翅片管式换热器换热与压降特性的实验研究进展--关联式

概述目前国内外空调制冷行业中的普遍采用的几种不同翅片类型(平直翅片、波纹形、条缝形翅片、百叶窗形翅片)的换热及压降实验关联式及其影响因素，并对翅片的性能评价指标进行了介绍。正确地选用实验关联式及性能指标，将对翅片管式换热器的优化设计及其制造提供可靠的依据。     

中国制冷空调工业协会最新资料

1.中国制冷与空调压缩机现状及发展战略研究(售价:2000元)中国制冷空调工业协会出资委托西安交通大学2005年6月完成的研究项目,包括制冷与空调压缩机行业现状、冰箱压缩机行业现状、家用空调压缩机现状、中央空调压缩机、冷冻冷藏压缩机汽车空调压缩机、制冷空调压缩机的节能与环保、对我国制冷空调压缩机产业发展的一些思考等内容。2、民用住宅户式中央空调与集中空调系统技术经济性论证及分析(售价:2000元)中国制冷空调工业协会出资委托北京建筑工程学院2006年2月完成的研究项目,包括户式中央空调技术经济性分析、集中空调技术经济性分析…     

纯工质水平管内凝结换热研究进展

相对于混合工质,纯工质(单一成分制冷剂)不存在温度滑移、系统泄漏时的成分变化等问题,在制冷设备中得到了广泛应用.研究纯工质水平管内凝结换热特性对其及其混合物在制冷、空调、热泵方面的应用具有重要意义.文章从理论和实验两个方面,综述了国外对纯工质在水平管内流动凝结换热的研究,分析了凝结换热关联式的适用性和局限性,并提出了进一步研究的建议.     

会讯

正2014年11月(具体日期待定),中国制冷空调工业协会将在北京主办"第七届中国制冷空调行业信息大会"。本次会议诚挚邀请行业内外的专家、学者和技术人员撰写文章,围绕国家相关政策法规标准及其目标导向,交流探讨制冷空调行业国内外最新发展动态和趋势,充分展示行业各种节能环保技术、新产品、新市场的开发研究应用成果,全面总结制冷空调行业近年来在技术创新方面所取得的成果,深入分析     

制冷空调装置智能仿真方法研究初探

简要论述了制冷空调装置数值仿真的发展特点及其在实际应用中的局限性，在此基础上提出将现代人工智能技术引入到制冷空调装置仿真研究中。通过概述并分析人工智能技术在制冷空调行业的应用现状，提出基于模型的制冷空调装置智能仿真方法。最后通过压缩机热力性能神经计算的实例演示智能仿真方法的效果。     

多回路制冷空调综合型实验系统的研制

制冷系统是多输入、多输出的系统,而且各操作参数相互关联.随着环境和室内热负荷的变化,制冷空调系统通常是在变工况条件下运行.为全面研究制冷系统的实际工作特性,研制开发了变频蒸气压缩式多回路制冷空调综合性实验系统,通过调节连接蒸发器和冷凝器的空气回路可以在任何时间模拟实现全年的运行工况,而不受季节的影响.详细介绍了实验系统的设计原理、调节方法、技术参数和数据采集系统.利用该实验系统既可获得参数间的动态关联特性,还可进行单体设备的性能测试以及不同控制策略的比较实验,为制冷系统动态仿真研究、各部件的合理匹配和优化运行控制策略提供实验基础.     

微肋管内制冷剂流动沸腾换热研究进展

内微肋管是增强管内凝结与沸腾换热的重要技术之一,在制冷空调领域有着广泛的应用。本文基于对近年文献回顾,从实验和计算关联式两方面综述了微肋管中沸腾换热的研究现状,总结了质量流速、热流密度、干度、管道结构、润滑油等对换热系数和压降的影响,讨论了现有的沸腾换热关联式的适用性和准确性,并指出了需要进一步研究的问题。     

《制冷与空调》2001年稿约

1 《制冷与空调》杂志是由科学技术部主管,中国制冷空调工业协会、中国科技交流中心联合主办的制冷空调行业最具权威的行业综合性刊物。本刊宗旨是加强行业管理,密切政府、行业、企业联系,融信息、技术管理为一体,促进科技成果转化,推动制冷空调行业技术进步与发展。 2 本刊面向制冷空调及相关行业广大职工     

制冷用水平降膜式蒸发器研究进展

降膜式蒸发器目前在牛奶、制药、化工、海水淡化等行业取得了较为广泛的商业应用,它从上世纪90年代以后开始应用于制冷空调系统。目前针对制冷用水平降膜式蒸发器的研究目的主要是明确各个参数对蒸发器传热性能的影响以及他们之间的联系,由于降膜式蒸发器的独特结构和内部传热传质的复杂性,这些研究尚处于初步阶段。在介绍其工作原理的基础上,针对水平降膜式蒸发器,着重讨论了布液器的结构与高度、管束(包括管径、管排数、管道表面形状)、制冷剂(流型、流量)等参数对其性能的影响。由于经验关联式在实际应用中的巨大优势,还总结了前人提出的关联式及其适用的范围,文章将为制冷用降膜式蒸发器的进一步研究和应用提供参考。     

制冷空调维修规范化操作培训教材编写启动会召开

正2013年12月10日,中国制冷空调工业协会组织召开了制冷空调维修规范化操作培训教材编写启动会。来自环境保护部对外合作中心、中国制冷空调行业内的维修企业、生产企业所属的售后维修服务部门及高校的30余位专家代表参加了会议。中国制冷空调工业协会秘书长张朝晖主持会议并致辞:"目前,加速HCFCs淘汰是制冷空调行业面临的最重要的任务之一。为减少维修过程中制冷剂的使用量,受环保部对外合作中心的委托,中国制冷空调工业协会承担了组织编写制冷空调     

制冷空调系统水平管降膜蒸发研究

在制冷剂面临严峻的环境保护控制要求的背景下,研究表明,降膜蒸发由于其较低的制冷剂充注量在制冷空调行业具有重大的应用潜力。本文主要从降膜蒸发管外液膜的流动模式和强化传热2个方面,对水平管降膜蒸发的国内外研究现状进行研究分析。分析表明,管外液膜存在滴状流、射（柱状）流和片状流等模式,而且强化传热须区分高低热流密度情况。为了进一步探究降膜蒸发的机制,从换热和可视化的角度开展强化管外降膜蒸发的特性实验研究。     

几种管外凝结强化管的传热试验及分析

对几种管外凝结强化管及相应的光滑管进行传热试验,介绍试验装置、试验原理和方法,分析冷凝强化管表面的形状和结构参数对强化换热的影响。通过试验及采用Wilson法和分离法得到这几种管子的管外冷凝换热强化效果数据,给出换热强弱对比的有关图表,并分析这几种强化管强化换热的机制。     

Flow condensation heat transfer correlations in horizontal channels

Condensation heat transfer in tubes is extensively used in many industrial sectors. There were a number of investigations evaluating the correlations of condensation heat transfer in tubes. However, either the data used or correlations involved were limited, resulting in inconsistent conclusions. This paper presents a comprehensive review of correlations for flow condensation heat transfer in horizontal channels. A database containing 2563 experimental data points of condensation heat transfer in horizontal channels, including 1462 data points from conventional channels and 1101 from minichannels, is compiled from 26 published papers, with which 28 correlations are evaluated and analyzed. Twelve correlations have the mean absolute deviation (MAD) less than 30% against the database, and eight have 30% ≤ MAD < 40%. The MADs of the best predictions for the entire database, conventional channel data, and microchannel data are 17.0%, 14.4%, and 20.6%, respectively, indicating a need to improve the prediction method for microchannels.     

Condensation inside and outside smooth and enhanced tubes — a review of recent research

Condensation heat transfer, both inside and outside horizontal tubes, plays a key role in refrigeration, air conditioning and heat pump applications. In the recent years the science of condensation heat transfer has been severely challenged by the adoption of substitute working fluids and new enhanced surfaces for heat exchangers. Well-known and widely established semiempirical correlations to predict heat transfer during condensation may show to be quite inaccurate in some new applications, and consequently a renewed effort is now being dedicated to the characterisation of flow conditions and associated predictive procedures for heat transfer and pressure drop of condensing vapours, even in the form of zeotropic mixtures. This paper critically reviews the most recent results appeared in the open literature and pertinent to thermal design of condensers for the air conditioning and refrigeration industry; both in-tube and bundle condensation are considered, related to the use of plain and enhanced surfaces.     

A review of hydrocarbon two-phase heat transfer in compact heat exchangers and enhanced geometries

Hydrocarbons are considered as alternative fluids for refrigeration, air-conditioning and heat pump applications. Pure butane, propane or their mixtures can be adopted, but due to their flammable properties, the systems have to be designed in such a way that the refrigerant charge is minimized. Therefore, compact heat exchangers and enhanced geometries are adopted in such systems. In this paper, the current state of the art for two-phase heat transfer calculations for pure hydrocarbons and their mixtures is reviewed and analysed. Recommendations are proposed for estimating evaporation and condensation heat transfer in various geometries including enhanced tubes as well as compact heat exchangers.     

蒸发器建模仿真与试验的比较

采用稳态分布参数模型对R134a单元机的蒸发器进行仿真。使用改进的Kattan模型对R134a在光滑管内的流动形式进行划分，从而得出流型图。根据流型图，应用不同表达形式的关联式计算管内局部沸腾换热系数。CCWang的模型用于计算百叶窗形翅片管式蒸发器的表面换热系数及压降。析湿系数通过试验数据建立的数据库确定。在仿真过程中，应用隐式三次多项式拟合模型计算R134a的物性。将仿真结果与试验数据对比发现，仿真值能够较为真实的反映机组的运行状态。通过误差分析得出制冷量的平均相对误差为1．12％，出风干球温度的平均相对误差为1．25％，出风焓的最大相对误差为0．88％，R134a出口温度的平均相对误差为4．0％。     

A survey of correlations for heat transfer and pressure drop for evaporation and condensation in plate heat exchangers

Plate Heat Exchangers (PHEs) are used in a wide variety of applications including heating, ventilation, air-conditioning, and refrigeration. PHEs are characterized by compactness, flexible thermal sizing, close approach temperature, and enhanced heat transfer performance. Due to their desirable characteristics, they are increasingly utilized in two-phase flow applications. Detailed research on heat transfer and fluid flow characteristics in these types of exchangers is required to design and use plate heat exchangers in an optimal manner. This paper reviews the available literature on the correlations for heat transfer and pressure drop calculations for two-phase flow in PHEs as an initial process step in order to understand the current research status. Comparative evaluations for some of the existing correlations are presented in the light of their applicability to different refrigerants. Overall, there is a significant gap in the literature regarding two-phase heat transfer and fluid flow characteristics of these types of exchangers.     

Failure analysis of a copper tube in a finned heat exchanger

This paper reports on the failure analysis of a finned heat exchanger which leaked in the pressure test during commissioning. The heat exchanger was composed of panels made of thin-walled copper tubes and aluminum fins, and the structure was typical of equipment used in the heating, ventilation and air-conditioning industry. The tube material was phosphorus deoxidized copper Cu–DHP. In the pressure test, one of the tubes was found to have three leakage points. The investigation showed that the failure was a consequence of ant-nest corrosion, as all the experimental findings, together with the copper grade and the tube dimensions, were typical of this corrosion mechanism. Corrosion had initiated from the outer surface of the tube. The paper presents the morphology of the failure using optical and scanning electron microscope (SEM) micrographs. The presence of a contaminating organic substance on the outer tube surface and inside the corrosion crack was verified by SEM/EDS analyses. The corrosion mechanism and the relevant chemical reactions given in the literature are summarized, and the conditions in which the failure may occur are presented. Ant-nest corrosion is a special form of local corrosion, and associated most often with deoxidized copper tubes used in heat transfer applications as in this study.     

水平双侧强化管传热性能测定的新方法及实验研究

针对水平双侧强化管的传热性能测定提出了一种新的方法,称之为水环实验法,其基本过程是:在自行设计的套管换热装置中,通过实验得到缠绕铜丝的光滑传热管管外环形小通道内单相水传热关联式,应用该式通过热阻分离的方法得到一种新齿形内螺纹双侧强化传热管的管内传热关联式。同时研究了对于该管水在管内对流和制冷工质R123在管外凝结的传热情况,并采用水环实验法和常规热阻分离法对实验数据进行处理。经过实验研究和理论分析表明:本文的方法所得到的管内外传热系数较常规热阻分离法更加准确。