In the present paper;two models of the input shaft for a Longitudinal Mounted four Speed Automotive Automatic Transmission for the first time were introduced to describe the input shaft critical loads. In the first mo...In the present paper;two models of the input shaft for a Longitudinal Mounted four Speed Automotive Automatic Transmission for the first time were introduced to describe the input shaft critical loads. In the first model;the DC (Direct Clutch) connects two gears together. This gives no change in the set torque (the set output torque equal to the set input torque). In the second model;the ODB (Over Drive Brake) fixes one element of the planetary set. This is resulting, the gear set gives reduction ratio (the set output torque is not equal to the set input torque). So, the transmission input shaft is worked under two different working operating conditions of torque. Also, it is loaded by a two vertical loads which are coming from the turbine and planetary set loads respectively. They are shown that there are three critical combinations of forces (contact force, shear force, and normal force) applied on the input shaft. The critical forces can be possibility exist three types of cracks for the input shaft cross section they are: transverse (torsion stress), longitudinal (bending stress), and vertical (shear stress). The three cracks are studied in this article. The article considers three stress factors: shearing torsion stress, shear stress, and bending stress.展开更多
The torque and bending moment acting on a flexible overhung shaft in a gas–liquid stirred vessel agitated by a Rushton turbine and three different curved-blade disk turbines(half circular blades disk turbine, half el...The torque and bending moment acting on a flexible overhung shaft in a gas–liquid stirred vessel agitated by a Rushton turbine and three different curved-blade disk turbines(half circular blades disk turbine, half elliptical blades disk turbine, and parabolic blades disk turbine) were experimentally measured by a customized moment sensor. The results show that the amplitude distribution of torque can be fitted by a symmetric bimodal distribution for disk turbines, and generally the distribution is more dispersive as the blade curvature or the gas flow rate increases. The amplitude distribution of shaft bending moment can be fitted by an asymmetric Weibull distribution for disk turbines. The relative shaft bending moment manifests a "rising-falling-rising" trend over the gas flow number, which is a corporate contribution of the unstable gas–liquid flow around the impeller, the gas cavities behind the blades, and the direct impact of gas on the impeller. And the "falling" stage is greater and lasts wider over the gas flow number for Rushton turbine than for the curved-blade disk turbines.展开更多
近年来,风能资源大力发展,风火打捆经直流送出成为中国目前及未来开发和利用的主要方式,风电机群和高压直流输电(high voltage direct current,HVDC)对同步发电机组(synchronous generator,SG)轴系扭振各模态电气阻尼的影响规律有待深...近年来,风能资源大力发展,风火打捆经直流送出成为中国目前及未来开发和利用的主要方式,风电机群和高压直流输电(high voltage direct current,HVDC)对同步发电机组(synchronous generator,SG)轴系扭振各模态电气阻尼的影响规律有待深入研究。针对直驱风电机群、火电机组和直流输电,建立了系统的线性化模型,分析了接入设备对火电机组电气阻尼的交互耦合关系和风火打捆经直流送出系统中火电机组轴系扭振的机理。基于复转矩系数法,研究了风电机群运行风速、控制参数和直流输电输送功率、控制参数等因素对同步发电机组电气阻尼系数的影响。最后,在PSCAD/EMTDC中搭建风火打捆经直流送出系统的时域仿真模型,通过时域仿真和时频分析,验证了电气阻尼系数分析结果的有效性。展开更多
针对一种由高压直流输电(high voltage DC,HVDC)系统引起汽轮发电机轴系扭振现象的机理,首先分析逆变站所连交流系统扰动时,逆变站换流阀组的换相失败过程,分析得出逆变站换流阀组换相失败引起整流站附近的汽轮发电机轴系扰动,引起发电...针对一种由高压直流输电(high voltage DC,HVDC)系统引起汽轮发电机轴系扭振现象的机理,首先分析逆变站所连交流系统扰动时,逆变站换流阀组的换相失败过程,分析得出逆变站换流阀组换相失败引起整流站附近的汽轮发电机轴系扰动,引起发电机转矩的变化,而HVDC系统不恰当的控制,为扰动提供负阻尼,从而形成一种正反馈性质的扭振相互作用,最终使得发电机出现轴系扭振。采用时域与频域相结合的仿真方法计算复转矩系数,并仿真再现由HVDC系统引起的轴系扭振现象。研究成果为交直流互联系统次同步振荡预测和分析提供理论依据。展开更多
文摘In the present paper;two models of the input shaft for a Longitudinal Mounted four Speed Automotive Automatic Transmission for the first time were introduced to describe the input shaft critical loads. In the first model;the DC (Direct Clutch) connects two gears together. This gives no change in the set torque (the set output torque equal to the set input torque). In the second model;the ODB (Over Drive Brake) fixes one element of the planetary set. This is resulting, the gear set gives reduction ratio (the set output torque is not equal to the set input torque). So, the transmission input shaft is worked under two different working operating conditions of torque. Also, it is loaded by a two vertical loads which are coming from the turbine and planetary set loads respectively. They are shown that there are three critical combinations of forces (contact force, shear force, and normal force) applied on the input shaft. The critical forces can be possibility exist three types of cracks for the input shaft cross section they are: transverse (torsion stress), longitudinal (bending stress), and vertical (shear stress). The three cracks are studied in this article. The article considers three stress factors: shearing torsion stress, shear stress, and bending stress.
基金Supported by the National Key R&D Program of China(2017YFB0306704)the National Natural Science Foundation of China(21676007)
文摘The torque and bending moment acting on a flexible overhung shaft in a gas–liquid stirred vessel agitated by a Rushton turbine and three different curved-blade disk turbines(half circular blades disk turbine, half elliptical blades disk turbine, and parabolic blades disk turbine) were experimentally measured by a customized moment sensor. The results show that the amplitude distribution of torque can be fitted by a symmetric bimodal distribution for disk turbines, and generally the distribution is more dispersive as the blade curvature or the gas flow rate increases. The amplitude distribution of shaft bending moment can be fitted by an asymmetric Weibull distribution for disk turbines. The relative shaft bending moment manifests a "rising-falling-rising" trend over the gas flow number, which is a corporate contribution of the unstable gas–liquid flow around the impeller, the gas cavities behind the blades, and the direct impact of gas on the impeller. And the "falling" stage is greater and lasts wider over the gas flow number for Rushton turbine than for the curved-blade disk turbines.
文摘近年来,风能资源大力发展,风火打捆经直流送出成为中国目前及未来开发和利用的主要方式,风电机群和高压直流输电(high voltage direct current,HVDC)对同步发电机组(synchronous generator,SG)轴系扭振各模态电气阻尼的影响规律有待深入研究。针对直驱风电机群、火电机组和直流输电,建立了系统的线性化模型,分析了接入设备对火电机组电气阻尼的交互耦合关系和风火打捆经直流送出系统中火电机组轴系扭振的机理。基于复转矩系数法,研究了风电机群运行风速、控制参数和直流输电输送功率、控制参数等因素对同步发电机组电气阻尼系数的影响。最后,在PSCAD/EMTDC中搭建风火打捆经直流送出系统的时域仿真模型,通过时域仿真和时频分析,验证了电气阻尼系数分析结果的有效性。
文摘针对一种由高压直流输电(high voltage DC,HVDC)系统引起汽轮发电机轴系扭振现象的机理,首先分析逆变站所连交流系统扰动时,逆变站换流阀组的换相失败过程,分析得出逆变站换流阀组换相失败引起整流站附近的汽轮发电机轴系扰动,引起发电机转矩的变化,而HVDC系统不恰当的控制,为扰动提供负阻尼,从而形成一种正反馈性质的扭振相互作用,最终使得发电机出现轴系扭振。采用时域与频域相结合的仿真方法计算复转矩系数,并仿真再现由HVDC系统引起的轴系扭振现象。研究成果为交直流互联系统次同步振荡预测和分析提供理论依据。
