双向MEMS膨胀阀及其在电动大巴热泵系统中的应用

为克服步进电机式的电子膨胀阀在汽车空调上易失步问题,以及热力膨胀阀热惰性不适应变频压缩机的缺点,同时为了满足新能源汽车热泵空调的要求,本文提出一种基于热驱动的双向MEMS膨胀阀,MEMS膨胀阀非步进电机式的驱动方式确保其不会受到汽车振动的影响,同时其线性快速响应速度能够解决热力膨胀阀热惰性的缺点。采用空调的测试标准,利用一台电动大巴热泵系统进行热力膨胀阀和MEMS膨胀阀的对比试验,结果显示,采用MEMS膨胀阀的电动大巴热泵系统能效提升14.7%,同时完成装车试验中行驶200 km无故障的要求。     

R410A直流变频列间空调系统变流量调节性能分析及试验研究

通过对计算机房微模块中的变频列间空调在对环保型制冷剂替代R22对比应用进行说明及实验分析压缩机转速、电子膨胀阀开度、EC风机调节、室内外环境变化等对变频空调系统性能影响,有助于后期优化产品设计及控制逻辑,以达到最佳节能环保的效果。     

电子膨胀阀在小型中央空调系统中的应用研究

本文介绍在小型中央空调系统中普遍使用的电子膨胀阀，分析了电子膨胀阀在空调系统中的作用，提出了一种行之有效的控制方法，最后还提出了改进的建议。     

电子膨胀阀在定频制冷系统上的应用

压缩机制冷系统,现在有使用定频压缩机的定频制冷系统和使用变频压缩机的变频制冷系统,变频制冷系统中的变频压缩机根据设备当前温度与设定目标温度的差值大小调节压缩机的转速,从而使压缩机输出的制冷量增大或减小。而在使用定频压缩机的定频制冷系统中,节流元件用热力膨胀阀或是毛细管时,其制冷量的输出几乎不变,为保证制冷设备内的温度或空调房间的温度保持恒定,压缩机需频繁开停,笔者针对上述问题,对电子膨胀阀在定频制冷系统上的应用进行了研究。     

智能型全天候高效节能变频空调器节流元件的选取

变频空调器潜在的节能优势能否充分发挥,关键在于其所选用的节流元件。本文对毛细管、电子膨胀阀及热力膨胀阀的性能进行对比分析,并对变频空调器分别采用电子膨胀阀和双向热力膨胀阀的性能进行测试。分析结果表明,双向热力膨胀阀具有智能型自适应调节功能,是变频空调器的理想而实用的节流元件。     

多联机系统中电子膨胀阀运行特性研究

本文介绍电子膨胀阀应用在一套多联机系统的运行特性，从理论上建立物理和数学模型，理论模型表明电子膨胀阀具有良好的调节能力。通过对本系统的电子膨胀阀的一系列测试，结果验证了多联机电子膨胀阀的良好的调节特性和节能效果，本实验结果对电子膨胀阀应用具有参考意义。     

一拖多中央空调系统与水冷机组中央空调系统的技术及经济性分析

在目前建筑市场上,集休闲、娱乐、健身、办公等功能于一体的商用建筑越来越多,人们对空调的舒适度、智能控制等要求也随之提高。水冷机组中央空调系统由于其使用的经济性及占用较大室内空间等缺点不被此类建筑物广泛应用,而变频一拖多中央空调系统以其自身卓越的性能及众多的优点得到了快速发展。     

“制冷空调用直动式电子膨胀阀”行业标准通过评审

1999年 11月 13日 ,全国冷冻设备标准技术委员会一届二次工作会议上通过了“制冷空调用直动式电子膨胀阀”行业标准。该标准由机械工业部合肥通用机械研究所提出并归口 ,委托上海俊乐制冷自控元件有限公司起草。该标准的制订填补了国内电子膨胀阀元件标准的空白 ,对突破日本等国的技术垄断 ,推动国内空调制造技术的发展起到重要作用。　　电子膨胀阀是变频空调设备的关键元件 ,它的调节控制功能与变频调速压缩机相匹配 ,起到节能与降低噪声作用。上海俊乐公司在吸收国外高新技术基础上 ,进行了电子膨胀阀产品的开发 ,具备了一定的批量生产能…     

浅谈机组设计中电子膨胀阀的选择

通过对于电子膨胀阀的选型研究,提高电子膨胀阀在大型空调机组中的适用范围,有利于机组的精确控制。使电子膨胀阀与机组更有效地匹配,有利于扩大机组的运行范围。     

空调用电子膨胀阀流量特性研究

本文通过实验研究了电子膨胀阀流量与开度的关系。实验表明家用变频空调器中的电子膨胀阀开度与制冷量近似成线形关系，从而为电子膨胀阀的正确选用和变频空调器性能的进一步优化提供理论依据。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...