engineering practice by using numerical simulation method.Aiming at the important problem of slurry flow properties in the filling issues, I have read a great deal of literature and concluded a lot of research at home and abroad. Based on the rheology theory, the theoretical analysis about the rheological characteristics of coal gangue paste-like slurry was carried out, and aiming at the shortcomings of the present rheological measurement instruments, a new CRT rheometer was developed. The new CRT rheometer was used to carry on an experiment and research of the gangue pastelike slurry’s rheological behavior, and the rheological characteristics was summarized which was used to combine with the engineering practice to determined the optimum mixture ratio of the gangue paste-like. By the CFD、FLUENT and ICEM,I conducted the computer modeling to the tube flow characteristics of the gangue paste-like slurry, through the numerical simulation method, the dynamic features of gangue paste-like slurry in the pipeline delivery are studied to find out its numerical simulation method of the frictional resistance and nondeposit velocity. By using the Reynolds stress model, the secondary flow phenomenon and the gangue gathered phenomenon in the bend has carried on the preliminary study. For unsteady flow, especially the vertical section of slack pipe flow the computer modeling was conducted, combining the results of numerical simulation, the velocity field and pressure field of the gangue paste-like slurry’ slack tube flow was analyzed, the average speed and maximum speed was analyzed too, and then combined with the relevant theory of flow pipe damage,the pipeline damage rate has been carried on the quantitative analysis. Finally, combined with the real situation of the Gonggeyingzi coal mine’s filling site, this paper introduced the engineering application and determined the pipe diameter, bending radius and so on, the economic benefit is also analyzed, then the paper indicated superiority of stowing mining using gateway in Gonggeyingzi coal mine. The main research content of this paper is as follows:(1) Aiming at the shortcomings of the present rheological measurement an instrument, a new CRT rheometer was developed. Using the new CRT rheometer the gangue paste-like slurry’s rheological properties were studied.(1)the applicability of the existing rheometer for gangue paste-like slurry containing large particles is bad, so in order to solve this problem, i used the new type of mixing blades to improve the rheometer. In this paper, the design principle of the new type rheometer, structure, work mode were introduce, and had the calibration of the instrument.(2)Through the experimental test results and the rheological theory, it was summed up that the gangue paste-like is a kind of bingham fluid, which has the initial yield stress of Newton’s body, and then based on the above results the gangue paste-like rheological model was established.(3)Aiming at the concentration, the dosage of fine particles, the dosage of cementing material which have an influence on the rheological properties of the coal gangue pastelike slurry, the quantitative analysis was carried on. After the analysis of the influence on flow resistance, the suitable ratio of optimization was determined that: mass’ s concentration 78%, content of coal gangue is 53%, content of fly ash is 20%, content of gelling agent is 5%.(2) Using CFD, ICEM CFD, FLUENT and CFD – POST, the pipe flow dynamic characteristics of gangue paste-like slurry has been analyzed by numerical simulation. Then I respectively simulated the flow behavior of the slurry in different velocity under the stable flow state in the straight tube and bending tube, the analysis of gangue pastelike slurry’s non-silting velocity and frictional resistance has been done, and also the preliminary probe into the complex secondary flow in bend.(1)Using ICEM CFD as the pretreatment software and adopting the efficient gridmaking method, also non Newtonian turbulent model, the computer modeling of the coal gangue paste-like slurry’s pipeline transport has been conducted, which provide a model basis for the numerical simulation of different pipe shape and different velocity of the slurry.(2) The FLUENT software was used as a solver, introducing the solid-liquid multiphase flow model, to carry out the numerical simulation for the coal gangue pastelike slurry’s pipeline dynamic characteristics. And then use the Reynolds stress model which has much difference in common K-w model to carry out the numerical simulation of the slurry.(3)The simulation found that in straight pipe, due to the effect of friction resistance, pressure drop and flow plug exist. At low speed, the gangue paste-like slurry is in laminar state, which verified the eulerian multiphase flow model’s simulating ability for complex solid-liquid multiphase flow, explored the numerical simulation method of the mixed multiphase flow of the non Newtonian field and solid particle. The simulation also found that the slurry under the laminar state, with the increase of flow velocity, the flow plug became smaller, the speed of flow plug increases gradually, the head loss increases gradually; and then with the increase of the pipe diameter, the frictional resistance of the gangue paste-like slurry decreases. It explored the method of analyzing gangue paste-like slurry’s settlement of solid state, and the method of analyzing nondeposit velocity by numerical simulating.(4)The pressure field of bend pipes with different bending radius were analyzed, and the analyzing results show that it exists the head loss in the bent pipe, the value of the head loss is related to the bend radius, the greater the bending radius of bend pipe is, the smaller is the slurry’s pressure drop in bend pipe, so we can concluded that combined with the actual situation we should choose the larger bending radius in engineering.(3) Using the phase model of FLUENT software, the slack the numerical simulation of the pipe flow in vertical section has been carried out. It analyzed the velocity field of the pipe flow and pressure field, combined with the frayed theory, the wear slack line flow sessions to the pipeline have been quantitatively analyzed.(1)This paper expounds the occurrence mechanism of two typical unsteady flow, especially points out that the slack pipe flow is due to the accelerated motion of the slurry which made the original slurry column be drawn into small segmented body, then small section of the body divided into small groups or particles moving in the form of jet downward.(2)Use former processing software to carry out the computer modeling of the slack pipe flow, adopt meshing method which improved the operating efficiency and accuracy.(3)Respectively using different turbulent model, validate the different model’s simulation effect to different slack pipe flow through the comprehensive evaluation of the jet, phase transition and slurry indexes of briquette, then ultimately determine the SST discontent-KW as the best pipe flow simulation of turbulence model.(4)By numerical simulating the different velocity field of the gangue paste-like slurry, it can be found that the maximum speed can be 62.5m/s, accompanied by severe cavitation phenomenon and eddy current at the same time, in the eddy current the slurry keep changing direction. The Slurry’s average air content is 60% ~ 70%, which is the important cause of blockage. Combining with frayed Hutchings theory, it demonstrated that the wear speed of slurry to pipe is directly proportional to the square of slurry speed.(5)After numerical simulating to the pressure field to the slack pipe flow, it can be found that the pressure is always near the water saturation vapour pressure fluctuation, so we can conclude that cavitation phenomenon is a kind of dynamic balance.(4) Combined with the engineering application, i used the method of numerical simulation approaches to select the stowing mining pipe parameters of GongEgeyingzi coal mine, including the selection of pipe radius, the calculation of nondeposit velocity and selection of bending radius, and also I observed the effect of filling and analyzed the technical and economic benefits.(1) This section briefly introduces the general engineering situation of the Gonggeyingzi coal mine, in view of the actual situation, and combined with the obtained above rheological properties of the gangue paste-like slurry, I use the filling capacity of 90 m3/h to design the parameters for simulation, by using numerical simulation method, to analyze the under the different nondeposit velocity of different pipe diameter, then finally I choose the 150 mm pipe.(2)Combined with the actual situation, the bending radius of bend pipe are analyzed by numerical simulation, through the analysis of the head loss of different bend pipe bending radius, I determine the pipe of bending radius R = 800 mm pipe for the pipeline layout.(3)This section also analyze economic benefit of the mining with coal refuse back stowing of gangue paste-like slurry, the results show that the mining with coal refuse back stowing can liberate 3 million tons coal, gain profit is 200 million Yuan, save drain expense more than 600 ten thousand Yuan/year, reduce the production cost nearly 20 Yuan/ton. At the same time the research and practice about filling pattern of gangue pastelike has opened up an ideal way to "three go" mining and green mining which contain much more social benefit and environmental benefit. |
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