共查询到20条相似文献,搜索用时 140 毫秒
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为了更好地了解化学链燃烧过程中气固流动的特点以及反应特性,基于化学动力学理论和颗粒动理学理论,考虑高颗粒浓度下摩擦应力的影响,运用双流体模型,对燃料反应器内化学链燃烧过程进行数值模拟,得到了燃料反应器内流场特性以及温度场分布规律。模拟结果同时得到了反应器内颗粒所形成的内循环流动结构。 相似文献
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利用有限元分析软件ANSYS对某款中型柴油机锻钢活塞进行温度场模拟,并对活塞在热载荷下的整体变形、等效应力、环槽变形及销孔变形进行分析。分析结果显示:活塞整体温度场和变形量分布正常;喉口和环槽应力较高;环槽和销孔变形量合理,为柴油机锻钢活塞的研发提供理论参考。 相似文献
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柴油机孔式喷油嘴内空穴流动的模拟分析 总被引:5,自引:0,他引:5
利用混合多相流体模型加空穴模型的方法,模拟了柴油机孔式喷油嘴稳定喷射时嘴内的空穴流动现象,分析了空穴在喷油嘴内形成机理及其分布情况。基于这一模型进一步分析了喷射压力、背压和喷孔长径比、喷孔入口圆角比、非轴对称喷孔等几何结构参数对喷孔内空穴分布的影响。通过模拟计算可知,提高喷射压差和减小喷孔入口圆角半径都可以提高空穴强度,同时也发现提高喷孔长径比可以使空穴在喷孔出口截面上分布更为均匀。从燃油空穴雾化理论的角度出发,空穴强度的提高以及在出口截面上的均匀分布都有利于燃油的破碎雾化。 相似文献
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During precision forging processes, the elastic and thermal deformations always take place simultaneously on the forging dies, which will affect the dimension accuracy of the final forging components. According to the classic Lamé formulas and thermoelastic mechanics theories, the thermoelastic deformation of a combined die was investigated. Directly related to geometric parameters, material properties, external stresses, and temperature distribution, the expressions of die deformation and contact normal stresses were derived. A three-layer combined die with three different temperature distributions was studied as a specific example. The thermoelastic deformations of each layer, as well as the contact normal stresses between them, were both calculated by the derived expressions and by finite element simulation. There was good agreement between the calculated values and simulated results, which demonstrated the effectiveness and accuracy of the theoretical derivation. Based on this, the total deformation on the inner surface of the combined die and the contact stress between contact layers under non-uniform temperature distribution that would influence the practical die initial design were discussed further. 相似文献
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利用仿真软件GT-Suit构建了高压共轨燃油喷射系统的仿真模型,分析了不同长径比下的共轨管内的压力波动规律、平均压力波动规律、喷油压力波动规律,进而分析了对喷油率的影响.通过仿真数据对比,在共轨管长为310 mm、长径比为16时,可使喷油系统的稳定性最优. 相似文献
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In this paper, an adaptive control problem of the maximum thermal stress in a smart composite disk is analyzed. The disk consists of a transversely isotropic structural layer onto which piezoelectric sensor and actuator layers are bonded. It is considered that an unknown heating temperature distribution acts on the structural layer and a thermally induced voltage distribution is measured on the sensor layer. The unknown heating temperature distribution is inferred from the knowledge of the measured voltage distribution. Applied voltages to electrodes arranged on every actuator layer are determined by optimization so that the maximum thermal stress in the structural layer is minimized and stress constraints imposed on the piezoelectric layers are satisfied. Finally, the suppression ratio of the maximum thermal stress is discussed based on numerical results. 相似文献
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提出了汽轮机转子在高应力疲劳与高温蠕变变互作用下的损伤本构模型与寿命评估方法,以及用于汽轮机转子结构分析的基本方程与变分原理,利用“间置加载”型荷载谱的特点,提出两个基本假设,并根据初始循环应力应变场对损过程中的循环应力应变场进行了有效描述,可对汽轮机转子结构寿命进行评估。 相似文献
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《International Communications in Heat and Mass Transfer》2001,28(4):585-594
The gaseous flow in a circular microtube is studied by using of a finite-difference technique. The influences of gas compressibility, rarefaction effect and temperature difference between inlet gas and tube wall on the mass flow rate are comprehensively described. The numerical results indicate that rarefaction effect decreases friction factor and increases mass flow rate due to velocity slip at tube wall. Although inlet Mach number in a microtube is low, gaseous compressibility effect may be significant, because in such a flow problem the length-diameter ratio of tube is usually large so that flow Reynolds number may change much more along the flow path. 相似文献
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This article deals with a stress control problem of a composite circular disk consisting of a structural layer onto which piezoceramic layers are bonded. When a heating temperature distribution acts on the bottom free surface, the maximum thermal stress in the structural layer can be controlled by applying electric potentials to electrodes concentrically arranged on each piezoceramic layer. The applied electric potentials are determined by solving an optimization problem so that the maximum thermal stress in the structural layer is minimized subject to constraints on the stresses in the piezoceramic layers. Finally, numerical results are presented. 相似文献
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The stress paths in the transient thermoelastoplastic analysis are strongly dependent upon the history of temperature, whereas stresses in the thermoelastic analysis are determined uniquely by the distribution of temperature. This paper treats the effect of the history of temperature on the thermoelastoplastic solution of a thick-walled tube. The transient state of stresses in the tube when subjected to inner-surface heating in which the temperature has an exponential time history is discussed in detail, on the assumption that thermal and material properties depend on temperature. 相似文献