Study On The Methods Of Reliability Engineering For Mine Ventilation System

Mine ventilation system is an important auxiliary system of production system, which is the precondition of normal production in mine. With the increasing of depth and the expanding scale of mine, it would be more complex and more difficult for ventilation system, therefore the reliability would be knocked-down even the airflow would get confusing. A failure even paralysis may happen because of the failure of a unit. The reliability of mine ventilation system is the guarantee of ventilation safety, elimination of potential accidents, prevention of gas and fire incidents, so it is necessary to study on the reliability of ventilation system. Throughout analyzing its reliability, reliability indices of subsystem could be calculated to find out hidden dangers of accidents, which can be prevented in advance, so as to reduce and prevent accidents of mine ventilation system for providing security for production.The unit reliability analysis was carried out firstly, based on this, the reliability analysis of subsystem was carried out. Lastly, measures to improve reliability were pointed out. The work can be mainly described as follows.On the basis of reliability analysis based on air quantity, another important factor, air quality is considered to define roadway reliability, comprehensively considering air quantity constrained conditions, toxic and harmful gas concentration constrained conditions. Under the condition of previous study, in which air-quantity distribution was considered to be normal distribution by experience, air-quantity distribution identification based on probability analysis diagram was given to calculate reliability of lognormal distribution.While previous study was concentrated on nodes-ergodicity method during the process of calculating minimal path sets for ventilation network reliability, ventilation network characteristic graph was used to recognize minimal path sets because of its intuition and high efficiency. Then the properties of sum of disjoint products was used to simplify reliability formula and calculate sensitivity coefficient.As for repairable property of ventilation dynamic system, the reliability model of main fan was set up by using the Markov Process theory, then the fault tree of local ventilation equipment was established to give the classification standard for safety grade and calculate the reliability. On the basis of fault tree, the methods of reliability allocation based on AGREE and economy were introduced to allocate reliability to the subsystems of local ventilation equipment.The air quantity stability of mine ventilation system was defines by the use of margin, whose discrimination method was given. The models of windage change, resistance change, air flow stability were put forward through three laws of mine ventilation system, and provide evidence for air quantity control. Furthermore, the approach to improve effectively stability of mine ventilation system was proposed.The soft of FLUENT was used to simulate wind in roadway with addition of air regulators, and the law of air-quantity distribution have been obtained. The calculating methods of reliability based on polynomial fitting and least square were given after regional reliability defined.The study in this paper is composed with network stream theory, reliability theory and numerical simulation. It serves as an important guiding role and has some reference value and practical meaning for further studying on the reliability of the mine ventilation system.