制冷空调用换热器研究进展

为实现制冷空调行业的节能减排目标，研究具有轻量化、小型化和高效化的制冷空调用换热器至关重要。本文主要介绍强化换热技术在制冷空调用换热器中的应用，包括风冷式换热器、水冷式换热器和蒸发式冷凝器，以及适应低制冷剂充注量、低GWP工质的紧凑型高效换热器的研发进展，为换热器的优化设计提供借鉴。     

我国板翅式换热器技术进展

阐述了３０年来，我国在板翅式换热器设计，制造和修补与防护等方面所取得的进步，无熔剂真空钎焊取代盐裕浸渍钎焊和８．０ＭＰａ高压板翅式换热器的开发是我国板翅式换热器制造技术上重大突破，总体技术水平达到或接近世界先进水平，最后展望板翅式换热器的前景和发展方向。     

国内外制冷空调用换热器的研究进展

本文总结了制冷空调用换热器的研究成果,指出了换热器研究总的趋势是：传热强化的研究,新型紧凑式换热器的开发与研究,以及换热器的计算模拟技术和设计方法学的研究,并且对管式换热器、板式换热器及板翅式换热器的研究进展分别进行了较为全面地阐述。     

平行流换热器在空调机上的应用研究

介绍全铝平行流换热器与传统铜管套翅片式换热器的结构区别,并从结构上分析全铝平行换热器的寿命、换热性能、阻力、重量等方面比传统铜管套翅片式换热器优化的情况,同时,通过在风冷式空调机上的测试,和传统铜管套翅片式换热器进行换热性能和空调系统性能对比,探讨平流式换热器在风冷式空调机上的应用可行性,为今后平行流换热器在风冷式空调...     

换热器管焊接开裂分析

换热器管子在焊接过程中产生开裂。对开裂管的化学成分、力学性能、断口及金相组织进行了检验与分析。结果表明，换热器管开裂是由管子存在原始裂纹所引起的。     

液氮发动机换热器的结霜研究

液氮汽车换热器的性能决定着液氮发动机的工作效率.分析了结霜对换热器性能的影响,阐述了换热器结霜的数学过程,并对如何避免换热器的结霜进行研究.提出了两种新型的避免结霜方法:采用预混和式换热器和改变翅片间距.通过试验发现这两种方法可以有效的防止换热器的结霜,提高换热器的汽化效率.     

低温换热器的Yong效率分析

分析了低温换热器中传热过程的热力学特性，定义了低温换器传热Ｙｏｎｇ效率，得到了Ｙｏｎｇ效率的计算式，讨论了传热单元数，介质热容量比等参数对低温换热器Ｙｏｎｇ效率的影响，比较了各种流型低温热器Ｙｏｎｇ效率的相对大小，给出了使Ｙｏｎｇ效率达最大值的最佳热容量比的计算方法。     

干盘管换热器与湿盘管换热器热工性能试验研究

传统空调末端换热器的设计工况一般为湿工况,随着建筑节能和室内空气品质要求的提高,温湿度独立控制和水蒸发冷却空调系统技术的逐步推广,干盘管换热器开始在工程系统中直接进行应用。这里利用铜管套翅片换热器的实验结果,采用综合制冷性能系数评价方法对干盘管换热器和湿盘管换热器热工性能进行了分析比较和评价,并提出在关注节能要求的同时,应关注换热器金属材料的消耗问题,供广大暖通空调行业人员参考。     

对提高换热器热效率的探讨

节约能源是当今世界的一种重社会意识,世界各国下大力量寻找新的能源以及在节约能源上研究新途径,换热设备的研究受到了高度重视。换热器的换热技术的研究,主集中在对换热器内流体流态变化以及对各部件的参数优化研究两方面,换热器内部流体的流动状态是影响换热器综合l生能的重因素。本文叙述了换热器提高热效率的几个因素,以及介绍当前常用的几种换热器,并对换热器研究存在几个不足进行阐述,并对换热器的前景进行了展望。     

石墨换热器的制造工艺及其特点

一基本情况石墨换热器是一种重要的工业设备,它具有一系列的优异性能:传热性能好,机械强度高,耐腐蚀性强,结构简单、制造方便,成本低等,广泛应用于化工、化肥、农药、食品、轻工、化纤、冶金等工业部门。世界上第一台石墨换热器的诞生是1934年由德国采用电极石墨制成的板式石墨换热器,三年后美国又研制成功了列管式石墨换热器。石墨换热器的应用有力地促进了当时盐酸和治炼工业的发展。从六、七十年代以来,石墨换热器的制造与应用发展很快,     

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.……     

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...     

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.     

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.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from