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发动机冷却系统流固耦合稳态传热三维数值仿真 总被引:9,自引:0,他引:9
为解决发动机传热计算时冷却水与缸套、机体之间的流动与传热耦合边界问题,建立了发动机活塞组-缸套-冷却水-机体三维流固耦合系统,并利用有限元分析软件的流固耦合计算功能,把单个零件的传热外边界条件处理成内边界,使得传热仿真更合理更简单。以某增压柴油机为例,用有限元分析软件ANSYS对建立的三维流固耦合模型进行了稳态传热数值仿真,得到了耦合系统的温度场和流场云图。与标定工况下活塞和缸套的温度场测量数据进行了对比分析,结果表明:仿真结果与实测数据吻合较好,误差控制在8%以内。由此说明应用流固耦合仿真方法可以较好地模拟发动机稳态传热。 相似文献
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流固耦合仿真技术在发动机稳态传热计算中的应用 总被引:3,自引:0,他引:3
为解决发动机传热研究中冷却水与缸套、机体之间的流动与传热问题,将有限元软件中提供的流固耦合仿真技术应用到发动机稳态传热计算中。建立了发动机活塞组-缸套-冷却水-机体流固耦合传热模型,该模型既包括了固体与固体之间的接触传热,也包括了流体与固体之间的耦合传热。同时,零件之间的传热边界条件也变得既简单又合理。以某型号柴油机为例进行了有限元仿真计算,并与活塞和缸套的温度场测量数据进行了对比分析。结果表明:仿真结果与试验测量数据误差较小,应用流固耦合仿真方法可以较好的模拟发动机稳态传热状态。 相似文献
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利用FLUENT分析软件对发动机的稳态传热进行了仿真模拟。以所建立的某柴油机耦合传热系统为例进行了仿真计算,得到了耦合系统(活塞、缸套、冷却水套)的温度场等相关信息。计算结果表明,用耦合法模拟柴油机活塞组、缸套和冷却水之间的稳态传热是可行的。 相似文献
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流固耦合研究纳米流体在内燃机冷却水腔中的传热 总被引:1,自引:0,他引:1
在发动机的冷却系统内用纳米流体代替传统的冷却工质水,对六缸柴油机采用整体耦合的方法,将冷却系统与内燃机固体部件当作一个耦合体,使流固边界成为内部实时边界,对纳米流体在整机冷却系统中的流动与传热特性进行研究,考察不同种类、不同体积分数、不同粒径的纳米流体对内燃机冷却系统传热的影响规律,给出了整机冷却水套内冷却液的流场、换热系数、压力场以及准确的温度场分布,为内燃机热应力的计算以及纳米流体在柴油机冷却水腔的应用奠定了理论基础. 相似文献
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通过车用天然气发动机,建立了包括冷却水腔内流动沸腾传热、气缸盖内固体导热及缸内进排气燃烧在内的多场耦合仿真系统.采用直接耦合算法进行气缸盖固体区域与冷却水腔流体区域流固耦合仿真,采用顺序映射的方式进行缸内燃气区域与流固区域多场耦合仿真.通过CFD软件中UDF功能嵌入合适的单相沸腾传热模型对缸盖水腔内传热进行分析计算,并在此基础上结合试验测量结果,对比分析发动机在不同冷却水温度与不同冷却系统压力下缸盖温度场变化趋势.研究表明:多场耦合仿真系统可以解决缸盖传热边界不易给定的难题,能够更真实准确地描述出缸盖复杂传热过程,且考虑沸腾传热因素后有助于提高在不同冷却条件下缸盖热关键区域温度场的计算精度. 相似文献
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High efficient configuration design and simulation of platelet heat exchanger in solar thermal thruster 总被引:1,自引:0,他引:1
Solar thermal propulsion system includes solar thermal propulsion and nuclear thermal propulsion, and it is a sig- nificant issue to improve the heat transfer efficiency of the solar thermal thruster. This paper proposes a platelet configuration to be used in the heat exchanger core, which is the most important component of solar thermal sys- tem. The platelet passage can enhance the heat transfer between the propellant and the hot core heated by the concentrated sunlight. Based on fluid-solid coupled heat transfer, the paper utilized the platelet heat transfer characteristic to simulate the heat transfer and flow field of the platelet passage. A coupled system includes the coupled flow and heat transfer between the fluid region and solid region. The simulation result shows that the propellant can be heated to the design temperature of 2300K in platelet passage of the thermal propulsion system, and the fluid-solid coupled method can solve the heat transfer in the platelet structure more precisely. 相似文献
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Thermal-fluid-solid coupling of electric heat storage device based on wind power absorption 下载免费PDF全文
电网调峰能力不足,弃风问题严重,已成为我国风力发电规模进一步扩大的瓶颈。通过配置蓄热装置参与风电调峰,改变传统“以热定电”的约束模式,是解决我国大量弃风问题的一个趋势。提高电热蓄能装置效率及优化蓄热装置分布对于实现有效调峰具有重要意义。本文针对固体电蓄热装置内流动、传热、应力等现象,建立了热-流-固多场三维耦合传热数学模型,采用流-固耦合传热模型将难以确定的热流边界转化为系统内部边界,分析固体电蓄热装置温度场及应力场分布,并对比三种不同孔隙率、电热丝排布方式对蓄热装置温度分布均匀性及热膨胀量的影响。研究结果对提高固体电蓄热装置的效率以及电网调峰具有一定的参考价值。 相似文献
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Cooling technology of gas turbine blades,primarily ensured via internal forced convection,is aimed towards withdrawing thermal energy from the airfoil.To promote heat exchange,the walls of internal cooling passages are lined with repeated geometrical flow disturbance elements and surface non-uniformities.Raising the heat transfer at the expense of increased pressure loss;the goal is to obtain the highest possible cooling effectiveness at the lowest possible pressure drop penalty.The cooling channel heat transfer problem involves convection in the fluid domain and conduction in the solid.This coupled behavior is known as conjugate heat transfer.This experimental study models the effects of conduction coupling on convective heat transfer by applying iso-heat-flux boundary condition at the external side of a scaled serpentine passage.Investigations involve local temperature measurements performed by Infrared Thermography over flat and ribbed slab configurations.Nusselt number distributions along the wetted surface are obtained by means of heat flux distributions,computed from an energy balance within the metal domain.For the flat plate experiments,the effect of conjugate boundary condition on heat transfer is estimated to be in the order of 3%.In the ribbed channel case,the normalized Nusselt number distributions are compared with the basic flow features.Contrasting the findings with other conjugate and convective iso-heat-flux literature,a high degree of overall correlation is evident. 相似文献
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考虑沸腾换热的内燃机流固耦合传热分析 总被引:1,自引:0,他引:1
某发动机在开发过程中缸套顶部出现机油结焦现象.为分析原因,建立了该发动机缸盖缸体整机耦合传热模型,通过CFD三维仿真获得冷却水侧及缸内燃气侧的温度和对流换热系数分布,并映射至对应结构分析边界单元,建立了整机结构传热分析的边界条件;同时基于BDL单相流沸腾换热模型编写相关子程序考虑了沸腾换热的影响,求解分析了该发动机试验状态下的温度场,并进行了优化.计算表明,结焦现象发生区域温度明显高于机油碳化温度,同时沸腾换热对局部关键高热区影响可达15℃以上.为验证分析结果,分别测量了原方案和优化方案缸套顶部缸间温度,结果表明,考虑沸腾换热后缸间温度计算值与实测数据非常接近,采用优化方案后缸套顶部机油结焦问题得到排除. 相似文献
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The phenomenon of temperature gradient bifurcation in a porous medium is analyzed by studying the convective heat transfer process within a channel filled with a porous medium, with internal heat generation. A local thermal non-equilibrium (LTNE) model is used to represent the energy transport within the porous medium. Exact solutions are derived for both the fluid and solid temperature distributions for two primary approaches (Models A and B) for the constant wall heat flux boundary condition. The Nusselt number for the fluid at the channel wall is also obtained. The effects of the pertinent parameters such as fluid and solid internal heat generations, Biot number and fluid to solid thermal conductivity ratio are discussed. It is shown that the internal heat generation in the solid phase is significant for the heat transfer characteristics. The validity of the one equation model is investigated by comparing the Nusselt number obtained from the LTNE model with that from the local thermal equilibrium (LTE) model. The results demonstrate the importance of utilizing the LTNE model in the present study. The phenomenon of temperature gradient bifurcation for the fluid and solid phases at the wall for Model A is established and demonstrated. In addition, the temperature distributions for Models A and B are compared. A numerical study for the constant temperature boundary condition was also carried out. It was established that the phenomenon of temperature gradient bifurcation for the fluid and solid phases for the constant temperature boundary condition can occur over a given axial region. 相似文献
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采用共轭传热计算方法,对某柴油发动机废气涡轮增压器径流涡轮流场进行了数值模拟,对比了叶轮在绝热和传热条件下温度分布的差别,研究了传热边界对叶轮温度分布的影响。结果表明,绝热条件下,叶片两侧的温度存在显著的温差,并且从叶轮进口到出口也有明显的温降;而传热条件下,相同叶高下的叶片表面温度分布近乎于一条直线,压力面和吸力面的温度几乎相同;在热平衡条件下,叶轮实体内的温度范围很小,不超过10 K,温度梯度较小表明由温差引起的热应力很小。 相似文献