低温取芯过程热传递方式的数值模拟和实验研究

Numerical simulation and experimental study on way of heat transfer during low temperature coring process

为了研究热量在低温取芯过程中传递的方式,以型煤为研究对象,使用自制低温取芯模拟装置,通过实验并结合数值模拟,对低温取芯过程热量传递方式进行研究,进而分析煤芯温度的变化规律。研究结果表明:甲烷的存在降低了煤样的热交换速率,使煤芯温度变化滞后于煤样罐壁温度变化;煤体内部温度分布存在差异,煤样中心轴线不同半径处的圆柱面构成变温过程的等温面,在降温过程,热量沿径向由煤样内部向外部传递,升温过程,热量沿径向由外部向内部传递;低温取芯过程热量传递同时存在3种方式:热传导、热对流,煤体表面与罐体内壁表面之间的热辐射,以热传导方式为主。

In order to study the way of heat transfer in the low temperature coring process,the corresponding experiments were carried out by using the self-made simulation device of low temperature coring with the briquette as the research object and combined with the numerical simulation,thus the change laws of coal core temperature were analyzed. The results showed that the existence of methane decreased the heat exchange rate of coal samples and made the change of coal core temperature lag behind the temperature change of coal sample tank wall. The internal temperature distribution of coal body existed the difference,and the cylindrical surfaces at the positions of different radius from the central axis of coal samples constituted the isothermal surfaces of temperature changing process. During the cooling process,the heat transferred from the interior of coal samples to the outside along the radial direction,and during the heating process,the heat transferred from the outside to the interior along the radial direction. There were three ways of heat transfer in the low temperature coring process at the same time,namely the heat conduction,the heat convection,and the heat radiation between the surface of coal body and the surface of tank internal wall,among which the heat conduction was the main way.