一种船用柴油发动机增压器支架的设计

介绍了某船用柴油发动机增压器支架的设计,在考虑到满足功能要求、材料选择、空间布置等关键的基础上最终确定了增压器支架的设计结构,并通过有限元计算优化和验证了增压器支架的结构设计。     

增压器支架裂纹分析及优化

随着涡轮增压器在发动机上的应用越来越普遍,增压器固定方式是否合理、可靠也成为增压器整体布置工作中重要的一环。增压器除涡端螺栓打紧固定外,为增加系统模态及热稳定性,需增加支架固定。增压器支架不同于一般机舱固定支架,除了承受机械载荷外还需承受热应力,增压器支架在应用过程中失效风险也更大,这就要求增压器支架在开发时更加关注材料选择及结构设计的合理性。本文通过研究某机型上增压器耐久试验过程中出现的裂纹情况,从冲压件设计及制造两方面分析失效的原因,并根据问题真因制定优化措施防止裂纹产生。     

直列8缸柴油机增压器的振动研究与优化设计

某直列8缸发动机在开发过程中出现增压器振动速度大的问题,为此利用Abaqus软件建立增压器仿真模型,并根据增压器振动的实测结果对模型进行修正。根据仿真结果,提出改进建议：加强整机固定,降低振动源振动;降低增压器支架高度,增大增压器底座刚度。对优化后的增压器进行振动测试,结果表明振动速度低于限值,满足设计要求。     

ZN310A4型增压器支承结构改进设计

通过对ZN310A4型增压器支架及螺柱裂断质量问题的调查、分析,找出结构上存在的问题。对涡轮出气壳、支架定位结构及相关零部件材料作了改进。试验及装机运行考核结果证明,新结构有效解决了该型增压器支架及螺柱裂断质量问题。     

船用增压器系统模态分析及优化

为提升船用增压器系统的可靠性,以零部件的固有模态属性为基础,利用Abaqus软件对现有某6缸中速柴油机的增压器及相关零部件模型进行仿真模态分析,并通过试验对仿真结果进行校验。结果表明:基于仿真的模态分析满足精度要求,增压器系统一阶模态频率为67.36 Hz,低于设计要求的90 Hz,且转速为1150～1300 r/min时,共振倾向明显。根据仿真模态分析结果提出相应的优化解决方案,通过优化增压器支架结构形式,增加整个增压器及相关零部件的支撑刚度。试验结果表明:增压器系统的一阶模态频率提高到90.8 Hz,避免增压器系统在发动机运行区间内发生共振,提升了柴油机整机的运行可靠性,优化方案满足设计要求。     

柴油机增压器与排气歧管结合面漏气改进措施

某研发阶段的四缸柴油机在台架试验过程中,增压器与排气歧管结合面经常发生漏气现象。经分析主要原因为增压器垫片设计存在缺陷以及增压器垫片、增压器螺柱与螺母材料选择不合适,无法满足增压器与排气歧管在高温恶劣环境下的密封条件,最终导致密封失效而发生漏气。因此,对增压器垫片设计及垫片、螺柱与螺母材料进行改进,最终解决了增压器与排气歧管法兰结合面漏气问题。     

放气阀门漏气量测试系统的研制

研究提出了涡轮增压器放气阀门漏气量的测试系统,并针对样机制定了测试方法,同时进行了测量,试验结果将为增压器的合理设计、增压器与发动机的最佳匹配提供理论依据。     

HP55混流式水冷增压器研制及在柴油机上的应用

混流技术能有效提高涡轮增压器的效率,本文介绍了HP55增压器混流涡轮的叶片成形和设计,以及该增压器在CYQD32系列柴油机上的应用。试验结果表明：HP55增压器匹配CYQD32系列柴油机性能指标优于原机国外增压器。     

380ZL柴油机增压器选配及优化

为一款处于设计阶段的三缸柴油机匹配合适的废气涡轮增压器并进行优化,以使发动机达到设计要求。使用AVL公司的boost软件计算出匹配所需增压器的参数,以此为依据选取宁波天力公司的JK48增压器与发动机匹配。但模拟结果未满足设计要求。因此,在原增压器基础上模拟调整压气机与涡轮机,模拟结果显示:发动机与调整后的增压器联合运行时能够满足设计要求。模拟调整压气机与涡轮机的方法可为增压器匹配工作提供快速、准确的指导。     

某型号增压器故障分析与改进

通过对某型号增压器失效质量问题的调查、分析,进行设计改进,解决了该增压器失效的质量问题。     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996