微分进化算法应用于换热网络全局最优化

前言换热网络是过程系统中实现能量回收和高效利用的重要环节,其性能直接关系到整个系统的能量利用水平。目前,换热网络优化设计的方法主要分为三类,分别是夹点法[1-2]、数学规划法[3-4]与启发式方法[5-7]。     

Robust Simulation of Counterflow Moving Bed Dryers

Abstract

In this work, a robust and accurate strategy for simulating counterflow moving bed dryers is presented. A complete pseudo-transient phenomenological model for the process has been developed and the variable time is used as a continuation parameter. The desired solution is the final steady-state reached by the model. The code DASSL is used to perform the integration of the differential algebraic equation system and consistent initialization is achieved via a direct technique. The computational effort is surprisingly small comparing to those reported in the literature. Reasonable concordance between simulated and experimental results has been observed even though the mathematical model contains no adjustable parameters. Convergence problems have not been observed for all tested operating conditions, including those pointed by other authors as particularly difficult. The mathematical tool built is capable of making accurate predictions about the behavior of the equipment in affordable computing time and hence this constitutes an invaluable tool to study counterflow moving bed drying.     

Mathematical Modeling of Drying Processes Using Methods of the Nonequilibrium Thermodynamics and Percolation Theory

A twofold refinement of the basic mathematical model for describing a coupled heat and mass transfer taking place in porous media is presented. The common application of irreversible thermodynamics and fluctuation theory of phase transitions is proposed for calculating the moisture level and temperature. Instead of parabolic partial differential equations, hyperbolic type partial differential equations are used. The relaxation time constants, whose percolation state-dependence is also taken into account, are incorporated into this formalism. Some possible new research domains in mathematical and statistical physics are also indicated.     

Simulation study and kinetic parameter estimation of underground coal gasification in Alberta reservoirs

A new method is developed for the estimation of chemical reaction kinetics at high-pressure underground coal gasification from the field produced gas composition. This method combines a developed numerical forward model and field data to investigate uncertain parameters. The forward model is developed on the basis of a unique porous media approach that combines the effects of heat, mass transport, and chemical reactions to simulate the underground coal gasification in three-dimensional basis. The chemical reaction kinetics, that is limited to low pressure, is upscaled based on the available experimental data. A comprehensive sensitivity analysis is carried out to estimate the reaction kinetics and investigate the effect of various parameters, such as pressure, temperature, and reaction environment, on the produced gas composition. The novelty of the developed method is in its applicability as well as its ability to generate the chemical reaction kinetics that corresponds to the field under study. The advantage of the proposed technique is that the sensitivity of the model to different kinetic parameters can be investigated by a graphical method.     

高分子化学实验教学实践

本文在深入分析高分子化学实验课程的教学目的、具备一定教学实践的基础上,探讨了对备课、课堂教学、课后实验及考核三个环节的教学方法、教学观念,并据此进行了教学实践.结果表明,本研究所提出的教学理念是可行的,教师和学生达到了双赢的教学效果.     

国内外轿车子午线轮胎滚动阻力对比分析

试验研究轮胎负荷、充气压力和旋转速度对国内外不同轮胎生产企业195／65R15和205／55R16轮胎滚动阻力的影响。结果表明，对轮胎滚动阻力影响最大的因素是负荷，其次是旋转速度，最小的是气压；总体而言，米其林公司轮胎滚动阻力受各种使用条件的影响程度较小。     

Numerical Simulation of Oil‐water Hydrocyclone Using Reynolds‐Stress Model for Eulerian Multiphase Flows

A three‐dimensional oil‐water turbulent flow and oil separation process in a double‐cone liquid‐liquid hydrocyclone (LLHC) is numerically simulated using FLUENT software. The Euler‐Euler approach and Reynolds‐stress model are combined and adopted in this simulation to handle the challenging situation of anisotropic turbulent two‐phase flow with a higher volumetric ratio (over 10%) in the dispersed phase. It is visualized well in the simulation how separation, aggregation and shift of oil and water proceed in the LLHC. The oil separation efficiency is determined based on flow field and phase concentration distribution. The simulation is verified by comparing predicted and measured separation efficiency in the LLHC.     

搪瓷釉配方优化设计的通用方案

本文介绍了一种由计算机实现的配方优化设计方法,并给出了一个简单的通用优化方案。经实际运行证明,该方案是一个简单可行,易于推广的通用优化方案。     

电镀企业清洁生产审核第三部分电镀企业实施清洁生产的途径

介绍了电镀企业实施清洁生产的途径,采用替代电镀的清洁生产技术、逆流清洗技术、低毒无毒工艺、低浓度工艺,以及优化工艺规范,加强现场管理。     

从不规范设计书到系统逻辑控制器顺序功能流程图的设计

Today＇s automation industry is driven by the need for an increased productivity, higher flexibility, and higher individuality, and characterized by tailor-made and more complex control solutions. In the processing industry, logic controller design is often a manual, experience-based, and thus an error-prone procedure. Typically, the specifications are given by a set of informal requirements and a technical flowchart and both are used to be directly translated into the control code. This paper proposes a method in which the control program is constructed as a sequential function chart （SFC） by transforming the requirements via clearly defined intermediate formats. For the purpose of analysis, the resulting SFC can be translated algorithmically into timed automata. A rigorous verification can be used to determine whether all specifications are satisfied if a formal model of the plant is available which is then composed with the automata model of the logic controller （LC）.