热管中冷器与前端冷却模块的匹配优化研究

为解决大功率柴油机铝中冷器在高温下强度下降的问题,针对某型载重车冷却模块,在风洞性能试验台架上对其进行了研究,引入热管中冷器解决目前铝中冷器在超高温下的适用性问题,并对铝中冷器做了2种优化改进方案。试验结果显示:热管中冷器可以很好地降低铝中冷器的进口温度,同时优化后的中冷器也能很好地满足中冷要求。在此基础上,水箱散热性能可提升3.36%～13.08%,冷却模块在满足原发动机的散热要求下可以做得更紧凑。     

气—气中冷器试验台的研制

内燃机采用增压中冷技术,由于可以大幅度地提高功率,改善发动机热负荷,降低燃油消耗率和排气污染,因而被广泛采用。根据粗略统计,目前在增压柴油机中,采用中冷技术的已占增压机型的70％以上,并且大有发展趋势。特别是在车用增压中冷发动机中,作为增压系统中重要部件的中冷器,对其进行深层次地换热机理的研究,优化结     

基于CFD的中冷器气室结构优化设计

为了提高汽车中冷器的工作性能及效率,基于计算流体动力学(computational fluid dynamics,CFD)方法,针对芯体相同、气室结构不同的2种中冷器内部气体流场进行三维仿真分析,研究气室结构差异对中冷器工作性能及效率的影响。仿真计算和对比分析表明,中冷器气室是整个中冷器压力损失的重要部件,内部气体流动情况对其散热性能有直接影响。仿真结果表明:由于100-3型中冷器气室具有侧壁倾角,气体流动过程中压降较小,出口速度较100-2型高,整体流动性能较100-2型中冷器好。     

浅谈内燃机增压中冷技术

随着国民经济及国防工业的迅速发展,内燃机动力性、经济性及排放等各项指标日臻完善。增压度的不断提高,尤其增压中冷已成为重要手段。同样,车用发动机增压中冷技术愈来愈受到人们的青睐。本文综合了国内外增压中冷技术的发展现状,分析了中冷器冷却元件的结构和工艺的进步,并提出了一些建设性的见解,以供决策参考。     

一种新型车用柴油机中冷器的热力计算方法及分析

针对某新型平行流式内燃机“空一空”式中冷器进行了热力计算和分析。建立了该型中冷器计算模型,采用稳态分布参数方法研究了中冷器的散热能力和空气侧的阻力特性。计算结果和试验值的对比,阻力值的偏差不超过5％,换热率的偏差在10％以内,说明此计算方法可以满足平行流式中冷器的设计使用。     

机车柴油机行驶风中冷器初探

探讨利用列车行驶风直接冷却增压空气的空-空冷却器——行驶风中冷器,其性能远优于水冷中冷器;提出应将出气温度作为评价中冷器性能的另一关键性指标。     

增压器和中冷器联合性能试验台

增压器和中冷器是柴油机增压系统的重要部件 ,其性能的优劣直接影响柴油机的经济性、动力性及可靠性。目前 ,我国机务部门已经实现了增压器的集中修理 ,并有完备的性能试验设备 ,但对中冷器的性能试验还缺乏必要的设备 ,这使装车运用的中冷器质量难以得到保证。为此 ,提出了建造增压器、中冷器联合试验台方案 ,它具有投资少 ,试验费用低 ,维修保养方便等优点。     

卡特3306中冷器与6135增压柴油机的匹配试验与研究

通过分析617中冷器和卡特3306中冷器的结构特点,提出了用卡特3306中冷器替代原617中冷器来改善6135增压中冷柴油机的整机性能。试验结果表明,卡特3306中冷器在6135增压柴油机上配置合理,柴油机整机性能得到改善,用卡特3306中冷器匹配的6135增压中冷柴油机不仅可作为船用机型,且为其它用途的柴油机机型的发展也提供了较好前景。     

热管技术在内燃机上的应用

热管是一个封闭的高效传热器,它是利用工质蒸发吸热,冷凝放热的原理进行工作的。热管用在车用发动机上,可以提高燃油和机油利用率,减少环境污染,控制冷却水温,提高发动机寿命;还可采用热管技术利用大型内燃机的余热取暖等。     

热管技术在内燃机上的应用

热管是一个封闭的高效传热器,它是利用工质蒸发吸热,冷凝放热的原理进行工作的。热管用在车用发动机上,可以提高燃油和机油利用率,减少环境污染,控制冷却水温,提高发动机寿命;还可采用热管技术利用大型内燃机的余热取暖等。     

燃烧室部件耦合系统过渡工况传热全仿真模拟研究

内燃机的起动、停车、加载等运行工况发生急剧变化（过渡工况）过程中,其燃烧室部位外于强烈地被加热或被冷却状态。这种热冲击增加了部件的动态疲劳热应力,给内燃机的可靠性带来严重恶果,是导致燃烧室部位破裂的主要原因之一。燃烧室部件的传热研究是热负荷计算和评定的基础,对内燃机的可靠性设计具有重要意义。作对燃烧室部件活塞组气缸套耦合系统在过渡工况下的耦合传热关系进行了较深入的研究,建立了描述这一传热过程的数学模型;并利用该模型,模拟了125风冷柴油机在各种过渡工况下的传热情况。     

The efficiency of heat transfer through the ash deposits on the heat exchange surfaces by burning coal and coal-water fuels

The results of the numerical simulation of heat transfer from the combustion products of coal and coal-water fuels (CWF) to the internal environment. The mathematical simulation has been carried out on the sample of the pipe surfaces of the combustion chamber of the boiler unit. The change in the characteristics of heat transfer (change of thermochemical characteristics) in the conditions of formation of the ash deposits have been taken into account. According to the results of the numerical simulation, the comparative analysis of the efficiency of heat transfer has been carried out from the furnace environment to the inside pipe coolant (water, air, or water vapor) from the combustion of coal and coal-water fuels. It has been established that, in the initial period of the boiler unit operation during coal fuel combustion the efficiency of heat transfer from the combustion products of the internal environment is higher than when using CWF. The efficiency of heat transfer in CWF combustion conditions is more at large times (t ≥ 1.5 h) of the boiler unit. According to the results the numerical simulation of the temperature distributions in the system “pipeline environment — pipe wall — a layer of ash — the products of combustion” have been obtained. A significant decrease in heat flux from the combustion products to the inside pipe coolant in the case of coal combustion compared to CWF has been found. It has been proved that this is due primarily to the fact that massive and strong ash deposits are formed during coal combustion.     

Numerical study of heat transfer of hydrogen combustion in noble gases atmosphere in compression ignition engine

The high energy content of hydrogen and zero carbon emission from hydrogen combustion is very important for compression ignition engine development. Hydrogen requires a very high auto-ignition temperature, which encourages replacing nitrogen with noble gases with higher specific heat ratio during compression process. In noble gases-hydrogen combustion, higher combustion temperature potentially leading to a higher heat loss. This paper aims to investigate the effect of hydrogen combustion in various noble gases on heat distribution and heat transfer on the cylinder wall. Converge CFD software was used to simulate a Yanmar NF19SK direct injection compression ignition engine. The local heat flux was measured at different locations of cylinder wall and piston head. The heat transfer of hydrogen combustion in various noble gases at different intake temperatures was studied using the numerical approach. As a result, hydrogen combustion in light noble gases such as helium produces faster combustion progress and higher heat temperature. The hydrogen combustion that experienced detonation, which happened in neon at 340 K and argon at 380 K, recorded a very high local heat flux at the cylinder head and piston due to the rapid combustion, which should be avoided in the engine operation. At a higher intake temperature, the rate of heat transfer on the cylinder wall is increased. In conclusion, helium was found as the best working gas for controlling combustion and heat transfer. Overall, the heat transfer data gained in this paper can be used to construct the future engine hydrogen in noble gases.     

内燃机缸内零件系统传热的计算机模拟进展

本文综合介绍了内燃机缸内零件系统传热计算机模拟的国际和国内现状，并介绍了作者目前正在进行的缸内耦合三维零件系统传热的研究情况。由于缸内零件传热的计算机模拟是未来内燃机虚拟设计的关键技术，因而有必要对缸内零件的分析历史和现状进行综合探讨。     

内燃机传热全仿真模拟研究进展综述

概述了内燃机传热研究的意义和发展;对内燃机传热研究的新领域－缸内气体的流动、燃烧、对流传热、辐射传热等模型与燃烧室部件整体导热模型耦合的计算机模拟,进行了全面综述,并指出了下一步应着重解决的问题。     

Analysis of local convective heat transfer in a spark ignition engine

A computational fluid dynamics (CFD) code is applied to simulate fluid flow, heat transfer and combustion in a four-stroke single cylinder engine with pent roof combustion chamber geometry, having two inlet valves and two exhaust valves. Heat flux and heat transfer coefficient on the cylinder head, cylinder wall, piston, intake and exhaust valves are determined with respect to crank angle position. Results for a certain condition are compared for total heat transfer coefficient of the cylinder engine with available correlation proposed by experimental measurement in the literature and close agreement are observed. It was found that the local value of heat transfer coefficient varies considerably in different parts of the cylinder, but they have equivalent trend with crank angle. Based on the results, new correlations are suggested to predict maximum and minimum convective heat transfer coefficient in the combustion chamber of a SI engine.     

二甲醚均质压燃发动机燃烧特性的研究

二甲醚均质压燃发动机由一台单缸柴油机改造而成,其压缩比为10．7。二甲醚气体随进气进入气缸,形成均质混合气。通过试验采集分析缸内压力,结果表明二甲醚均质压燃燃烧是一个两阶段放热过程,分别发生在610K和900K左右。第一阶段放热量较少,约占10％,正常情况下第二阶段集中在上止点附近,释放出70％以上的燃料热量。发动机负荷对最大缸压力及其出现位置、压力升高率和放热率曲线形状等都有重要影响,而发动机转速对它们的影响比较小。     

Stirling 发动机燃烧及换热分析

基于碳氢燃料燃烧化学平衡反应计算,得到燃烧产物温度及组分成份,在此基础上计算燃气物性,从而计算了热气机外燃系统加热管的对流换热系数、辐射换热系数及后排换热管的肋片换热,对燃用空气和液氧两种燃烧情形进行了对比计算,并计算了各种因素对燃烧的影响,对计算结果进行了分析和讨论,得到了很有价值的结论,为热气机外燃系统结构设计提供了借鉴。