Influence of coal mine ventilation air methane inflow characteristic on heat extraction of heat exchanger embedded in packed bed

On the basis of the mathematical model which was validated by experiment,the influence of coal mine venti- lation air methane inflow characteristics on the heat extraction of the bed was studied by the numerical method. Numer- ical results show that the heat extraction rate of embedded heat exchanger in the packed bed decreases with the de- crease of the gas inlet mass velocity uniformity index,the gas unidirectional flow and increasing physical flow rate in bed and radiation heat transfer area resulted from packed honeycomb ceramic make that the decreasing scope of heat extraction rate of the packed bed embedded heat exchanger is larger than that of the empty bed heat exchanger when the gas inlet mass velocity uniformity index decreases same value;when gas inlet average mass velocity is constant,the heat extraction rate of the embedded heat exchanger decreases with the decrease of inlet gas temperature uniformity in- dex,and uneven temperature distribution results in uneven flow velocity distribution,so the decreasing scope of the em- bedded heat exchanger heat extraction rate caused by the uneven temperature distribution of inlet gas is bigger than that caused by the uneven flow velocity distribution when gas inlet average temperature and mass velocity are constant. For vertical oxidation bed,different buoyancy resulted from uneven temperature and the influence difference of buoyan- cy on flow caused by different gas inflow mode make the gas to be redistributed in gas collecting box,and make the heat extraction rate of the heat exchanger changed,the influence of gas inflow mode on the heat extraction rate is more and more obvious with the inlet gas average temperature increase.