Study On The Moving-effect And Its Aerodynamic Characteristics Generated By Hoisting Container In Vertical Shaft

The motion state of airflow in vertical draft was affected by many objective factors together. For ventilation shaft, the continuous rising-falling movement of mine hoisting container was the primary factor which results in the unsteady flow. Hoisting container took parts space of the vertical draft, and its lifting motion lead to the continuous change of cross-section of vertical draft. The piston-wind produced by its movement could lead to the frequent change of pressure of ventilation system, and then resulted in the panting of airflow. The lifting motion of mine hoisting container could be considered as the air flows around the cylinder in vertical pipe, it combined the airflow around the cylinder and pipe turbulence organically, would be a new research topic in the hydromechanics field, and had important practice significance for the development and deepen of classics hydromechanics theory. Using the unsteady flow theory of viscous fluid mechanics to research the moving-effect of hoisting container, was originality innovation to the traditional mine ventilation theory, would break through the current steady flow theory of mine ventilation. In order to ensure the veracity and scientificalness of the findings the, this study used the method which combined the theoretical derivation, actual measurement in scene and numerical simulation of CFD based on the theories such as mine ventilation theory, hydromechanics, aerodynamics and computation hydromechanics, and took full advantage of data of actual measurement to perfect the theoretical analysis and revise the model of CFD. For getting the degree of impact of the hoisting container to the mine ventilation system, supported by the Natural Science Foundation of China (50474062), this article set up the aerodynamics model of hoisting container, analysed the piston-pressure and piston-wind. The MVNS (Mine Ventilation Network Software) was used to calculate the wind assignment impacted by the piston-effect of hoisting container; a qualitative analysis was given on the influence to ventilation system. The wind speed of vertical draft impacted by hoisting container was measured, based on the actual measurement, six CFD computation models were set up, the pressure field and flow field were achieved. The findings indicated that, the moving-effect generated by hoisting container is the main cause resulting in the loss of pressure and pressure pulsation; its frequent movement causes the dynamic change of cross section of vertical draft leading to the dynamic change of ventilated resistance. The local resistance caused by hoisting container accounts for about 40 percent of the whole draft resistance; it is an important factor which impacts the stability of mine ventilation system. During the process of the movement of hoisting container, the flow field and the pressure field present complex change. Based on the comparison of the pressure field and flow field of six models, the results suggest that the more relative magnitude between the velocity of vertical draft and hoisting container is, the more marked of piston-effect is. The pressure pulsation leads to the reassign of air volume, and then impacts on the stability of ventilation system.