To explore the coupled effect of heat and mass transfer,the coupled model of heat and mass transfer for a fixed bed adsorption process was established according to the Soret effect and the Dufour effect theory.Numeric...To explore the coupled effect of heat and mass transfer,the coupled model of heat and mass transfer for a fixed bed adsorption process was established according to the Soret effect and the Dufour effect theory.Numerical analysis methods were adopted to discuss the influences of heat transfer coefficients,mass transfer coefficients,and the coupled effect of heat and mass transfer on the fixed bed adsorption process respectively.Results have shown that heat transfer coefficients have little effect on mass transfer.To the degree of influence on the temperature field,the greatest is the heat transfer coefficient,followed by the axial thermal conductivity,the smallest is the external heat transfer coefficient.The mass transfer coefficients have some impact on the heat transfer and the mass transfer effect caused by the temperature gradient is more obvious than the heat transfer effect caused by the concentration gradient.展开更多
A porous medium involving endothermic chemical reaction was studied by using the irreversible flow processes thermodynamics method.A mathematical model describing the coupled irreversible processes of heat transfer,ma...A porous medium involving endothermic chemical reaction was studied by using the irreversible flow processes thermodynamics method.A mathematical model describing the coupled irreversible processes of heat transfer,mass transfer and chemical reaction in porous medium was established,and the model was solved numerically by applying the finite volume implicit method.By taking the decomposition of limestone as a case,the effects of the Soret and the Dufour phenomena were analyzed.The results showed that when the Peclet module was lower,the effects of the Soret and the Dufour phenomena could not be ignored.As a result,the product gas and the quantity of heat of gas in the porous medium would come through the reactor much quicker,and the concentration of the product gas,the temperature of gas flow and the solid conversion degree would be lower.展开更多
文摘To explore the coupled effect of heat and mass transfer,the coupled model of heat and mass transfer for a fixed bed adsorption process was established according to the Soret effect and the Dufour effect theory.Numerical analysis methods were adopted to discuss the influences of heat transfer coefficients,mass transfer coefficients,and the coupled effect of heat and mass transfer on the fixed bed adsorption process respectively.Results have shown that heat transfer coefficients have little effect on mass transfer.To the degree of influence on the temperature field,the greatest is the heat transfer coefficient,followed by the axial thermal conductivity,the smallest is the external heat transfer coefficient.The mass transfer coefficients have some impact on the heat transfer and the mass transfer effect caused by the temperature gradient is more obvious than the heat transfer effect caused by the concentration gradient.
文摘A porous medium involving endothermic chemical reaction was studied by using the irreversible flow processes thermodynamics method.A mathematical model describing the coupled irreversible processes of heat transfer,mass transfer and chemical reaction in porous medium was established,and the model was solved numerically by applying the finite volume implicit method.By taking the decomposition of limestone as a case,the effects of the Soret and the Dufour phenomena were analyzed.The results showed that when the Peclet module was lower,the effects of the Soret and the Dufour phenomena could not be ignored.As a result,the product gas and the quantity of heat of gas in the porous medium would come through the reactor much quicker,and the concentration of the product gas,the temperature of gas flow and the solid conversion degree would be lower.
