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《国际科技文献速递:通用机械》     2023年  第 12 期

              阀门       风机       压缩机       真空、干燥、冷却、空分机械       减变速机


【标题】Methodology for generating a general profile of asymmetrical rotors of twin-screw vacuum pumps with point meshing feature by a pre-defined sealing line

【类型】 期刊

【关键词】 Pre-defined sealing line; point meshing feature; asymmetrical rotor; twin-screw vacuum pump; optimization profile; variable pitch; variable cross-section; TOOTH PROFILE; DESIGN; ERRORS

【参考中译】 预定义密封线;点啮合特征;不对称转子;双螺杆真空泵;优化齿形;变螺距;变截面;齿形;设计;误差

【作者】 Hoang, Minh-Thuan; Tran, The-Van

【摘要】 The sealing line is one of the key influences on twin-screw rotor vacuum pump performance. The design of a rotor profile based on a sealing line for an asymmetrical rotor of a vacuum pump can be studied further to generate varied rotor profiles and improve pump performance. Therefore, this study proposes a mathematical model for a pre-defined sealing line to design and optimize varied rotor profiles of vacuum pumps. The general sealing line, pre-defined by explicit equations of straight lines and elliptic curves, is proposed to generate various rotor profiles with different numbers of lobes. The functions for parameter variables of the pre-defined sealing line are constructed and directly variated along the rotor length to form the screw rotor with a variable pitch and a variable cross-section. The proposed pre-defined sealing line is also applied in the optimal design of a rotor profile to enhance pump performance. Numerical examples are performed to verify the flexibility and practicability of the proposed method.

【参考中译】 密封管路是影响双螺杆转子真空泵性能的关键因素之一。基于密封线的真空泵非对称转子型线的设计可以进一步研究,以产生不同的转子型线,提高泵的性能。因此,本研究提出了一种预定义密封线的数学模型,用于设计和优化真空泵的各种转子型线。提出了一种由直线和椭圆曲线的显式方程预先定义的通用密封线,以生成不同叶片数的不同转子型线。构造了预定义密封线参数变量的函数,并直接沿转子长度变化,形成变螺距、变截面的螺杆转子。所提出的预定义密封线也被应用于转子型线的优化设计,以提高泵的性能。数值算例验证了该方法的灵活性和实用性。

【来源】 Proceedings of the Institution of Mechanical Engineers, Part B. Journal of engineering manufacture 2023, vol.237, no.10

【入库时间】 2023/12/27



【标题】Valve design considerations in liquid hydrogen systems to prevent failure


【类型】 期刊

【关键词】 Graphite sealing; Fire safe design; Stem buckling and torsion; Finite element analysis (FEA); Cavity relief; Material proportional limit; Modulus of elasticity; RISK-ASSESSMENT; EMBRITTLEMENT; SEAL

【参考中译】 石墨密封;消防安全设计;阀杆屈曲和扭转;有限元分析(FEA);空穴消除;材料比例极限;弹性模量;风险评估;脆性;密封

【作者】 Sotoodeh, Karan; Gudmestad, Ove Tobias

【摘要】 Hydrogen has potential as an alternative source of energy (energy carrier) because it can be converted, stored, and used efficiently, with a wide range of applications. It can be created from renewable energy sources and can thus serve as storage of renewable energy like wind- and sun-power. It shall be noted that Hydrogen liquefies at -252.9 degrees C, so cryogenic systems and sophisticated insulation techniques are necessary. Control of the flow has always been carried out by valve assemblies in processing plants. The proper design of industrial valves in every industry, including hydrogen systems, can significantly improve the safety and reliability of the valves specifically, as well as the plant as a whole. An overview of various previous studies is presented in this paper, discussing important design concepts for cryogenic valves. The main research question is to determine what are the main design considerations for valves used in liquid hydrogen systems, to minimize the risk of leakage from the valves to ensure required safety. In this study, different aspects of valve design for liquid hydrogen are examined, such as selection of steel materials, steel wall thickness calculations, stem design, sealing material selection, fire-safe design, cavity over-pressure protection, and body and bonnet extension.

【参考中译】 氢作为一种替代能源(能源载体)具有潜力,因为它可以被有效地转化、储存和利用,具有广泛的应用前景。它可以从可再生能源中产生,因此可以作为可再生能源的存储,如风能和太阳能。应该注意的是,氢在-252.9摄氏度下液化,因此需要低温系统和复杂的绝缘技术。在加工厂中,流量的控制一直由阀门总成来执行。在每个行业,包括氢气系统,工业阀门的适当设计可以显著提高阀门的安全性和可靠性,以及整个工厂的安全性和可靠性。本文对以往的各种研究进行了综述,讨论了低温阀门的重要设计概念。主要的研究问题是确定液氢系统中使用的阀门的主要设计考虑因素是什么,以最大限度地减少阀门泄漏的风险,以确保所需的安全性。本研究从钢材选择、钢壁厚度计算、阀杆设计、密封材料选择、防火设计、型腔超压保护、阀体和阀盖延伸等方面对液氢阀门设计进行了研究。

【来源】 IJIDeM: International Journal on Interactive Design and Manufacturing 2023, vol.17, no.3

【入库时间】 2023/12/27



【标题】Is it worth investing in a car-drying blower?


【类型】 期刊

【作者】 Steve Fowler

【摘要】 USING power tools when working on a vehicle is usually about making the task easier or doing it quicker. That's not really the case with a car dryer, though, which is more about keeping the need to touch the bodywork to a minimum and preventing marring the finish with swirls and microscopic scratches. The idea is that, after washing and rinsing, you use the blower to blast away water rather than soaking the moisture up with a microfibre drying towel. The upside is less risk to your paint, but the downside is that doing the whole car takes longer than using a towel - particularly a big one like our test winner from Armor All.

【参考中译】 在车辆上工作时使用电动工具通常是为了让任务更容易或更快完成。然而,S的汽车烘干机可不是这样,它更多的是将接触车身的需要降到最低,并防止涡流和微小划痕破坏车身。其想法是,洗完和漂洗后,用吹风机吹走水分,而不是用超细纤维烘干毛巾吸收水分。优点是油漆风险较小,但缺点是整车烘干比使用毛巾需要更长的时间--特别是像我们来自Armor All的测试获胜者这样的大毛巾。

【来源】 Auto Express 2023

【入库时间】 2023/12/27



【标题】Preliminary Crankshaft Speed Assessment for a Reciprocating Hybrid Power Machine with Regenerative Heat Transfer in Compressor and Pump Modes


【类型】 期刊

【关键词】 reciprocating hybrid power machine; regenerative heat transfer; reciprocating compressor; reciprocating pump; crankshaft speed; injection pressure

【参考中译】 往复式混合动力机;蓄热式换热;往复式压缩机;往复泵;曲轴转速;喷射压力

【作者】 Shcherba V. E.

【摘要】 The crankshaft speed in a reciprocating hybrid power machine with regenerative heat transfer operating in pump mode and in compressor mode is considered. By analysis of the injection and suction processes, assuming that the maximum pressure losses in these processes are equal, a formula is derived for the crankshaft speed in pump mode with known crankshaft speed in compressor mode. In addition, the crankshaft speed in pump mode with known crankshaft speed in compressor mode is determined on the assumption that the pressure losses in injection and suction for compressor and pump modes are equal. By numerical analysis with water and air as the working media, the crankshaft speed in pump mode is expressed as a function of the crankshaft speed in compressor mode and the injection pressure. If the crankshaft speed in compressor mode is 2000–3000 rpm, the crankshaft speed in pump mode is found to be 100–150 rpm.

【参考中译】 考虑了在泵模式和压缩机模式下运行的具有再生热传递的往复式混合动力机器中的曲轴速度。通过对喷射和吸入过程的分析,假设这两个过程中的最大压力损失相等,在已知压缩机模式曲轴转速的情况下,推导出泵模式曲轴转速的计算公式。此外,在压缩机模式中曲轴速度已知的情况下,泵模式中的曲轴速度是在压缩机和泵模式的喷射和吸入中的压力损失相等的假设下确定的。以水和空气为工质,通过数值分析,将泵模式下的曲轴转速表示为压气机模式下的曲轴转速和喷油压力的函数。如果压缩机模式下的曲轴速度为2000-3000 rpm,则发现泵模式下的曲轴速度为100-150 rpm。

【来源】 Russian engineering research 2023, vol.43, no.5

【入库时间】 2023/12/27



【标题】Cryogenic and Dry Machining of Ti6Al4V Alloy for Evaluation of Microhardness, Thermal Loads, Microstructure, and Surface Quality


【类型】 期刊

【关键词】 cryogenic machining; microstructure; surface quality; thermal loads; Ti6Al4V alloy

【参考中译】 深冷加工;组织;表面质量;热负荷;Ti6Al4V合金

【作者】 Fallah Mohammad Meghdad; Jafarian Farshid

【摘要】 Cryogenic cooling is an efficient technology to facilitate the machining process of difficult-to-cut materials. Performing this process with nontoxic biocompatible liquid nitrogen is an eco-friendly operation which has recently received much attention due to its promising advantages. In the present work, a comparative study has been performed on the machining process of Ti6Al4V alloy using dry and cryogenic cooling approaches. So, the effect of machining parameters (cutting speed, feed rate, and depth of cut) is investigated on the process temperature and the surface integrity features such as surface roughness, microhardness, and grain size. The results revealed that the cryogenic technology decreases the cutting region temperature by about 30% which means applying less thermal loads on the machining samples. Also, among the process parameters, the feed rate has the greatest effect and the cutting speed has the least effect on the machining temperature. Based on the results, the cryogenic cooling has a successful effect on improving surface quality. It was also discovered that the cryogenic machining increases microhardness and decreases grain size compared to dry machining.

【参考中译】 低温冷却是一种高效的加工难加工材料的技术。使用无毒、生物相容的液氮进行这一过程是一种生态友好的操作,由于其具有前景广阔的优点,近年来受到了广泛的关注。本文对Ti6Al4V合金的干冷和深冷加工工艺进行了对比研究。因此,研究了加工参数(加工速度、进给速度和加工深度)对加工温度和表面粗糙度、显微硬度和晶粒度等表面完整性特征的影响。结果表明,深冷技术使切削区温度降低了约30%,这意味着对加工样品施加的热负荷更少。在各工艺参数中,进给速度对加工温度的影响最大,切削速度对加工温度的影响最小。结果表明,低温冷却在改善表面质量方面取得了成功。研究还发现,与干式加工相比,低温加工提高了显微硬度,减小了晶粒度。

【来源】 Journal of Materials Engineering and Performance 2023, vol.32, no.13

【入库时间】 2023/12/27



【标题】Optimization of the Gearbox Volume with a Specific Matlab GUI Program


【类型】 期刊

【关键词】 Gear Train; Gearbox Volume; GUI Software; Optimization

【参考中译】 轮系;变速箱体积;图形用户界面软件;优化

【作者】 Yazdani A.E.; Abyaneh S.

【摘要】 The optimization of any gear train is a challenging process, given the specifications of the mathematical model that explains its performance. This article discusses the design features and optimization of gear trains with spur gears with a specified GUI program based on Matlab coding. It will give a detailed outline of the selection of the design parameters, due to the governing equations and the selection of the optimal values in order to minimize the size of the gearbox with regard to the specific gears’ positions. Hence, after mathematical model development of the gear train, a GUI software is presented for the optimization process. It will then followed by a numerical example which has been compared and validated by the similar results of two other previously published studies for the same gearbox configuration and input data. The results show the effectiveness of the present method in the gearbox volume reduction.

【参考中译】 考虑到解释其性能的数学模型的规格,任何轮系的优化都是一个具有挑战性的过程。讨论了基于MatLab编码的特定图形用户界面程序的直齿圆柱齿轮传动的设计特点和优化设计。它将给出详细的设计参数的选择,根据控制方程和最优值的选择,以最大限度地减少变速箱相对于特定齿轮位置的尺寸。为此,在建立了轮系的数学模型后,提出了一个用于优化过程的图形用户界面软件。然后给出一个数值算例,该算例已经与之前发表的两个相同变速箱结构和输入数据的研究的类似结果进行了比较和验证。结果表明,该方法在齿轮箱体积缩小方面是有效的。

【来源】 International review of mechanical engineering 2022, vol.16, no.11

【入库时间】 2023/12/27


Auto Express《汽车快讯》
International review of mechanical engineering《国际机械工程评论》
Journal of Materials Engineering and Performance《材料工程与特性杂志》
Proceedings of the Institution of Mechanical Engineers《机械工程师学会会报B辑:工程制造杂志》
Russian engineering research《俄罗斯工程研究》