MEASUREMENT TECHNIQUES AND DATA INTERPRETATIONS FOR VALIDATING CFD MULTI PHASE REACTOR MODELS

One problem associated with the use of Computational Fluid Dynamics(CFD) in reactor modeling is the proper validation of the models. Proper validation in this context means that the physical fluid dynamic model, the mathematical implementation and the data used for validation must be consistent. The present paper addresses this issue and to provide appropriate relations between experimental method and modeling approach

A critical review of currently used measurement techniques for characterizing multiphase now systems is presented. The interpretation of the data obtained from the various techniques is discussed as well as how these data can be used for validation of various CFD model formulations

Steady state models can be validated using time averaged data, making sure that the averaging time for the experimental data is long enough so that low frequency periodic oscillations also are evened out. If homogeneous systems are considered, then a volume average approach may be used for modeling, If the system cannot be considered homogeneous and steady, as is the most common case, then a dynamic ensemble averaging technique should be preferred. The validation of such models must be done with methods fast enough to resolve periodic fluctuating structures of interest. These methods are cumbersome and tedious to operate and the ergodic hypothesis may be invoked enabling the use of volume or time averaged data for the validation of ensemble averaged models.     

氨法脱碳系统再生能耗的研究

氨水溶液能够实现较高的CO2脱除率,具备较大的吸收能力,同时能够脱除烟气中SOx和NOx等酸性气体,近年来被认为是具有发展潜力的CO2吸收剂。普遍认为氨法再生过程的反应热能耗可降至26.88kJ.(molCO2)-1,远低于MEA能耗85kJ.(molCO2)-1。文中对比大量文献中的再生能耗数据,分析了其数据可靠性,理论计算和量热计实验测量低温下(35℃)氨水吸收CO2吸收热为60～70kJ.(molCO2)-1,并且随着CO2负载量增大无明显变化;高温下(80℃)初始吸收热热值约为60kJ.(molCO2)-1,随着CO2负载量增大而增大至120kJ.(molCO2)-1,然后再次减小至80kJ.(molCO2)-1。碳酸铵溶液吸收CO2过程吸收热测量实验也证实了氨水吸收CO2过程无法实现26.88kJ.(molCO2)-1低热值。和其他醇胺溶液吸收热热值相比,氨水溶液在降低能耗方面具有一定优势,但是优势不明显。