R22,R407C和R410A热泵专用涡旋式压缩机研究

分析多种热泵制冷剂物理性质,并对热泵用涡旋式压缩机运行特性进行分析。采用新设计的热泵专用涡旋式压缩机进行R22,R407C与R410A性能测试,结果表明:R410A和R407C制冷剂均可以替代R22制冷剂在热泵系统中使用;R410A与R22在制热能力、排气温度及运行范围方面相近;R407C的制热能力高于R22和R410A,运行范围相对较宽。     

R410A商用“煤改电”涡旋压缩机及系统设计分析

目前空气源热泵技术研究热点已从家用转向商用,产品所用制冷剂部分由R22转向R410A,基于上述变化,热泵用涡旋压缩机及系统设计有必要进行优化。本文分析了商用"煤改电"涡旋压缩机及系统在热泵工况下运行状态,从制冷剂物性及运行影响因素阐述了R410A商用"煤改电"产品需要优化设计内容,从机械部品强化及表面处理、喷射方案及控制方式、压缩机回液影响及规避措施等方面进行了分析,提出切实可行的优化方案。     

R32制冷剂空调压缩机应用试验研究

R22 制冷剂替换在即,R32 制冷剂是一种潜在的且经济的替代制冷剂.本文通过分析R32制冷剂的物理性质和理论热工循环参数,并采用空调用涡旋式压缩机进行试验测试,同时与 R410A 制冷剂进行试验对比.试验结果表明,R32 制冷剂替代当前的 R22 制冷剂作为空调制冷剂应用,对于空调用涡旋式压缩机来说,其整体表现与 R410A 制冷剂相类似.但为了取得更好的性能和可靠性,压缩机应针对 R32 制冷剂在空调工况应用时压力高、排气温度高的特点进行设计改进.     

低GWP替代制冷剂R452B和R513A研究

本文列举了制冷及热泵系统市场主流制冷剂R410A和R134a及其低GWP环保替代制冷剂R452B和R513A的特性参数。并基于压缩机测试结果,对比分析了主流制冷剂及其替代制冷剂在压缩机设计不变更前提下质量流量、制冷量、功率及制冷效率这些主要参数的变化趋势。最后得出结论:R452B和R513A作为替代R410A和R134a的低GWP制冷剂,在压缩机及系统不变更或少变更的情况下,可以满足客户的需求。     

R134a与R410A在空调工况下的性能比较

传统制冷剂R22的替代已是大势所趋.本文着重对R22的替代制冷剂R134a与R410A的传热、阻力压降特性进行实验比较研究,认为R410A在传热、阻力压降特性方面比R134a优良,作为R22的替代制冷剂,R410A应比R134a更有竞争力.     

R410A与R22制冷压缩机性能试验装置的对比

对制冷剂R410A与R22的热物性进行比较,并对分别以R410A和R22为工质的制冷压缩机性能试验装置进行对比分析,为建立以R410A为工质的制冷压缩机性能试验装置提供技术支持。     

不同混合比下丙烷和二氟乙烷替代R22理论研究

针对目前替代R22应用比较广泛的R407C和R410A存在的一些问题，提出一种由丙烷R290和二氟乙烷R152a组成的混合制冷剂来替代R22，分析该混合制冷剂的环境影响指数、安全特性和润滑油等问题，并针对不同配比情况下的温度滑移特性、热力学特性和循环特性进行了理论研究，与R407C和R410A进行了对比，得出R290质量分数在50％～90％之间时组成的混合制冷剂是一种对环境危害很小，温度滑移很小，具有合适的压比和COP，润滑特性很好的优良近共沸制冷剂，用于替代R22优于R407C和R410A。     

制冷剂R32的性能及其在空调机上的应用研究

介绍R32、R22和R410A三种制冷剂的物理性质和热力学性能,从理论分析方面,分析R32替代R22和R410A的可行性,同时,通过在水冷单元式空调机组分别采用三种制冷剂进行实验对比测试,研究这三种制冷剂在空调制冷系统中实际应用的性能对比,从而从实际应用方面,分析R32替代R22和R410A的可行性。     

滚动转子式R32压缩机开发

R32制冷剂与R410A制冷剂主要物性参数接近,是R410A的热门替代物,但R32制冷剂具有与R410A冷冻机油不相溶,以及压缩机排气温度高的特点。本文针对R32的特点开发R32压缩机专用冷冻机油,并研究采用吸气带液方式降低压缩机排气温度及其对压缩机可靠性的影响。     

R32变频压缩机的特性研究

R32冷媒相对于R410A具有高性能、低GWP的特点,是一种理想的替代制冷剂。本文对比分析了R32和R410A的冷媒物性,对R32变频压缩机的特性进行实验研究,试验结果表明,相同条件下,R32变频压缩机的制冷量比R410A提高7.5%~10%,COP提高2%~5%。     

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.     

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.……     

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 ...     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.