不同温度下煤粒瓦斯扩散特性试验研究与数值模拟

Experimental Study on Gas Diffusion Characteristics from Coal at Different Temperatures and Their Numerical Simulation

为探索温度对煤粒瓦斯扩散特性的影响,利用瓦斯吸附/扩散仪分别对不同温度下的等温吸附,同温同压初始条件下的煤粒升温瓦斯扩散,同压不同温初始条件下的恒温煤粒瓦斯扩散进行试验研究。试验结果表明:同温同压初始条件下的等效扩散系数随温度升高呈指数关系增大。同压不同温初始条件下的恒温综合扩散系数随温度升高呈先增大后降低的变化趋势。温度升高时,温度与初始吸附量对综合扩散系数具有相反的影响作用趋势。不同温度下,相同时间内的扩散量取决于二者的配比关系。建立温度影响下的理论扩散方程,数值模拟不同温度下的全过程扩散特征。计算结果表明:随着时间延长,各温度下的恒温扩散曲线呈多点交叉状态,符合试验关系。

In order to study effects of temperature on gas diffusion from coal granule, two different gas diffusion experiments were conducted using gas adsorption and diffusion equipment： the coal granule was in gas adsorption equilibrium under the same pressure and temperature conditions before gas diffusion experiment in different increased temperatures, and the coal granule was in gas adsorption equilibrium under the same pressure and different temperatures conditions before gas isothermal diffusion experiment. The experiment results show that the equivalent diffusion coefficient under the same pressure and tempera-ture condition increases exponentially with the increase of temperature. Under the same pressure the inte- grated diffusion coefficient first increases and then decreases with increasing temperature. With the increase of temperature, temperature and initial gas adsorption content inf/uenced the integrate diffusion coefficient reversely. The gas diffusion quantity for a given periode depends on the relation of temperature and initial gas adsorption content. At the same time, the theoretical equation for diffusion affected by tem- perature was created and the numerical simulation of the features of total diffusing process was carried out. The calculated results show that the isothermal diffusion curves for different temperatures have a crossing tendency and are in accord with the experiment results.