防漏降噪的齿轮室罩盖的设计

柴油机齿轮室罩盖即影响发动机外观又影响发动机性能－三漏和噪声。笔者介绍具备上述要求的齿轮室罩盖的设计。新设计齿轮室罩盖经台架试验,已达到设计预期要求。     

基于拓扑优化和形状优化的低噪声齿轮室罩盖设计

为了降低发动机齿轮室罩盖的噪声辐射,进行了齿轮室罩盖的噪声频谱分析和模态分析,确定了齿轮室罩盖噪声主要频率区域,使用HyperWorks/Optistruct软件,采用拓扑优化和形状优化的方法,对第5阶移频和重量最小为目标进行了优化设计.优化后的齿轮室罩盖重量减轻了0.46 kg,第5阶模态频率被移出了危险区域,其余各阶模态频率均得到了提高.声学模拟计算结果表明:在1 600～1 700 Hz频率区域内,优化后的齿轮室辐射噪声得到明显降低.     

气门室罩盖高温烧蚀的仿真分析及改进

为解决增压直喷发动机功率高密度、高排温带来的气门室罩盖烧结融化的问题,采用仿真分析排气系统对气门室罩盖的温度影响,设计多种方案解决气门室罩盖烧结问题,最终通过试验验证并解决问题。结果表明,采用仿真手段对温度场进行风险规避可以提前规避问题,节省时间,快速解决问题。     

结合多种方法进行六缸柴油机噪声源识别研究

针对六缸柴油机进行了噪声源识别和降噪研究工作.通过单缸熄火法进行燃烧噪声和机械噪声的分离,以及表面振动法和声学照相法,结合振动和噪声信号的频谱分析法,对发动机表面辐射噪声进行了识别;针对表面噪声辐射的主要噪声源采取了屏蔽措施.研究结果表明:六缸柴油机的主要噪声源为机械噪声,通过对齿轮室罩盖、气缸盖罩盖、充电电机外壳和喷油泵等薄壁件采取屏蔽措施,或者进行结构优化,能有效降低整机噪声.     

基于有限元法的发动机曲轴定时齿轮的优化设计

基于有限元分析方法,在静态分析基础之上,以发动机曲轴定时齿轮的厚度为设计的变量,以发动机曲轴定时齿轮的质量作为目标函数,建立发动机曲轴定时齿轮的优化模型。采用ANSYS对发动机曲轴定时齿轮进行有限元的结构分析和优化．从而优化发动机曲轴与凸轮轴之间的传动。     

高性能轻型国V柴油机的开发

介绍1款高性能轻型国V小排量柴油机的重点开发技术。通过燃烧开发和VGT增压器、喷油器等硬件选型试验来实现发动机的性能和排放开发目标。采用一种加热性能好的低压金属预热塞,并与油束最佳匹配,显著提高发动机低温冷起动能力。EGR技术是满足轻型国V以上排放发动机的一种很重要的技术,该发动机开发了EGR冷却器防堵塞的主要技术措施。开发了适应双质量飞轮的前端附件轮系。通过开发新减振器、降低传动齿轮和增压器噪声、优化正时罩盖等技术措施来进一步降低发动机的噪声。     

SC9D型柴油机降噪措施的研究与应用

一款SC9D型柴油机配套应用于轮式装载机,整车测试噪声未能达到GB 16710第二阶段限值的要求。为协助装载机厂家降低整车噪声,分别从柴油机喷油提前角、有效输出功率、齿轮室罩盖、曲轴减振器、冷却风扇及速比等6个方面对柴油机噪声进行了研究。研究结果表明,采用经过降噪设计的柴油机的装载机整车噪声由114.9 d B(A)降低至112.7 d B(A),满足了噪声标准的要求。     

某大功率柴油机噪声异常的分析与优化

针对某新研发的大功率柴油机怠速状态后端噪声大,并伴有异响的问题,通过台架和整车发动机振动噪声试验确定:齿轮室、空压机和高压油泵是发动机后端噪声的主要噪声源,其中齿轮室的噪声是发动机异响的主要噪声源。据此提出了两种降噪方案:一,在齿轮室、高压油泵和空压机等处加装遮蔽罩;二,改进齿轮系设计。试验结果显示:降噪效果明显。     

内燃机表面辐射噪声控制探讨

通过对内燃机表面辐射噪声测试试验的分析研究,对主要表面辐射噪声的发生部件如油底壳、气门罩盖、齿轮、空滤器、消声器提出改进措施,以降低噪声.     

引进国外发动机齿轮国产化设计问题探讨

引进国外发动机齿轮,在国产化设计时,经常遇到引进图纸与我国的齿轮设计方法相矛盾的情况,此时应根据实际情况认真分析.     

SHN0_7_0_4_95型水管式热水锅炉的设计

本文介绍新型水管式热水锅炉的设计经验,目前该型锅炉已广泛推广应用。     

发动机非点火热平衡试验台架测试系统开发

介绍了非点火发动机台架台架选择和搭建、测试系统的硬件和软件设计方案。通过非点火发动机冷却系统热平衡试验,证明了该台架系统能够满足发动机子系统试验所需的功能。     

Data integration/exchange - Part 1: existing technical and business opportunities

The deregulation of the electric utility industry combined with development of advanced technology has raised many questions as how to make the power system operation more cost effective while preserving a high level of reliability and security. The utilities are developing different strategies for achieving this goal, enabling them to stay competitive. Many other new businesses are being formed to take advantage of the new opportunities in the marketplace.This article provides an overview of the possible new technical and business opportunities and benefits in developing advanced strategies for data integration and information exchange. It describes the efforts to discover new approaches to formulating a successful business strategy that would ensure competitiveness, with particular focus on the role of data integration and information exchange in developing new technical and business opportunities in the deregulated market place. In order to put the above discussion into better perspective, two new applications, namely a comprehensive fault and disturbance analysis and a novel two-stage state estimation, are presented as illustrative examples of how additional benefits can be obtained through assigning new business value to information and data.     

Extended combustion model for single boron particles - Part II: Validation

Boron particle addition to propellants is advantageous due to a very high heating value. However, the combustion of boron particles is a very complex process because of an inhibiting oxide layer covering the particles. This layer has to be removed before vigorous combustion can start. Hence, the boron particle combustion process runs in two distinct stages. There are two outstanding combustion models for single boron particles in the literature. A very detailed model by the Princeton/Aerodyne-group features hundreds of elementary reactions and considers all physical processes in the particle environment. The second model developed at Penn State University takes on a global approach with only a few reactions which makes it promising for CFD applications. A careful analysis of this model revealed some inconsistencies, errors and drawbacks which gave rise to the new model presented in Part I of this paper. The new model comprises a consistent formulation of the heat and mass transfer processes in the particle environment based on a quasi-steady approach, accounts for boron evaporation which is a relevant process despite the high boiling point of boron, and it considers the influence of forced convection on the particle conversion. The chemical reaction rates adopted from the original model were revised and are slightly changed, the differential equations to be solved are corrected and an iterative solution algorithm was introduced. In Part II, the results of the new extended model are compared to experimental data from literature and opposed to results of the other two models. They show reasonable agreement with measured data. A more complex transient model is also derived which serves as a means of scrutinising the principal assumption of the new model which are quasi-steady state changes. It appears that the new model is suitable for boron particle sizes relevant for ramjet combustion chambers.     

空气源热泵新风机组节能防冻研究

本文讨论了寒冷地区新风机组冬季被冻坏的原因及传统解决方法的问题,提出了空气热泵新风机组节能防冻新方法,即利用热泵冷凝器回收排风废热以加热引入室内新风。新系统的运行经验表明,各种温度随时间的变化趋于稳定,热泵的平均COP=3．7—4．6,节约电能达52％～84％,解决了防冻问题并改善了室内空气质量。     

Solar PV lanterns with centralized charging system - a new concept for rural lighting in the developing nations

A new concept has been introduced for providing electric light to rural households through portable solar PV lanterns, charged regularly in a centralized charging shop located in the village and operated on a commercial basis by an entrepreneur. The technical feasibility of a charging shop for charging solar PV lanterns has been described in detail. The results of an actual field trial of the proposed system are also reported. Finally, the economic viability of the system is described.     

Comparative evaluation of LNG - based cogeneration systems using advanced exergetic analysis

During the last two decades the total cost of LNG technology has decreased significantly due to improvements of the liquefaction process. However, the regasification system has not been considerably improved. It is known that for the regasification process about 1.5% of LNG is used. Two novel, gas-turbine-based concepts for combining LNG regasification with the generation of electricity are discussed in this paper. These concepts have relatively low investment costs and high efficiencies. An advanced exergetic analysis is applied to one of these attractive LNG-based cogeneration systems to identify the potential for improvement and the interactions among components. In an advanced exergetic analysis, the exergy destruction within each component is split into unavoidable/avoidable and endogenous/exogenous parts. The advantages of this analysis over a conventional one are demonstrated. Some new developments in the advanced exergetic analysis and options for improving the concepts are also presented.     

ZGLJO．1－160－2．5真空感应熔炼炉液压系统

介绍新研制的立式真空感应熔炼炉的液压系统。阐述该系统工作原理、程序、结构及特点。     

WGL-6微机故障录波分析装置设计方案

电力系统的发展对变电站故障录波装置提出了更高的要求，计算机软硬件技术的飞速进步为微机型故障录波装置的性能改善提供了必要条件。介绍了新型WGL-6型微机故障录波分析装置技术特点、硬件结构配置、性能以及软件包的组成及其功能，还介绍了故障录波的全过程、这种录波方式的特点和这种录波器与旧型录波器相比较而添加的特有功能。