加油机小流量检定流量变量器

因为燃油加油机小流量检定时流量难以控制 ,很多检定人员在加油机周期检定或监督检查中 ,根本不检小流量。笔者设计的流量变量器 ,能很好地解决小流量检定时流量控制难题。而且方便实用 ,结构简单 ,易于自行加工。如图所示 ,变量器由橡胶密封圈、变量器体、夹紧座组成 ,直径Ф１ 与油枪头出油口外径相等 ,Ф２ 尺寸根据枪头出油口内径 ,按流量、直径比的比例确定 ,制成多种规格。检定时 ,只需根据检定流量的需要 ,选用合适的变量器 ,将油枪头装入变量器内 ,用螺栓坚固夹紧座即可。第一次检定为无效检定 ,从第二次开始进入正常检定程序。１ …     

流量测量孔板设计计算的几个问题

流量测量孔板以其结构简单，费用相对低廉和基本满足工业企业大多数流量测量要求的优点，目前仍然被广泛的应用。为此，就流量测量孔板设计计算时（无论是机算或手算）应考虑的几个问题加以讨论。1孔板的取压方式和取压方式的确定在进行孔板设计计算时，首先就要根据具体情况决定设计计算何种取压方式的孔板。1．1角接取压法角接取压包括夹紧环或法兰单独钻孔取压、环室取压。其特点是上下游取压孔中心至孔板前后端的间距备等于取压孔直径的一半，或取压孔在夹紧环或法兰内壁出口处的轴线分别与孔板上下游侧端面的距离等于取压孔直径的一半…     

串联孔板的流量-压降计算探讨

基于气液两相流体流过孔板的压降理论提出串联孔板节流元件的计算方法，用实验数据进行计算分析和间接验证。结果表明，计算值与实验值有较好的一致性，说明该方法用于串联孔板节流元件的设计计算有一定的可行性。     

适用于污脏和高黏度流体流量测量的楔形孔板

楔形孔板是一种具有测量污脏和高黏度介质特点的节流装置。楔形孔板和标准孔板的测量原理相同，在充满管道的流体流经节流件时。流速将在节流件处形成局部收缩，流速增加，静压力降低，在节流件前后产生静压差，根据能量守恒和流体连续性方程可以导出楔形流量孔板的流量方程式：     

天然气流量的标准孔板计量方法及影响其准确度因素简析

本文简析了天然气流量的孔板计量方法所存在的误差及影响因素，并提出了改进和预防的建议。     

水平管降膜蒸发器用制冷剂分布器设计参数讨论

针对水平管降膜蒸发器用筛板式制冷剂分布器的操作流量、开孔数目、开孔大小、孔口流出系数、分布均匀度等设计参数展开讨论,由此总结了制冷剂分布器各设计参数的确定方法,以及制冷剂分布器的理论设计思路;针对筛板式制冷剂分布器设计参数的讨论也适用于其他类型的分布器。     

流量积算仪用于能源计量时需探讨的几个问题

文章基于JJG 1003—2005《流量积算仪》检定规程和JJG640—1994《差压式流量计》检定规程对流量积算仪的生产和使用现状进行分析,给出几个合理使用的建议。     

Calculations of the temperature and flow field in a room ventilated by a radial air distributor

In ventilated or air-conditioned rooms optimal conditions of temperature, humidity and air velocity are required. In the present study the behaviour of a jet emerging from a radial plate distributor and the resulting air flow in the room were investigated. To predict the behaviour of the air flow a numerical scheme was used to solve the conservation equations for mass, momentum and energy with the k/ε-turbulence model. The numerical results are compared with available experimental data.     

变压吸附系统气流分布器结构的数值模拟计算及分析

建立分布器结构的数学模型,并采用此模型对目前小型医用制氧中应用的基本型吸附柱内部的速度场分布进行了数值计算分析。计算结果表明：吸附柱入口物流分配存在严重的不均匀性,同时发现改变分布器的结构可以有效改善吸附柱入口的物流分配。在此基础上,对两种不同型分布器结构进行了数值模拟,结果表明改进效果十分显著,采用这种现代数值图型研究方法所得出的结论对吸附柱气体分布器结构优化设计具有一定的指导意义。     

新型环流式气体分布器的设计与理论验证

简介常用气体分布器的种类及存在的缺陷,提出了一种新型环流式气体分布器,并以某空分项目的具体参数为依托,采用Fluent软件对新型环流式气体分布器在空冷系统水冷塔中的应用进行数值模拟,模拟结果表明新型环流式气体分布器具有较好的分布性能和较小的压降,适合工程应用。叙述模型的理论验证和模拟结果。     

液体融雪剂洒布管路系统动态仿真研究

 为了实现液体融雪剂洒布管路系统动态特性的精确描述以解决洒布过程的有效控制问题,根据洒布管路系统工作原理,运用基于功率键合图理论的AMESim软件,建立完整的洒布管路系统分布参数仿真模型进行动特性分析．结果表明：洒布管路压力流量分布均匀性不足,需进行优化;系统呈现低通滤波特性,泵源频率在40 rad/s以上的信号传递至喷口时衰减迅速;系统的瞬态与稳态性能对管路的各影响参数有不同的敏感度．通过物理实验与系统仿真的稳态结果对比,证明了AMESim洒布管路系统模型的有效性．研究所得方法和结论为液体融雪剂洒布管路系统元件匹配的参数化设计及控制调试提供了有力的理论支持．     

武钢60000m~3/h空分设备空冷塔激冷水分配器故障分析及处理

介绍了60000m3/h空分设备空冷塔激冷水分配器故障现象和故障具体部位的确认过程;分析了激冷水分配器故障的原因,最后简述了预防措施。     

Design Evaluation of Air Gap in a Ceiling Fan—A Simulation Case Study

Lower air gap in ceiling fan motors leads to higher rework at an assembly. It is suspected that inappropriate component design specifications may be the root cause. To resolve the issue and prevent worker dissatisfaction, a study is undertaken to evaluate the extent of air gap variation when components are produced as per design. First air gap is modeled as a function of different parameters of a fan assembly. The theoretical probability distribution of this modeled air gap function, though not impossible to obtain, is quite complex to derive. Thus this model is then used to generate data on air gap using Monte Carlo simulation. Analysis of the data shows that lack of process capability, not inappropriate design specifications, is mainly responsible for higher rework. The findings were discussed with management and were accepted. As a sequel to the study, a cost-benefit analysis is being undertaken for procuring new and improved machines.     

船用低噪声布风器设计与声学性能分析

在船舶与海洋平台中,空调管路系统噪声是舱室噪声的主要来源之一,风机与管路元件流动噪声通过管路系统与管口传递至舱室,布风器处于管路系统的末端,是连接管路系统与舱室之间的重要元件,在空调系统噪声控制中起重要作用.针对管路系统管口辐射噪声,在兼顾气动性能及声学效果基础上,提出新型低噪声布风器结构形式,采用数值模拟方法开展布风...     

Geometry,mechanical and ballistic properties of ADI material perforated plates

In this paper, austempered ductile iron has been evaluated as an alternative to steel for perforated plates applied in the ballistic protection of military vehicles. The austempering was performed in lower and higher austempering ranges in order to obtain two types of austempered ductile iron: one with a higher strength, and the other with a higher ductility. Perforated plates having two different thicknesses of 7 and 9 mm were mounted in front of basic armour and 12.7 × 99 mm armour – piercing incendiary ammunition was fired from 100 m. It was shown that the austempered ductile iron material austempered at a lower temperature has superior ballistic resistance, providing a full (five out of five armour – piercing incendiary shots stopped) ballistic resistance if combined with 13 mm basic armour plate. The thicker austempered ductile iron perforated plate provides more significant penetrating core damage, and therefore, lower basic plate damage. On the other hand, the thinner austempered ductile iron material perforated plate can be considered optimal due to its lower weight and higher mass effectiveness. In austempered ductile iron material austempered at a higher temperature, besides a lower hardness, bulk retained low-carbon metastable austenite transforms into martensite through strain induced mechanism, causing a partial brittle fracture.     

Novel method of air distributor design for enhancing bed stability and reducing impurities in gas–solid fluidized bed system

Coal plays a key role in the economic development of China. It is greatly significant to improve the efficient use of coal through high-efficiency dry separation. In this paper, a porous sponge was used to optimize the air distributor, and its fluidization characteristics were studied. Response surface methodology was used to study the collaborative optimization effects of gas velocity, separation time, and bed height on the fine coal separation. Gas velocity was the main factor which affects separation efficiency. When separation is in operation parameters, the yield and ash content were 65.48 and 10.89% as to the clean coal product and 9.24 and 80.47% as to the gangue product, respectively. Furthermore, the yield and ash content of middlings were 25.29 and 20.32%, respectively. The probable error, E, values were between 0.085 and 0.100?g/cm³. Using XRF and FTIR analysis, it was observed that the harmful elements and impurities in coal were reduced during the separation process.     

Numerical simulations and experimental measurements of the stress intensity factor in perforated plates

A numerical procedure, which combines two hybrid finite element formulations, was developed to analyse the stress intensity factors in cracked perforated plates with a periodic distribution of holes and square representative volume elements. The accuracy of the method in predicting the stress intensity factor was verified by a comparison with experimental measurements, carried out by a photoelasticity method, and by commercial finite element software. Several simulations were executed by varying both the crack length and the hole diameters, and the effects of the holes on the stress intensity factor are illustrated. The method shows high accuracy and efficiency, as small differences were observed when compared with the traditional finite element method, notwithstanding a strong reduction in degrees of freedom and mesh complexity.