环形串联直缸发动机配气系统设计

环形串联直缸发动机具有功率密度高、惯性力小等诸多优点,但其运行时气缸转子始终绕输出轴周向转动,使得传统发动机静态的配气方法不再适用。因此,研究设计一种能够满足该型发动机进排气需求的新型配气系统意义重大。针对该型发动机独特的环形串联结构和差速运动特性,研究了各转子气缸的容积变化规律,分析了各转子气缸进排气相位与转子转角之间的关系,创新设计了一种基于气道复用的动态位置配气系统。根据二冲程发动机配气方案设计加工了配气系统零部件,并通过高压气动实验完成了对该型发动机的动态进排气过程。实验结果表明,当给定外加驱动气压0.25 MPa时,发动机能够以约200 r/min的速度稳定运转,有效验证了该配气系统的可行性。

纯电动越野赛车高压电气系统设计

纯电动越野赛车的高压电气系统设计是确保车辆具有良好性能和可靠性的关键。该文基于纯电动越野赛车动力参数及性能要求,论述高压电气系统的设计思路,包括电池包设计、高压分线盒设计、电控单元设计,对系统结构关键参数进行设计与选择,并对赛车进行不同工况下的试验验证。结果表明,该文设计的纯电动越野赛车高压电气系统能够满足比赛规则对于赛车的性能要求,设计合理。

万家寨引黄工程总干二级泵站气系统设计

万家寨引黄工程总干二级泵站为地下式厂房泵站,气系统是泵站辅助设计中重要的组成部分。介绍了气系统设计中空压机和气罐选择与布置,管路、仪表、阀门的布置,以及压缩空气系统的自动控制设计。

消声元件在汽车进气系统设计中的运用研究

汽车是现代十分常见的交通工具,其给人们的生活带来了巨大便利,但同时也造成了一些困扰,例如噪声问题。汽车在运行当中,其进气系统或其他机组的运行,必然会因为部件运动而出现一些声响,这些声响的分贝普遍不高,但在长时间影响下依旧会给驾驶者造成不良体验,所以在现代汽车系统设计当中十分提倡消声元件的运用。本文为了了解消声元件在汽车进气系统设计中的运用,将展开相关分析工作。

上海光源光束线液氮单色器真空夹层抽气系统设计

针对上海光源部分光束线液氮单色器真空夹层真空度下降、液氮管路冷量损失引发夹层外壁冷凝滴水、结霜等威胁运行安全的问题,设计了具有真空度反馈控制和定时启动功能的自动抽气系统。模拟计算了夹层外壁不同真空度下的冷量损失及温度分布变化规律,确定了系统工作的真空度阈值等参数。设计的抽气系统当前在束线液氮单色器上运转良好,有助于束线稳定运行。

浅谈污水处理曝气系统设计及设施安装

本文简要阐述了污水处理曝气系统的设计原理，设施的种类及其安装特性。

客车发动机进气系统的设计

介绍客车发动机用干式空气滤清器的选型、进气系统原始进气口的设计及空气滤清器的布置方式和进气管路的设计原则等。

客车发动机进气系统的设计

介绍客车发动机用空气滤清器的选型、进气系统原始进气口的设计及空气滤清器的布置方式和进气管路的设计原则等,并指出一些进气系统设计及布置方面的常见错误。

山东魏桥8×240t/h锅炉烟气脱硫系统设计简介

山东魏桥8×240t/h锅炉烟气脱硫系统工程属于电厂改造项目,存在场地紧张、分散,改造工作量大且系统要求高等难点。本文重点介绍了烟气脱硫系统设计情况,并对创新和设计难点进行了阐述,以便为国内同类工程提供参考作用。

面向抛光打磨工艺过程的机器人成套系统设计

使用埃夫特型号为ER50的机器人,夹取水龙头工件在砂带机配合下对60#、180#、400#及800#砂带进行打磨。该文先对机器人抛光打磨工艺系统的总体方案进行设计,再对砂轮机的相关结构进行分析设计,满足抛光打磨的功能需求。针对打磨的水龙头工件,设计了夹具利用气缸实现工件的夹紧,在结构方面,即满足了打磨位姿的需要,也避免了夹具与其他设备的干涉。气路与电控系统设计主要是控制力反馈(力平衡)气缸和砂带张紧气缸的压力及动作,通过机器人抛光打磨进行自动化作业,从而降低成本。为了满足客户的需求,需要计算定量加工水龙头工件的时间,从而得出哪种生产方式的效率最高。人工打磨抛光成本很高但加工精度却不高。采用机器人对零部件抛光打磨可以大大降低其表面粗糙度,提高其表面质量。

Property Analyses and Experiment Studies of a Kind of PWM System

The properties and the design of PWM systems are discussed. The relations among the orifice areas of the valves, initial times and the rate of piston areas are deduced. Also a PWM system is designed and some experiments are done. The experiment results agree with those of theory analyses. It can be shown that the relations are correct and the conclusion of theory analyses is reasonable.

System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system

As an environmentally harmless and feasible alternate refrigerant, CO 2 has attracted worldwide attention, especially in the area of automobile air conditioning (AAC). The thermal property of CO 2 and its trans critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO 2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO 2 AAC system.

Long-term variability of air temperature and precipitation conditions in the Polish Carpathians

Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years.Climate change is most evident in the foothills;however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians,which reach approximately 350 meters, on average,what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.

Investigation on a vertical radial flow adsorber designed by a novel parallel connection method

Due to the increasing global demand for industrial gas, the development of large-scale cryogenic air separation systems has attracted considerable attention in recent years. Increasing the height of the adsorption bed in a vertical radial flow adsorber used in cryogenic air separation systems may efficiently increase the treatment capacity of the air in the adsorber. However, uniformity of the flow distribution of the air inside the adsorber would be deteriorated using the height-increasing method. In order to reduce the non-uniformity of the flow distribution caused by the excessive height of adsorption bed in a vertical radial flow adsorber, a novel parallel connection method is proposed in the present work. The experimental apparatus is designed and constructed; the Computational Fluid Dynamics(CFD) technique is used to develop a CFD-based model, which is used to analyze the flow distribution, the static pressure drop and the radial velocity in the newly designed adsorber. In addition, the geometric parameters of annular flow channels and the adsorption bed thickness of the upper unit in the parallelconnected vertical radial flow adsorber are optimized, so that the upper and lower adsorption units could be penetrated by air simultaneously. Comparisons are made between the height-increasing method and the parallel connection method with the same adsorber height. It is shown that using the parallel connection method could reduce the difference between the maximum and minimum radial static pressure drop by 86.2% and improve the uniformity by 80% compared with those of using the height-increasing method. The optimal thickness ratio of the upper and lower adsorption units is obtained as 0.966, in which case the upper and lower adsorption units could be penetrated by air simultaneously, so that the adsorbents in adsorption space could be used more efficiently.

Thermodynamic design of a cascade refrigeration system of liquefied natural gas by applying mixed integer non-linear programming

Liquefied natural gas(LNG) is the most economical way of transporting natural gas(NG) over long distances. Liquefaction of NG using vapor compression refrigeration system requires high operating and capital cost. Due to lack of systematic design methods for multistage refrigeration cycles, conventional approaches to determine optimal cycle are largely trial-and-error. In this paper a novel mixed integer non-linear programming(MINLP)model is introduced to select optimal synthesis of refrigeration systems to reduce both operating and capital costs of an LNG plant. Better conceptual understanding of design improvement is illustrated on composite curve(CC) and exergetic grand composite curve(EGCC) of pinch analysis diagrams. In this method a superstructure representation of complex refrigeration system is developed to select and optimize key decision variables in refrigeration cycles(i.e. partition temperature, compression configuration, refrigeration features, refrigerant flow rate and economic trade-off). Based on this method a program(LNG-Pro) is developed which integrates VBA,Refprop and Excel MINLP Solver to automate the methodology. Design procedure is applied on a sample LNG plant to illustrate advantages of using this method which shows a 3.3% reduction in total shaft work consumption.

Design and application of electrical fire monitoring system in mining industry

To protect mining areas from electrical fire, it is very important to install electrical nre momtormg system to ensure safety in development of mineral resources and for buildings. In this paper, design for electrical fire monitoring and detection system with optional sensor modules has been proposed. In addition, necessity and suitability of electrical fire monitoring and detection system with optional sensor modules in mining areas have been reviewed. The designed electrical fire monitoring and detection system suit- able for work environment of mining industry is composed by host-computer monitoring software and slave-computer detectors. Monitoring detectors are manufactured by using embedded technology. Exter- nal shells deployed have superior enclosure performances and explosion-proof properties. It is easy to install and maintain the system. In general, the system has reached, or even exceeded standards specified in national standards for performances and appearances of such devices. Test results show application of electrical fire monitoring and detection system can effectively enhance monitoring intensity over the mining areas and provide reliable guarantee to ensure orderly development of mineral resources and to protect physical and property safety of citizens in these areas.

Design and Analysis of PV Hybrid System for Isolated Household Electrification

This paper describes a design method and construction of a PV hybrid system for household electrification in remote area which has typical important electrical loads for daily life such as television, refrigerator, electric fan, coffee maker, and radio. The paper presents the design method which is a short and correct method for the PV Hybrid system design. The result of the proposed design method is finally simulated by Homer software to optimize and prove the result. From the simulation, the output shows that the proposed method is proper for using to design the sizing of PV hybrid system. After the design, a PV hybrid system is constructed accordingly to the system design. A PV hybrid prototype is constructed as a small house which is specially constructed for demonstration of the proposed system. The PV hybrid system therefore has the size of PV 1.8 kWp, battery 20 kWh, and diesel generator 3 kW. After a long implementation of the system, the results of monitored data show that the designed PV hybrid system can deliver the power to the house continually 24 hours as it is originally designed. This can ensure that the proposed method of PV hybrid system design is correct and can be used for design the PV hybrid system for electrical utility in the remote area where has no an electric grid.

Design of an Expert Control System for Biogas Fermentation Process

Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.

Nonlinear State Feedback Control of PEM Fuel Cell Systems

In this paper, the nonlinear state feedback controller has been developed to control the pressures of the oxygen and the hydrogen in the PEM（Proton Exchange Membrane） fuel cell system. Nonlinear model of the PEM fuel cell system was introduced to study the design problems of the state observer and model based controller. A cascade observer using the filtering technique was used to estimate the pressure derivatives of the cathode and the anode in the system. In order to estimate the pressures of the cathode and the anode, the sliding mode observer was designed by using these pressure derivatives. To estimate the oxygen pressure and the hydrogen pressure in the system, the nonlinear state observer was designed by using the cathode pressure estimates and the anode it. These results will be very useful to design the state feedback controller. The validity of the proposed observers and the controller has been investigated by using a Lyapunov＇s stability analysis strategy.

Design and engineering implementation of non-supplementary fired compressed air energy storage system: TICC-500

The integration and accommodation of the wind and solar energy pose great challenges on today’s power system operation due to the intermittent nature and volatility of the wind and solar resources.High efficient large-scale electrical energy storage is one of the most effective and economical solutions to those problems.After the comprehensive review of the existing storage technologies,this paper proposes an overall design scheme for the Non-supplementary Fired Compressed Air Energy Storage(NFCAES)system,including system design,modeling and efficiency assessment,as well as protection and control.Especially,the design principles of the multistage regenerative,i.e.heat recovery system which is used to fully recycle and utilize the waste heat from compression are provided,so as the overall system efficiency evaluation method.This paper theoretically ascertains the storage decoupling rules in the potential and internal energy of molecular compressed air and reveals the conversion mechanism of gas,heat,power,electricity and other forms of energy.On this basis,a 500-k W physical simulation system of CAES system(TICC-500,Tsinghua-IPCCAS-CEPRI-CAES)is built,which passed a system-wide 420-k W load power generation test with less pollution and zero carbon emissions.Besides,the multi-form energy conversion of multi-stage regenerative CAES and storage efficiency is verified,especially its incomparable superiority in solving the uncertainty problem in wind and solar power generation.Finally,the propaganda and application scenario of the CAES system in China is introduced.