烧结矿竖罐内气固[火用]传递过程的实验研究

Experimental study on gas-solid exergy transfer process in sinter vertical tank

基于热力学第二定律和非平衡热力学理论,推导出烧结矿颗粒床层内气固[火用]传递特性的一般关系式,并借助自制气固传热实验平台,研究影响烧结矿床层内气固[火用]传递特性的主要因素及其影响规律。结果表明:平均[火用]传递系数随空气出口温度的升高而逐渐增加。当空气出口温度大于某一数值时,空气流量的增加和烧结矿颗粒直径的减小会导致平均[火用]传递系数的增加,反之亦然。对于某一特定的实验工况,随着颗粒雷诺数的增加,温度[火用]传递Nusselt数和平均[火用]传递Nusselt数逐渐减小,而压力[火用]传递Nusselt数逐渐增加,并且当空气出口温度低于某一数值时,平均[火用]传递Nusselt数会出现小于0的情况,对强化烧结矿床层内气固传热过程不利。

General relations of gas-solid exergy transfer processs in sinter bed layer were derived by applying second law of thermodynamics and non-equilibrium thermodynamics theory.The main factors influencing gas-solid exergy transfer process in sinter bed layer and their influence rules were studied with the help of experimental platform of homemade gas-solid heat transfer.The results show that,the mean exergy transfer coefficient gradually increases with the increase of air outlet temperature.When the air outlet temperature is greater than a given value,the increase of air flow rate and decrease of sinter particle diameter result in the increase of mean exergy transfer coefficient,and vice versa.For a certain experimental condition,the temperature exergy transfer Nusselt number and mean exergy transfer Nusselt number gradually decrease,and the pressure exergy transfer Nusselt number gradually increases with the increase of particle Reynolds number.The mean exergy transfer Nusselt number would be less than zero when the air outlet temperature is less than a given value,which is pointless for the gas-solid heat transfer process in sinter bed layer.