Matlab在化工管路设计型计算的应用

化工管路设计型计算存在着公式多,解题难度大及计算复杂等特点,求解方法基本以迭代试差法为主,但在用常规手工计算求解过程中,因数据处理量过大而导致解题失误多、计算结果精确度低而不利于提高化工设计能力。本文分别以简单和复杂管路计算过程为例,阐明了Matlab在化工管路设计中的高效性和适用性。

多组份非理想溶液精馏工程模拟系统(Ⅱ)——设计型计算

本文改进了文[2]提出的局部模型结构,并将此用于常规塔系的设计型计算中。实例表明:这种结构的局部模型有迭代变量匹配合理,大范围收敛和节省内存等优点。

气—气热管换热器离散型设计计算方法研究

分析了气—气热管式换热器离散型设计计算方法产生误差的原因 ,在离散间壁式模型基础上 ,建立了考虑温度影响各种物性参数的新离散型设计模型。用平常运行的气—气热管式换热器的几何尺寸和实测数据 ,比较和分析了现存的各种设计计算方法所得理论值与实测值。结果表明新离散型设计计算方法更精确、更接近实际情况对实际计算有很好的理论指导作用。

用Excel 2000求解双组分精馏过程的设计型与操作型问题

以精馏过程的设计型与操作型问题为例,介绍Excel 2000的求解过程。计算过程及结果表明,利用Excel 2000解决精馏过程的设计型与操作型问题,不需编程,运算过程简单,结果可靠,具有易学、高效、快速、实用等特点。

化工原理教学中设计型问题的求解共性分析

有关化工原理的计算通常包括设计型计算和操作型计算两大类型,其中,设计型计算是化工原理教学的重点。本文以简单管路、换热器、吸收塔和精馏塔的设计型计算为例,总结了各种不同设备设计型计算的一般步骤,加深了学生对设计型计算过程的理解,有利于学生对化工原理设计型计算的掌握。

ZPW-2000A型自动闭塞计算机辅助设计系统

主要介绍了ZPW-2000A型无绝缘轨道电路自动闭塞计算机辅助工程设计系统的功能、结构及模块设计思想, 并对主要模块的实现提出了建议。

使用EXCEL进行PET装置热媒蒸发器的设计计算

通过对热媒蒸发器的特点进行分析,选取了合适的计算模型和公式,使用EXCEL电子表格的单变量求解和宏工具,方便地实现了热媒蒸发器的设计型计算。为实现程序自动迭代运算,文中还列出了通过EXCEL电子表格的数据处理功能对气相热媒和液相热媒参数在所使用的温度区间内进行连续化归纳的计算公式。

间歇精馏的计算

该文研究用正、反分段函数插值法及离散点下数值积分等数值方法进行间歇精馏的设计型计算和操作型计算;编写了通用的计算机程序;列举了应用实例.

组合梁相关设计问题的讨论

介绍了钢—混凝土组合梁的受力特性,从混凝土翼板的有效宽度,抗剪连接键,塑性理论计算对截面的要求等方面就组合梁设计中的一些问题进行了讨论,供工程设计人员参考。

换热器热效率的表达和应用

根据以冷、热流体基准的不同,定义了两种换热器的热效率(ε),在此基础上,推导得到了换热器热效率的四种不同的表达形式,并通过一个实例说明热效率-传热单元数法(ε-NTU法)在换热器操作型计算中的应用。

Photolithography Process Simulation for Integrated Circuits and Microelectromechanical System Fabrication

Simulations of photoresist etching,aerial image,exposure,and post-bake processes are integrated to obtain a photolithography process simulation for microelectromechanical system（MEMS） and integrated circuit（IC） fabrication based on three-dimensional （3D） cellular automata（CA）. The simulation results agree well with available experimental results. This indicates that the 3D dynamic CA model for the photoresist etching simulation and the 3D CA model for the post-bake simulation could be useful for the monolithic simulation of various lithography processes. This is determined to be useful for the device-sized fabrication process simulation of IC and MEMS.

Shrek:a dynamic object-oriented programming language

From a perspective of theoretical study, there are some faults in the models of the existing object-oriented programming languages. For example, C# does not support metaclasses, the primitive types of Java and C# are not objects, etc. So, this paper designs a programming language, Shrek, which integrates many language features and constructions in a compact and consistent model. The Shrek language is a class-based purely object-oriented language. It has a dynamical strong type system, and adopts a single-inheritance mechanism with Mixin as its complement. It has a consistent class instantiation and inheritance structure, and the ability of intercessive structural computational reflection, which enables it to support safe metaclass programming. It also supports multi-thread programming and automatic garbage collection, and enforces its expressive power by adopting a native method mechanism. The prototype system of the Shrek language is implemented and anticipated design goals are achieved.

Synthesis of fractal geometry and CAGD models for multi-scale topography modelling of functional surfaces

In order to support the functional design and simulation and the final fabrication processes for functional surfaces,it is necessary to obtain a multi-scale modelling approach representing both macro geometry and micro details of the surface in one unified model.Based on the fractal geometry theory,a synthesized model is proposed by mathematically combining Weierstrass-Mandelbrot fractal function in micro space and freeform CAGD model in macro space.Key issues of the synthesis,such as algorithms for fractal interpolation of freeform profiles,and visualization optimization for fractal details,are addressed.A prototype of the integration solution is developed based on the platform of AutoCAD's Object ARX,and a few multi-scale modelling examples are used as case studies.With the consistent mathematic model,multi-scale surface geometries can be represented precisely.Moreover,the visualization result of the functional surfaces shows that the visualization optimization strategies developed are efficient.

Designing an optimal stope layout for underground mining based on a heuristic algorithm

An optimal layout or three-dimensional spatial distribution of stopes guarantees the maximum profitability over life span of an underground mining operation.Thus,stope optimization is one of the key areas in underground mine planning practice.However,the computational complexity in developing an optimal stope layout has been a reason for limited availability of the algorithms offering solution to this problem.This article shares a new and efficient heuristic algorithm that considers a three-dimensional ore body model as an input,maximizes the economic value,and satisfies the physical mining and geotechnical constraints for generating an optimal stope layout.An implementation at a copper deposit demonstrates the applicability and robustness of the algorithm.A parallel processing based modification improving the performance of the original algorithm in terms of enormous computational time saving is also presented.

Design and optimization of exhaust gas aftertreatment system for a heavy-duty diesel engine

Diesel engines meeting the latest emission regulations must be equipped with exhaust gas aftertreatment system,including diesel oxidation catalysts(DOC),diesel particulate filters(DPF),and selective catalytic reduction(SCR).However,before the final integration of the aftertreatment system(DOC+DPF+SCR)and the diesel engine,a reasonable structural optimization of the catalytic converters and a large number of bench calibration tests must be completed,involving large costs and long development cycles.The design and optimization of the exhaust gas aftertreatment system for a heavy-duty diesel engine was proposed in this paper.Firstly,one-dimensional(1D)and threedimensional(3D)computational models of the exhaust gas aftertreatment system accounting for the structural parameters of the catalytic converters were established.Then based on the calibrated models,the effects of the converter’s structural parameters on their main performance indicators,including the conversion of various exhaust pollutants and the temperatures and pressure drops of the converters,were studied.Finally,the optimal design scheme was obtained.The temperature distribution of the solid substrates and pressure distributions of the catalytic converters were studied based on the 3D model.The method proposed in this paper has guiding significance for the optimization of diesel engine aftertreatment systems.

Study of the ship design process model for collaborative design

The ship design process model is the basis for developing the ship collaborative design system under network environment.According to the characteristics of the ship design, a method for dividing the ship design process into three layers is pat forward, that is project layer, design task layer and design activity layer, then the formalized definitions of the ship design process model, the decomposing principles of the ship design process and the architecture of the ship collaborative design (SDPM) system are presented. This method simplifies the activity network, makes the optimization and adjustment of the design plan convenient and also makes the design process easier to control and change, at last the architecture of the ship collaborative design system is discussed.

Theory of gas extraction from coal seams and its use

Gas extraction is one of the main measures of control and use of gas of coal mines. At present, the design method is under the experimental period and do not satisfy the need of practice. In this paper, the theory of gas extraction of coal seams based upon Darcy law was studied. Mathematical model of gas extraction of coal seams was established and two kinds of solv- ing approaches based on computer software and linear approximation were given. The rightness and the validities of the model were examined with a practical example. Results obtained can be used to determine and optimize the parameters related etc.

Application of a transversely isotropic brittle rock mass model in roof support design

Accurate modelling of the potential failure modes in the rock mass is an essential task towards a robust design of roof support systems in coal mines.The use of generalised rock mass properties based on averaged properties(e.g.Hoek-Brown model) has been found to limit the capability to reproduce the actual rock mass behaviour which may include a wide range of interacting and complex failure mechanisms such as shear and tension fracturing of the intact rock and shear and separation of pre-existing discontinuities,including re-activation.Recent studies have also shown that traditional models,such as the Mohr-Coulomb,may not accurately describe the behaviour of the intact rock,particularly for stress induced failures where spalling and slabbing are observed.This is mainly due to the cohesion and friction components of the shear strength of the intact rock not being mobilised at the same rate with strain-softening of the former component playing an essential role in the post peak behaviour.In addition,coal measure rocks are often transversely isotropic,both by way of the preferred orientation of clay particles within the finer grained lithology and by bedding textures and bedding partings,and this is often ignored in computer simulations.A newly developed transversely isotropic brittle rock mass model is applied in the simulation of a hypothetical and simple roadway development.A Cohesion Weakening-Friction Strengthening(CWFS) approach is adopted to describe the intact rock where the mobilisation and strain-softening of the two shear strength components are linked to plastic deformation.The impacts of anisotropy and brittle rock on the development of the excavation disturbed zone or height of softening,as often referred to,are investigated and their implication in the roof support design discussed.

Pattern Specialization Based on Partial Evaluation

Design pattern enables software architecture generality and reusability, but which depresses the high performance. The pattern specialization was built on partial evaluation technology to reduce the overheads of design pattern. The design patterns were classified to extract the common features, and the corresponding pattern specializations were constructed. In the pattern specialization, the optimization opportunities were identified, and the specialization methods and conditions were described. The syntax of binding time analysis was defined, and the semantic depicted the invariant of usage context. The virtual invocation and dispatch were eliminated, which enhances the running efficiency. This pattern specialization is a high-level specialization for improving the performance of software aimed at design level that is orthogonal with the low-level code optimization.

Technical illustration based on 3D CSG models

This paper presents an automatic non-photorealistic rendering approach to generating technical illustration from 3D models. It first decomposes the 3D object into a set of CSG primitives, and then performs the hidden surface removal based on the prioritized list, in which the rendition order of CSG primitives is sorted out by depth. Then, each primitive is illustrated by the pre-defined empirical lighting model, and the system mimics the stroke-drawing by user-specified style. In order to artistically and flexibly modulate the illumination, the empirical lighting model is defined by three major components: parameters of multi-level lighting intensities, parametric spatial occupations for each lighting level, and an interpolation method to calculate the lighting distribution over primitives. The stylized illustration is simulated by a grid-based method, in which we ‘fill’ the desirable pictorial units into the spatial occupation of CSG primitives, instead of “pixel-by-pixel” painting. This region-by-region shading facilitates the simulation of illustration styles.