| Under the background that national economy is developing rapidly and mineral resources are exploited energetically today, safety problems become very prominent in mining production, especially in underground mines. Safety problems often happen in a mine ventilation system, e.g. less airflow, return airflow, stagnant airflow, and circular airflow and so on, which menace safe production in underground mines directly. At present, there are many methods and techniques for modulation and control of airflow in underground mines, but those are often restricted by certain condition. It is difficult to carry out the control of airflow. Based on searching many documents in the world, and depending upon the basic theory of air flow underground mine and the theory of air partition-free auxiliary fans, theoretical models on cutting off airflow, ejecting wind flow and increasing resistance of airflow by air curtain with multi-parallel fans were established in this paper. Also the relevant factors were analyzed when air curtain with multi-parallel fans operates. Accordingly, every theoretical model was analyzed depending on MATLAB by computer simulation. In addition, on the foundation of testing characteristics of air curtain with single fan in the lab, cutting off airflow, ejecting airflow and increasing resistance of air curtain with multi-parallel fans in the main transport drifts in underground mines were tested and they were applied at 2~# mining field of JNMC, Longshou Mine, Anqing Copper Mine of TNMC, and Makeng Iron Mine respectively.Main research fruits include:1. Theoretical models of multi-function air curtain for mine were established and their relevant factors were analyzed. These models are: cutting off airflow of air curtain with multi-parallel fans in a drift, ejecting airflow of air curtain with single fan and multi-parallel fans in a drift, increasing resistance for reducing airflow of air curtain with single fan and multi-parallel fans in a drift.2. Three-dimension figures of all the theoretical models of multi-function air curtain were drawn by MATLAB, and characteristics of air curtain effective pressure and ejecting wind volume were analyzed with the changing of other factors.3. Characteristics of air curtain were tested and analyzed through changing cross sectional area of test tunnel, fixing angle of fan's vane, power of fan and so on in the lab. The optimum technical parameters of air curtain were obtained.4. Adopting comparing test, 3 functions of multi-function air curtain for controlling air flow were investigated at 2~# mining field of JNMC and Longshou Mine.5. Application of air curtain with functions of ejecting airflow and increasing resistance for reducing airflow was tested to prevent the skip shaft from icing in winter and return airflow in Anqing Copper Mine.Research results indicate that, at the same cross section in a drift with large cross sectional area and large air pressure difference, multi-parallel air curtain can not only cut off airflow effectively, but also can eject airflow to increase airflow rate of a drift, control the airflow direction, increase resistance and prevent icing in a drift where water constantly drips in winter effectively. The research fruit provides a new effective approach for solving the problem on airflow control in the main transport drift where ventilation structures can not be installed. The investigation brings economic and social benefits for mine prominently. It has wide prospect application field.Main innovations are as follow:(1) Multi-function theoretical models of air curtain for mine were established. Onthe foundation of simulation analysis and experiment in the lab, application practice was developed prominently on the respect of controlling airflow in mines.(2) Multi-fans in parallel connection and work at the same drift section were conducted, which forms air curtain with multi-parallel fans. It can cut off airflow, eject airflow and increase resistance of a drift. The technical problem of modulating airflow a drift with large across section area and large air pressure difference was solved.(3) Application of air curtain was studied to prevent icing in a skip shaft where water constantly drips in winter.(4) Application of air curtain was studied to control airflow return in the transport drift and adjust airflow distribution in underground mines effectively.
|
PDF Full Text Request