摘要
为研究煤内自然对流流动和换热的实质,在重力场中由高温壁面对煤内自然对流的驱动力进行了进一步分析。以高温壁面煤内自然对流为研究对象,采用整场求解法分析了高温壁面内煤的温度场和流场随Rayleigh数的变化。数值研究结果表明:强化传热时宜使高密度流体在上部,低密度流体在下部;削弱传热时宜使低密度流体在上部,高密度流体在下部;随着Ra增加,煤内对流增强且对流强度分布愈来愈不均匀;高温热源的不均匀性是影响对流形成的主要因素之一;当Ra很小时,当煤内对流作用较弱时,热的传输主要依靠传导作用,随着Ra数逐渐增大,对流作用增强,它成为热传输的主要动力。这为煤自然对流传热控制提供了一定的理论依据。
To research the essence of natural convection flow and heat transfer in coal,this paper further analyses the driving force to natural convection from high temperature wall in the gravitational field. The research object is the natural convection in coal inside the high temperature wall. Using the whole-field solution methed,it analyses the temperature field and flow field of coal inside the high temperature wall with the Rayleigh number changing. The research results indicate some conclusions. When enhancing heat transfer,the high density fluid should be made in the upper place while the low density fluid in the lower place. When weakening heat transfer,the low density fluid should be made in the upper place while the high density fluid in the lower place. When increasing Ra,the convection increases in coal, the convection intensity distribution becomes more nonuniform, the nonuniformity of high temperature heat source is the major influence factor of the formation of convection. When Ra is low,the convection in coal is relatively weak,heat transfer mainly relies on heat conduction. With Ra increasing,the convection is enhanced and becomes the major motive power of heat transfer. These conclusions provide certain theory basis for heat transfer control of natural convection.
出处
《中国地质灾害与防治学报》
CSCD
2013年第4期127-131,共5页
The Chinese Journal of Geological Hazard and Control
关键词
高温壁面
自然对流
煤
传热
high temperature wall
natural convection
coal
heat transfer
