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磁流变传动装置多种工况下热结构场研究 被引量:3
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作者 陈松 杨晶 黄金 《机械传动》 北大核心 2019年第8期18-24,共7页
针对高温条件下磁流变液剪切应力、热磁化强度、黏度和流变特性显著降低,以及热应力对磁流变液链化结构的破坏,严重影响磁流变传动装置性能的问题,基于剪切模量与磁场强度的非线性关系,推算了磁场作用下磁流变液固化状态的弹性模量;研... 针对高温条件下磁流变液剪切应力、热磁化强度、黏度和流变特性显著降低,以及热应力对磁流变液链化结构的破坏,严重影响磁流变传动装置性能的问题,基于剪切模量与磁场强度的非线性关系,推算了磁场作用下磁流变液固化状态的弹性模量;研究了在滑差和励磁线圈功率损失工况下磁流变液的温度、热变形以及等效热应力分布规律;探讨了滑差功率、电流、间隙宽度和励磁线圈绕组级数对其的影响。研究结果表明,滑差功率和励磁线圈生热都会造成磁流变液温度显著升高,由此产生的热变形对结构影响较小,而等效热应力影响较大;磁流变液工作间隙与非工作间隙的等效热应力分布存在明显差异;可在滑差和电流不变的情况下通过改变间隙宽度和绕组级数提高磁流变传动装置的性能。 展开更多
关键词 磁流变液 温度 滑差生热 电流发热 热结构场
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涡流效应在励磁系统中产生的影响及解决办法
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作者 刘志刚 王芳 《中国新技术新产品》 2015年第21期67-67,共1页
本文主要介绍了涡流效应的概念,涡流效应的原理,涡流效应容易造成的后果及影响,根据某现场用的励磁系统的运行情况,以实例说明了现场励磁系统由于涡流效应出现情况,并且根据涡流效应的原理,进行了分析,根据涡流效应的原理及产生的条件,... 本文主要介绍了涡流效应的概念,涡流效应的原理,涡流效应容易造成的后果及影响,根据某现场用的励磁系统的运行情况,以实例说明了现场励磁系统由于涡流效应出现情况,并且根据涡流效应的原理,进行了分析,根据涡流效应的原理及产生的条件,提出了解决方案,并且介绍了应用的情况,最后提出了励磁系统的设计、制造、运行时应注意的问题。 展开更多
关键词 涡流效应 电流发热 励磁系统
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飞机电动机过热研究
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作者 赵文智 韩文秀 《中国民航学院学报》 2006年第3期38-40,共3页
首先从飞机防火角度,用对称分量法分析了航空电机在不对称电源下的发热情况,推导了发热电流的公式,以此作为数学模型,解释缺相时电机很快烧毁的物理现象。最后提出了防止航空三相电动机过热与起火的方法,包括采用电机在线状态监控、主... 首先从飞机防火角度,用对称分量法分析了航空电机在不对称电源下的发热情况,推导了发热电流的公式,以此作为数学模型,解释缺相时电机很快烧毁的物理现象。最后提出了防止航空三相电动机过热与起火的方法,包括采用电机在线状态监控、主动维护、增加有效的保护装置等。 展开更多
关键词 飞机防火 电动机 缺相 发热电流
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基于TRS-1000温升试验系统的触头温升检测方法
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作者 刘申 《低压电器》 北大核心 2010年第20期58-60,共3页
温升试验作为低压开关电器型式试验项目及其中的一项,对于考察开关电器触头、放电室等其他部件的性能有很重要的作用。基于TRS-1000的温升试验系统总结了触头温升的检测方法,既能提高触头温升的检测精度,又能加快试验的检测效率。
关键词 温升 约定发热电流 热电偶 温度测量通道
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某选厂重型卸料小车电机控制系统改造
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作者 张红庆 《现代矿业》 CAS 2015年第12期234-236,共3页
某选矿厂磨选作业给矿重型卸料小车具有重载起车运行负载转距较大的负载特性,加之较短的运转周期,在生产运行过程中连续出现小车驱动链条损坏、减速机电机轴侧滚键等故障,影响设备使用寿命和生产的正常进行。对造成故障的原因进行分析,... 某选矿厂磨选作业给矿重型卸料小车具有重载起车运行负载转距较大的负载特性,加之较短的运转周期,在生产运行过程中连续出现小车驱动链条损坏、减速机电机轴侧滚键等故障,影响设备使用寿命和生产的正常进行。对造成故障的原因进行分析,选择外壳防护等级为IP54封闭型Y系列驱动电机,并对电机安全运行时的电流判定进行研究。在此基础上,对电机控制系统提出了3种解决方案。其中系统增加软启动器不适用于重型卸料小车重载频繁起车操作,增加自动定位系统则存在投资大、维修难的问题。系统增加变频器,可实现小车重载频繁起车对电机的要求,总体经济性较好。考虑到变频器高振谐波及其与电缆的距离的影响,采用高一级变频和容量变频器,并设计为变频控制柜。应用实践结果表明,重型卸料小车电机控制系统增加变频器后,能从根本上解决设备安全运行隐患,大幅度降低停车故障率,对于保证产能、提高厂矿经济效益具有重要作用。该选厂重型卸料小车电机控制系统采用变频装置参与设备起停控制的改造经验,可为其他矿山类似卸料小车控制系统的优化改造提供借鉴。 展开更多
关键词 等效发热电流 软起动器 变频器 小车自动定位系统
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Excess Heat Triggered by Different Current in a D/Pd Gas-Loading System 被引量:3
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作者 Xin Lu Bingjun Shen +3 位作者 Lihong Jin Xinle Zhao Hongyu Wang Jian Tian 《Journal of Energy and Power Engineering》 2013年第7期1299-1303,共5页
In order to study the relationship between the triggering current, deuterium pressure and the excess heat, a series of experiments were made in a D/Pd gas-loading system. By comparing the system constants (k = AT//kP... In order to study the relationship between the triggering current, deuterium pressure and the excess heat, a series of experiments were made in a D/Pd gas-loading system. By comparing the system constants (k = AT//kP) in both nitrogen and deuterium atmosphere we found an optimum current (8 A) and a deuterium pressure (9 x 104 Pa) in which the system could release a maximum excess power (more than 80 W). The reproducibility was 16/16 and the excess energy released in the longest experiment was about 300 MJ within 40 days, which was corresponding to 104 eV for each palladium atom. Analysis of the palladium surface with a SEM (scanning electron microscopy) and an EDS (energy dispersive spectrometer) revealed that some new surface topographical feature with concentrations of unexpected elements (such as Ag, Sn, Pb and Ca) appeared after the current triggering. The results implied that the excess heat might come from a nuclear transmutation. 展开更多
关键词 Current triggering deuterium pressure D/Pd gas-loading system excess heat.
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Tides and Wind-Driven Circulation in the Tropical and Southern Atlantic Ocean:The BRAZCOAST System
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作者 Ricardo de CAMARGO Joseph HARARI 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第5期476-480,共5页
The Brazilian coast is characterized by different tidal regimes and distinct meteorological influences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical disturbance... The Brazilian coast is characterized by different tidal regimes and distinct meteorological influences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical disturbances; the southern portion has smaller tidal amplitudes and is frequently influenced by extratropical cyclone activity. Besides these aspects, many features regarding current structure and behavior are also present, such as the equatorial system of currents, the subtropical gyre and the corresponding western boundary currents, and the Brazil-Malvinas confluence region. Within this context, efforts were made to develop the BRAZCOAST system, capable of describing the processes that determine the oceanic circulation from large to coastal scales. A customized version of the Princeton Ocean Model(POM) was implemented in a basin-scale domain covering the whole of the tropical and southern Atlantic Ocean, with 0.5° spatial resolution, as well as three nested grids with(1/12)° resolution covering the different parts of the Brazilian shelf, in a one-way procedure. POM was modified to include tidal potential generator terms and a partially-clamped boundary condition for tidal elevations. The coarse grid captured large-scale features, while the nested grids detailed local circulations affected by bathymetry and coastal restrictions. An interesting aspect at the coarse grid level was the relevance of the Weddell Sea to the location of the tidal amphidromic systems. 展开更多
关键词 TIDES wind-driven circulation tropical Atlan-tic South Atlantic Princeton Ocean Model
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Optimizing Geothermal Energy Resource
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作者 Mohamad Kharseh Mohammed Al-Khawaja 《Journal of Mechanics Engineering and Automation》 2015年第12期667-675,共9页
Unlike other types of renewable energy resources, geothermal energy provides a stable source of energy as it can be exploited regardless of meteorological conditions. Using organic cycle, geothermal energy can be util... Unlike other types of renewable energy resources, geothermal energy provides a stable source of energy as it can be exploited regardless of meteorological conditions. Using organic cycle, geothermal energy can be utilized for power generation. In such systems, the heat is exchanged between the surrounding rock mass and transport fluid. Consequently, the temperature of extracted geofluid from the well decreases with the time in accordance with the working parameters. Those parameters includeenergy extraction rate, temperature difference between inlet and outlet of the well, and the thermal conductivity of the ground. Current work, aims to develop a reliable computer model to specify the optimal working parameters so that the geofluid temperature will not reach a low value that is not acceptable for electricity generation, and the energy availability of geothermal resource is maximized. In the current study the ground thermal properties, the geothermal gradient and well dimensions are based on realistic data in Qatar and neighboring countries. The proposed model was developed for different heat extraction rate, different ground thermal properties, and for varied temperature difference between inlet and outlet of the well. Simulation shows that selecting the optimal working parameters can increase the availability of geothermal resource significantly. 展开更多
关键词 Geothermal resource heat transfer optimizing computer simulation exergy.
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Oscillatory Flow in Thermoacoustic Sound Wave Generator 被引量:2
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作者 Masayasu HATAZAWA 《Journal of Thermal Science》 SCIE EI CAS CSCD 2006年第1期92-96,共5页
Oscillatory flow in a thermoacoustic sound wave generator is described. The thermoacoustic sound wave generator plays an important role in thermoacoustic equipment. The heat exchange between the working fluid and the ... Oscillatory flow in a thermoacoustic sound wave generator is described. The thermoacoustic sound wave generator plays an important role in thermoacoustic equipment. The heat exchange between the working fluid and the stack, the acceleration and deceleration of the working fluid and viscous friction loss both in the stack and in the resonance tube influence the performance of the thermoacoustic sound wave generator. Particularly, oscillatory flow significantly influences the heat exchange mechanism between the working fluid and the stack. Temporal changes in pressure and velocity are sinusoidal inside the resonance tube. Flow forms an oscillatory jet just behind the tube outlet, and becomes intermittent far downstream outside the resonance tube. The open-end corrections of 0.63R, that is, the region where oscillatory flow characteristics are maintained downstream in spite of being outside the tube outlet, are confirmed by velocity measurements and flow visualization. Also, they are almost equal to acoustical theoretical results. 展开更多
关键词 thermoacoustic phenomena sound wave generator oscillatory flow.
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Flexible thermocells for utilization of body heat 被引量:3
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作者 Hyeongwook Im Hyung Geun Moon +3 位作者 Jeong Seok Lee In Young Chung Tae June Kang Yong Hyup Kim 《Nano Research》 SCIE EI CAS CSCD 2014年第4期443-452,共10页
Plastic thermo-electrochemical ceils (thermocells) involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harves... Plastic thermo-electrochemical ceils (thermocells) involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. Plastic thermocells that consist of all pliable materials such as polyethylene terephthalate (PET), fabrics, and wires are flexible enough to be wearable on the human body and to be wrapped around cylindrical shapes. The performance of the thermocells is enhanced by incorporating carbon nanotubes into activated carbon textiles, due to improved charge transfer at the interface. In cold weather conditions (a surrounding temperature of 5 ℃), the thermocell generates a short-circuit current density of 0.39 A/m2 and maximum power density of 0.46 mW/m2 from body heat (temperature of 36℃). For practical use, we have shown that the thermocell charges up a capacitor when worn on a T-shirt by a person. We also have demonstrated that the electrical energy generated from waste pipe heat using a serial array of the thermocells and voltage converters can power a typical commercial light emitting diode (LED). 展开更多
关键词 wearable thermocell body heat waste heat recovery carbon nanotubes activated carbon textile porous electrode
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