DYNAMIC STABILITY OF VENTILATION SYSTEM OF AN OPERATING UNDERGROUND MINE, DURING OPERATION AND STANDSTILL OF MAIN FAN STATION

摘要

The object of research constitutes the ventilation system of an operating underground mine with two downcast shafts and one upcast shaft with exhaust main fan station. A physical model with the following lumped elements was thought out: dissipating, susceptible inertial, main natural ventilating energy and main fan station. A nonlinear mathematical model was reduced into a linear one adequate to operation and standstill of the main fan station - in the form of two homogenous differential linear second-order equations with constant coefficients - called equations of motion. Because of the lack of knowledge about the quantitative description of natural damping of vibrations propagated during the time lapse from the moment the state of equilibrium is suddenly thrown off, a variant-related approach was used comprising three variants determined by the length of the inertial element. Basing on general solutions of the mentioned equations of motion and variants, the following parameters were determined: a) parameters of linear physical models during operation and standstill of the main fan station, b) parameters of the ventilation system in non stationary state during operation of the main fan station, and c) parameters of this systems during the standstill of the mentioned station. Graphic own responses of the ventilation system to sudden unbalancing were given. Basing on the thermodynamic approach aerodynamic resistances of airways of the ventilation system were determined. The GIG gamma method was developed and using it the flow of mass streams in the ventilation system in the steady state during the standstill of the main fan station was calculated. It has been proven that the GIG gamma method is useful for ventilation systems both with and without diagonal airways. Dynamic stability indices, total relative resistance of the ventilation system during operation and standstill of the main fan station and its relation with the discriminate of the characteristic equation for the mentioned equations of motion were presented. On the basis of analysis or obtained results the conclusions were drawn.