分子筛的操作与维护

简介了分子筛净化流程空分装置中自动化程度较高的分子筛的结构、工作原理及流程,详细阐述了分子筛在DCS控制系统的操作与维护。     

SY-40强力旋压机床程序控制原理

根据对SY-40强力旋压机床设计和研制的经验,介绍了旋压机床程序控制原理的关键内容,并以典型旋压零件——标准椭球封头为例,说明其建立数学模型的详细过程,对旋压机床的研制和开发有一定的参考意义。     

数字射线检测技术专题(一)——概述

概括介绍了数字射线检测技术的发展情况、物理基础与标准制定情况。     

经济管径与阻力损失

介绍选择经济管径的计算方法,编制了计算程序,并将计算结果与实际运行相比较,对高粘度液输送的阻力计算提出了新的见解。     

巧用CL-02DS中文设定显示单元

本文介绍了利用CL－02DS中文设定显示单元，配合程序设计，使之实现记录功能。     

Effect of some BED blends on the equivalence ratio, exhaust oxygen fraction and water and oil temperature of a diesel engine

Nowadays, natural-based oxygenated fuels, especially biodiesel and ethanol, have been considered as substitutes for fossil fuels. Because of relatively lower energy content of oxygenated fuels, it is necessary to blend them with fossil ones. In this research, authors conducted an investigation on some BED blends to determine and compare their effects on equivalence ratio, exhaust oxygen fraction and water and oil temperature in a diesel engine. For this purpose, 18 different blendes of ethanol and biodiesel with net diesel fuel were tested in a MT4-244 engine¹ considering two engine speeds in full load condition. In almost all samples the equivalence ratio decreased with increasing of biodiesel and ethanol percents. Exhaust oxygen fraction in all of samples increased with increasing of biodiesel and ethanol percents, whereas the engine water and oil temperatures slightly reduced.     

Idle characteristics of a hydrogen fueled SI engine

This paper investigates the effect of the equivalence ratio Φ and ignition advance angle θ_i on idle characteristics of a turbocharged hydrogen fueled SI engine. The experimental data was conducted under various operating conditions including different Φ and θ_i. It is found that, the ignition advance angle at MBT point decreases gradually with the equivalence ratio increasing from 0.4 to 0.9. Indicated thermal efficiency decreases as Φ increases. Emissions of NOx increase as Φ increases. When Φ is kept constant, the stated emissions increase as θ_i increases. During idle conditions of a hydrogen fueled engine, a lean mixture with an Φ less than 0.4 is suitable, and the θ_i should be increased appropriately. The maximum cylinder pressure rises with an increase of Φ and θ_i. The trend of the maximum rate of pressure rise is similar at different Φ. Only under the conditions of Φ = 0.4 and θ_i < 10 °CA, the maximum pressure rise rate remains almost unchanged.     

Further study on the ignition delay times of propane–hydrogen–oxygen–argon mixtures: Effect of equivalence ratio

Using a shock tube facility, measurements on ignition delay times of propane/hydrogen mixtures (hydrogen fraction X_H2 is from 0% to 100%) were conducted at equivalence ratios of 0.5, 1.0 and 2.0. Results show that when X_H2 is less than 70%, ignition delay time shows a strong Arrhenius temperature dependence, and the ignition delay time increases with the increase of equivalence ratio. When X_H2 is larger than 95%, the ignition delay times do not retain an Arrhenius-like temperature dependence, and the effect of equivalence ratio is very weak when the hydrogen fraction is further increased. Numerical studies were made using two selected kinetic mechanisms and the results show that the predicted ignition delay times give a reasonable agreement with the measurements under all test conditions. Both measurements and predictions show that for mixtures with X_H2 less than 70%, the ignition delay time is only moderately decreased with the increase of X_H2, indicating that hydrogen addition has a weak effect on the ignition enhancement. Sensitivity analysis reveals the key reactions that control the simulation of ignition delay time. Further investigation of the H-atom consumption is made to interpret the ignition delay time dependence on equivalence ratio and X_H2.     

采用经济型数控机床加工车轮

针对车辆制造厂家需要小批量、技术要求高的车轮的实际情况，提出了在经济型数控机床上加工车轮的设想，设计了新的、合理的加工工艺流程及专用工装夹具和刀具，并编制NC加工控制程序，加工出了符合图纸技术要求的合格车轮。     

基于Solid Edge的三维模型通用参数化程序设计方法

阐述了基于三维CAD系统的三维模型参数化设计方法 ,提出了用设计变量作为三维模型样板与参数化设计程序相联系的纽带 ,从而大大提高了程序设计效率和程序的通用性。以SolidEdge三维软件为例 ,采用VB开发技术 ,实现了三维模型的通用参数化程序设计