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液力变矩器作为一种有效的增矩变速元件广泛应用于车辆传动中。通过对某液力变矩器整周模型简化、网格划分,利用CFD(Computational Fluid Dynamics)技术对其进行流体计算,获取了液力变矩器内流场的速度及压力信息,得出全充液状态下的转速比i、变矩比K、泵轮转矩系数λ以及效率η,从而得到液力变矩器的原始特性曲线。对样机的台架试验结果与一维束流理论计算结果进行了对比分析,对仿真结果进行了验证,结果表明,三者在数值上吻合较好,说明三维流场数值计算方法应用于液力变矩器的性能预测是可行的,可以应用于工程实际。 相似文献
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液力变矩器的流场数值模拟及试验对比 总被引:1,自引:0,他引:1
液力变矩器作为一种有效的增矩变速元件广泛应用于车辆传动中。通过对某液力变矩器整周模型简化、网格划分,利用CFD(Computational Fluid Dynamics)技术对其进行流体计算,获取了液力变矩器内流场的速度及压力信息,得出全充液状态下的转速比i、变矩比K、泵轮转矩系数λ以及效率η,从而得到液力变矩器的原始特性曲线。对样机的台架试验结果与一维束流理论计算结果进行了对比分析,对仿真结果进行了验证,结果表明,三者在数值上吻合较好,说明三维流场数值计算方法应用于液力变矩器的性能预测是可行的,可以应用于工程实际。 相似文献
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1 前言 液力变矩器早期研制是凭经验,采用多种模型及试验筛选改进,最后定型。随着技术的发展、理论的建立,要求应用计算方法进行设计,使制出的产品试验性能与计算性能相一致。由于束流理论的一些假定与实际流动状况差别很大,一些损失按固定流道方法计算与旋转流道内流动不相符,加之参数众多,使计算变得困难、复杂,且实际试验性能与计算差别很大。因此,一般以计算作为初算,第一轮试制后再根据试验性能以一般理论为指导修改设计,几经修改才能定型。我所研制开发的TY220型液力变矩器,采用理论计算与试验相结合的方法,在研究液力变矩器工作轮几何参数对性能影响,尤其是在改变泵轮、涡轮叶栅的进出口角度差值,对提高液力变矩器性能参数的研究取得了进展。本文较详细地介绍了这种改善和提高液力变矩器性能参数的原理、方法和结果。 相似文献
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双泵轮液力变矩器设计与特性计算中的若干问题研究 总被引:1,自引:0,他引:1
本文探讨了双泵轮液力变矩器设计计算中的若干问题,介绍了其在装载机上应用时,其有效直径的确定方法;用单泵轮液力变矩器改制双泵轮液力变矩器时,泵轮切割部位的计算方法及双泵轮液力变矩器原始特性和能容调节特性的计算方法。 相似文献
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用激光多普勒流速计测量液力变矩器流场的速度分布 总被引:2,自引:0,他引:2
本文叙述了用激光多普勒流速计对YB-355型液力变矩器泵轮和涡轮内流场速度分布进行测量的装置、方法、步骤以及试验的结果。 相似文献
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液力变矩器叶栅系统设计软件采用模块式结构,简单易行,摒弃了原有手工设计的不足,提高了变矩器的开发速度及精度,有利于选择最佳方案,保证设计一次性成功.利用所开发的设计软件进行新品设计及对现有液力变矩器叶栅系统几何参数进行验算,特性计算结果与样机的性能试验结果进行对照.基本满足设计要求.为今后新品开发搭建了平台. 相似文献
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液力变矩器中涡空化的产生和发展严重影响其内流场及外特性,尤其在极端工况下。精细识别液力变矩器内流场非定常多尺度三维涡结构和提取涡空化空间结构特征是目前研究的热点问题。基于计算流体动力学,采用应力混合涡模型对液力变矩器空化流场进行高精度数值模拟,基于第二代和第三代涡识别技术选取Q准则和Ω方法,两种典型的涡识别方法对液力变矩器流道内部空化涡结构进行三维重构,分析低速比工况下各叶片表面空化特征动态演化规律并重点研究导轮叶片处空化现象。研究结果表明:Q准则阈值选择盲目性大,难以同时识别到空化流场中的强涡与弱涡结构;Ω方法能够在较大阈值范围内精确地辨识空化流场涡结构;制动工况下导轮内空化现象最为严重。 相似文献
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大能容高宽效可调变矩器设计试验研究 总被引:2,自引:0,他引:2
在动力机转速不调节的工程机械上,以及其它需要调速的各种工作机械上,导轮叶片转动的可调变矩器日益得到采用,YBT560型可调变矩器采用了前倾叶片泵轮,大的流量系数,合理进行了叶栅设计,获得大能容,效率高,高效区宽等较佳的性能,比现在广泛应用的LB46型可调变矩优越。 相似文献
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A computational fluid dynamics (CFD) model that evaluates mechanical mixing in a full-scale anaerobic digester was developed to investigate the influence of sewage sludge rheology on the steady-state digester performance. Mechanical mixing is provided through an impeller located in a draft tube. Use is made of the Multiple Reference Frame model to incorporate the rotating impeller. The non-Newtonian sludge is modeled using the Hershel–Bulkley law because of the yield stress present in the fluid. Water is also used as modeling fluid to illustrate the significant non-Newtonian effects of sewage sludge on mixing patterns. The variation of the sewage sludge rheology as a result of the digestion process is considered to determine its influence on both the required impeller torque and digester mixing patterns. It was found that when modeling the fluid with the Hershel–Bulkley law, the high slope of the sewage stress-strain curve at high shear rates causes significant viscous torque on the impeller surface. Although the overall fluid shear stress property is reduced during digestion, this slope is increased with sludge age, causing an increase in impeller torque for digested sludge due to the high strain rates caused by the pumping impeller. Consideration should be given to using the Bingham law to deal with high strain rates. The overall mixing flow patterns of the digested sludge do however improve slightly. 相似文献
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分析推土机用液力机械变矩器轴承支承结构的特点,根据液力机械变矩器叶轮轴向力的单向性特征,轴承支承结构型式布置成左边游动支承加右边单向固定支承的结构型式.SD8型的轴承支承结构右边采用单列圆锥滚子轴承,单列圆锥滚子轴承的轴向游隙在安装时,靠控制旋转总体右端面与限位调整隔环的间隙来调整,间隙小降低最高效率,间隙大减小轴承使用寿命,最佳间隙应该是液力机械变矩器的最高效率和单列圆锥滚子轴承的最长使用寿命这两要素最优组合的平衡点.最佳间隙不是装配出来的,而是磨合出来的.根据总装、出厂试验和性能试验的经验,总结出单列圆锥滚子轴承轴向游隙的调整方法. 相似文献
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With the aim of probing for design theory of cutterhead excavation system of earth pressure balance (EPB) machine, the parameters representing the system performance are concluded firstly. Then a 3D model for cutterhead excavation system of EPB machine is presented with the discrete element method (DEM) software PFC3D, which is capable of simulating the tunneling ground in site, the machine structure and the excavation operation. The performance parameters indicating stability of excavation face, soil discharging rate, cutterhead system torque and cutter wear are measured by running the DEM code. The results obtained with the DEM model are accord with situ data. It indicates that the DEM model is a promising method replacing the field experiment to analyze the influences of the structural parameters on system performances, which are essential for structure optimization design of the cutterhead system of EPB machine. 相似文献
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Nobuyuki Fujisawa 《Journal of Wind Engineering & Industrial Aerodynamics》1992,40(3):277-292
The aerodynamic performance and the flow fields of Savonius rotors at various overlap ratios have been investigated by measuring the pressure distributions on the blades and by visualizing the flow fields in and around the rotors with and without rotation. Experiments have been performed on four rotors having two semicircular blades but with different overlap ratios ranging 0 to 0.5. The static torque performance is improved by increasing the overlap ratio especially on the returning blade, which is due to the pressure recovery effect by the flow through the overlap. On the other hand, the torque and the power performance of the rotating rotor reaches a maximum at an overlap ratio of 0.15. This effect is largely created by the Coanda-like flow on the convex side of the advancing blade, which is strengthened by the flow through the overlap at this small overlap ratio. However, this phenomenon is weakened as the overlap ratio is further increased suggesting a deteriorated performance of the rotor. Observations of the flow inside the rotor indicate an increased recirculating region at such large overlap ratios, which also suggests a reduced aerodynamic efficiency for rotors with large overlap. 相似文献
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液力变矩器叶栅系统测量方法 总被引:4,自引:2,他引:2
文章介绍了对液力变矩器工作轮的测绘,根据测量出叶片与内外环交线的坐标及叶片安放角度参数(叶片的进出口安放角),检查所生产的工作轮叶栅系统参数是否与设计图纸一致,对改进设计并提高液力变矩器的匹配性能提出一种较好的方法。 相似文献
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基于CALS及Surpac-FLAC3D耦合技术的 复杂空区稳定性分析 总被引:5,自引:0,他引:5
由于受地质条件和探测技术的限制,传统探测方法很难获得复杂空区精确的实际空间分布形状,由此得到的空区用于建立数值分析模型显得过于粗糙,在此基础上进行空区稳定性分析的可靠性程度不高。采用空区激光自动扫描系统(CALS)对复杂空区进行激光扫描,在获得精准三维点云数据的基础上,运用Surpac软件模拟出空区的三维地质模型,通过耦合方法可以在FLAC3D中生成与实际空区空间分布一致的数值模型,提高复杂空区稳定性计算的准确性和可靠性。选取三道庄露天矿的地下空区作为工程实例,利用CALS获得不规则空区的实际空间边界。在此基础上,运用Surpac进行三维块体模拟,研究Surpac与FLAC3D模型耦合技术,成功地将三维模型数据导入FLAC3D中,结合现场实际勘测的围岩力学参数,对空区进行静力计算,分析空区的稳定性。 相似文献
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本文根据已有的三维瞬态风场混合数值模拟方法,首先利用k-ε湍流模型对风力发电机叶片周边的时均湍流场进行CFD数值模拟,用ESDU推荐的方法计算了叶片附近的Reynolds应力张量,并修正叶片周边风场的脉动风功率谱密度函数。基于随机流场生成方法逐点模拟了叶片周边的三维脉动风速场,为今后进行叶片脉动荷载的求解奠定了基础。 相似文献