伴有二级不可逆反应管式反应器轴向扩散模型的近似计算

根据管式反应器返混程度不大这一事实，应用带大参数微分方程理论，对进行二级不可逆反应等温管式反应器的轴向扩散模型作了近似处理，提出了计算出口转化率的近似表达式。在较宽的参数范围内，用近似表达式对反应器出口转化率进行了计算；将近似表达式的计算结果与用打靶法计算的结果比较，二者吻合程度满意。通过计算还表明，利用该表达式进行近似计算，较之其它任何求解轴向扩散模型的数值计算方法具有计算简便的优点。

Approximate calculation for axial diffusion model in tubular reactor accompanied by a second-order irreversible reaction

Based on the fact that tubular reactor exhibit smaller degree of backmixing,approximate treatment for axial diffusion modelin isothermal tubular reactor accompanied by a second-order irreversible reaction is carried out employing theory of ordinary differentialequations with large parameter.An approximate expression for calculation the conversion at reactor outlet X_A is also derived.Calcula-tions of conversion at reactor outlet were made by approximate expression for a wider range of parameter.Furthermore,the results cal-culated by approximate expression are compared with shooting method.The agreement between both is satisfactory.The calculations al-so show that advantage of approximate expression is simple for calculation compared with any other numerical methods for solution of ax-ial diffusion model.