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81.
Yeong-Koo?YeoEmail author Ki-Seok?Hwang Sung?Chul?Yi Hong?Kang 《Korean Journal of Chemical Engineering》2004,21(4):761-766
In this study a model for the drying process in paper production plants was developed based on the mass and heat balances
around drying cycles. Relationships for the heat transfer coefficients between the web and the air as well as between the
drying cylinder and the web were extracted from the closed-loop plant operation data. It was found that the heat transfer
coefficients could be represented effectively in terms of moisture content, basis weight and reel velocity. The effectiveness
of the proposed model was illustrated through numerical simulations. From the comparison with the operation data, the proposed
model represents the paper plant being considered with sufficient accuracy. 相似文献
82.
An algorithm has been developed and tested for steady-state liquid-liquid extraction, using rectangular coordinates. It is capable of handling common types of stagewise contact, i.e., single stage extraction, multistage cross-current, and continuous countercurrent multistage extraction. The results depend on the nature of the extraction scheme and the extent of separation desired. While equilibrium data for some systems are stored in its data bank, the present portable computer simulator ( LIQEXT) has the flexibility of reading equilibrium data for other systems, as well as overriding stored data
Both design and rating cases can be performed. In the design mode, i.e., given the feed and solvent rates and the outlet concentration, it calculates the number of stages, the exit stream flow rates, and the concentration profile. In the rating ( or simulation) mode, i.e., given the feed and solvent rates, and the number of stages, it computes the exit streams flow rates and compositions, and the concentration profile. In both cases a graphical output of the concentration profile is produced, either on the screen or on a hard-copy plotter. 相似文献
Both design and rating cases can be performed. In the design mode, i.e., given the feed and solvent rates and the outlet concentration, it calculates the number of stages, the exit stream flow rates, and the concentration profile. In the rating ( or simulation) mode, i.e., given the feed and solvent rates, and the number of stages, it computes the exit streams flow rates and compositions, and the concentration profile. In both cases a graphical output of the concentration profile is produced, either on the screen or on a hard-copy plotter. 相似文献
83.
灰色预测补偿是一种对灰色系统进行白化的算法,该算法需要的信息少、计算量小。它可以克服常规PID控制存在超调的缺点。根据灰色PID控制算法,对系统不确定部分建立灰色模型,进行灰色预测补偿。通过仿真研究,该算法具有较强的鲁棒性,可以提高控制质量,减小控制系统的误差。 相似文献
84.
EVALUATION OF A METHOD FOR MEASURING MIXING TIME USING NUMERICAL SIMULATION AND EXPERIMENTAL DATA 总被引:10,自引:0,他引:10
Martin Lund n Olle Stenberg Bengt Andersson 《Chemical Engineering Communications》1995,139(1):115-136
A method for measuring mixing performance in large-scale vessels is investigated. The method is evaluated experimentally in a pilotscale reactor and by using a model based on the three-dimensional calculation of the flow field. The method is based on injection of a tracer and measuring the concentration with several detectors at different locations. The mixing performance is measured as the decay rate of the difference between the concentration at the detectors and the final concentration.
The model predicts a strong dependence on injection point. The assumption of a first-order decay rate of the concentration deviation is more appropriate for some injection points. 相似文献
The model predicts a strong dependence on injection point. The assumption of a first-order decay rate of the concentration deviation is more appropriate for some injection points. 相似文献
85.
The three-dimensional model of isothermal flow of power-law fluid in a coat-hanger die has been developed using finite element
method. The shape of coat-hanger die used in the present model was determined according to the previous analytical design
equation which is based on one-dimensional flow model in the manifold and the slot. Because uniform flow rate across the die
outlet is most important to achieve uniform thickness of extruded polymer sheet or film, flow rate distribution is mainly
examined to determine the valid process condition for the design equation as the design parameters are changed. The effects
of fluid property in terms of power-law index and process parameters not considered in one-dimensional design equation such
as die inlet size and the presence of land were analyzed. Results show that the manifold angle is the most influencing design
parameter on flow rate distribution. When the material of different power-law index from design value is processed, the change
of power-law index affects the uniformity of flow rate appreciably. 相似文献
86.
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89.
Three-dimensional (3-D), transient numerical simulations of the turbulent reacting flow in the vicinity of the initiator injection point of a low-density polyethylene (LDPE) tubular reactor using a large eddy simulation (LES) approach combined with a filtered density function (FDF) technique are presented. The numerical approach allows for detailed predictions of the turbulent flow field and the associated (passive and reactive) scalar mixing. The aim is to study the influence of the injector geometry and initiator injection temperature on the LDPE process in terms of product quality (average polymer chain length, and polydispersity) and process efficiency (such as initiator consumption). 相似文献
90.
We have solved both steady state and transient problems on the biofiltration of toluene vapor. The effect of inlet toluene
concentration and inlet gas-flow rate on the removal rate of toluene and the elimination capacity of a lab-scale biofilter
has been investigated. In this study, the effectiveness factor was a function of pollutant concentration. The dynamic solutions
show good agreement with experimental results. At an inlet toluene concentration of 100 ppm, the diffusion of toluene into
biofilm was obviously a rate determining step. Above 200 ppm, however, biofilm already showed full activity. The steady-state
simulation confirmed that the change of elimination capacity obtained by increasing only inlet toluene concentration was the
same as that obtained by increasing only flow rate of contaminated air. The maximum possible performance is about 20 g/m3h with no addition of nutrients. 相似文献