传热传质耦合影响松散煤体低温氧化的理论分析
Theoretical Analysis of the Heat and Mass Transfer Coupling Impacting on the Low-temperature Oxidation of Loose Coal
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摘要: 考虑到多孔介质中传热传质对松散煤体低温氧化温度场和浓度场的交叉耦合作用,对松散煤体低温氧化过程中氧的扩散与反应、热的传递建立数学模型,并对其无量纲化,得出表征传热传质耦合的无量纲扩散附加热效应准则数DCT和热附加扩散效应准则数STC。根据建立的数学模型可见:DCT与STC有加速热量传递和质量扩散的作用;松散煤体氧化初期,浓度差是热量传递的主要动力;松散煤体内部进入稳定氧化阶段后,热效应是气体的扩散的主要动力。Abstract: Considering the cross-coupling effect of the heat and mass transfer on the temperature and concentration field in the low-temperature oxidation of porous loose coal,mathematical models of oxygen pervasion and reaction,heat transfer were set up and dimensionless convection-dispersion-reaction equation was also established in the process of loose coal low temperature oxidation.The dimensionless diffusion-append heat effect similarity laws DCT and heat-append diffusion effect similarity laws STC were obtained.The DCT and STC have advantages to accelerate heat transfer and mass diffusion based on the numerical simulation.Important results were obtained that the concentration gradient is the main power of the heat transfer at the initial oxidation stage and the heat effect is the main power of gas mass pervasion during the stabilized oxidation stage.
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Keywords:
- loose coal /
- heat and mass transfer /
- coupling /
- dimensionless
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