Study On The Prediction Of Gas Emission Based On Gas Monitoring In Coalface

Since lots of gas emission sources appear in the coalface, and the gasconcentration is influenced by variable factors, the distribution of gas concentration incoalface is very complex, especially in the upper corner where usually exists thehighest gas concentration. Once in the upper coiner, there is a higher gasconcentration compared with the maximum safe limit, it will bring great risk to theproduction of coal mine. As a consequence, it makes a great difference in studying thedistribution of gas concentration.There’re some analyses about the main factors of gas emission in the coalface,some studies about the law of the gas emission based on researches of several gasemission sources, as well as the computational methods of the gas emission amount inthe second chapter. The third chapter includes the trend surface analysis method andits test method so as to reach the best trend surface. Apart from that, how to draw theisopleths map of the trend surface and the abnormal component are also included. Viathese two isopleths maps, it must be clearly known that the impact on gas emissionboth taken by the local geological factors and regional geological factors. The firsttwo chapters lay the theoretical foundation on the analysis of the law of the gasconcentration distribution of the whole coalface.In order to obtain the gas concentration of each observation surface of thecoalface, the wireless sensor network is been used. The wireless sensor gasconcentration measurement nodes are distributed in network topology structure tocollect the gas dates of each gas observation point. The wireless sensor gasmeasurement node mainly includes four single parts: ZigBee wireless communicationunit, data processing unit, sensor unit and power supply unit.According to the gas data of each observation point,1~5order trend surfacefitting equation models are founded, then the most suitable trend surface equationshould be got by the appropriate test of each trend surface model. Depending on theisopleths map and trend map drawn by surfer, analyses of the gas distribution incoalface from the overall perspective should be come out. Then, in the condition ofventilating current, the measurement nodes are distributed in different areas includingdifferent directions of the coalface, the cross section of the coalface, and the uppercorner. After that, it’s time to analyze the gas distribution in these cases and explainthe reasons based on the knowledge of fluid dynamic. Finally, the gas distribution of coalface in different wind speeds has been analyzed.