空调制冷铜管“铜铝渗蚀”开裂失效分析

空调换热器制冷铜管在安装数月后出现开裂泄漏制冷剂现象。对开裂的管材进行化学成分、力学性能、断口及金相检验分析。结果表明,Al-Cu渗蚀导致铜管底壁变薄,装配、运转应力导致开裂。追踪生产过程,发现火焰自动钎焊工艺中存在的Al-Cu渗蚀现象为铜管底壁变薄主要原因,据此提出相应的有效解决方案。     

空调制冷铜管的蚁巢腐蚀(下)

(5) 木材和人造建材[5、9、13] 据1999年报道,在一家酒店的木墙房间中用了2.5年的空调发现蚁巢腐蚀,腐蚀从铜管外表面起始.对房间的空气取样做气相色谱分析,发现了有从木材和人造建材中挥发出的挥发性有机物,如甲醛(在空气中的含量达11～13 μg/m3)、壬醇、甲基丁酮、α-蒎烯、柠檬油精和C14-C26烃类化合物.其中的醛和酮引起铜管蚁巢腐蚀的可能性最大.研究者为此专门用9种醛、6种酮和α-蒎烯、蚁酸和甲酸甲酯等17种挥发性物质的潮湿气氛中做了铜管腐蚀试验,发现蚁酸、甲酸甲酯、甲醛、丙醛等会使铜管产生蚁巢腐蚀,而丙酮和α-蒎烯也产生细小的蚁巢腐蚀.萜烯类物质(3-蒈烯、α-蒎烯)都是从木材中散发出来的挥发性物质,而甲醛则是人造建材的胶粘剂中散发出来的.用17种有机物的1%(V.)水溶液进行铜管3个月暴露试验,3个月后各水溶液的PH值如表6,造成铜管蚁巢腐蚀的深度和形貌特征如表7.     

空调制冷铜管的蚁巢腐蚀(上)

空调制新华通讯社铜管的一咱特殊腐蚀一蚁巢腐蚀,易造成空调制冷装置的提前失效.本文综述了空调制新华通讯社铜管蚁巢腐蚀的特征、引发腐蚀的物质、影响因素、试验方法、机理和预防措施.     

空调器室外机热交换器铜管失效分析

某商用空调器室外机安装使用1年后,经清洁公司清理其水垢后发现铜管内冷却水泄露.经查,为室外机热交换器铜管发生穿孔.对铜管使用环境和铜管材质进行化学分析,对该穿孔部位进行了能谱分析,对穿孔处横截面金相分析.结论显示铜管失效为硬水(碱性)条件下的孔蚀,清理中带入的腐蚀性元素加速了铜管失效的速度.     

空调制冷铜管使用中的若干问题

空调铜管是制冷装置的重要原材料 ,它主要有两个用途 :①制造换热设备最常用的蒸发器、冷凝器 ,俗称“两器” ;②作为连接管道和管件。不管那种用途 ,它都是制冷剂的通道 ,其作用十分重要。这就要求铜管生产企业提供优质的铜管 ,另一方面要求空调制冷企业妥善地使用铜管。GB/T1 7791-1 999《空调制冷用无缝铜管》和YS/T440 -2 0 0 1《内螺纹铜管》对铜管的质量作了详细的规定 ,这些规定与美国的ASTMB2 80和日本的JISH3 3 0 0是对应的。本文是从使用铜管的角度 ,既讨论GB和YS中的主要问题 ,也讨论在GB和YS中没有规定的有关问题。1…     

某空调机组换热铜管腐蚀穿孔原因分析

为了研究某空调机组换热铜管发生腐蚀穿孔泄漏的原因,采用宏观检查、化学成分分析、扫描电子显微镜检查及腐蚀产物能谱分析等方法进行分析与讨论。结果表明,腐蚀最主要原因是管内残留物质的存在,使得管壁上形成原电池反应,导致腐蚀穿孔。最后给出防止腐蚀的建议。     

汽车空调用3003铝管穿孔失效分析

为了研究分析汽车空调用3003铝管穿孔失效的原因,采用宏观形貌分析、化学成分分析、扫描电镜微观形貌分析以及能谱分析方法对3003铝管表面孔洞缺陷进行研究。结果表明：3003铝管表面存在的非金属夹杂破坏了铝管表面的完整性和连续性,使得夹杂处不能形成致密的氧化膜,在强腐蚀性元素Cl和S的共同作用下,导致3003铝管出现点蚀穿孔失效。建议在3003合金熔炼过程中控制精炼剂的加入量,并增强铝液中夹杂的过滤效果,同时改善铝管表面清洁度和仓储环境。本研究成果可为3003铝管的制造提供一定的参考。     

微量元素的添加对空调制冷用铜管耐蚀性的影响

分析空调与制冷系统中铜管发生蚁穴腐蚀的机制和原因,研究在典型蚁穴腐蚀易发生的甲酸氛围中微量元素的添加对空调制冷用铜管耐蚀性的影响。结果表明：在纯铜中添加微量元素可以提高制冷铜管耐蚁穴腐蚀的能力,Mn氧化物膜层对提高制冷用铜管的耐蚁穴腐蚀性能发挥了积极的作用。     

铜管蚁巢腐蚀机制及其预防措施

空调换热器用铜管发生的蚁巢腐蚀会导致系统产生泄漏,使制冷、制热性能下降。本文通过介绍蚁巢腐蚀形成的机理,对可能引起蚁巢腐蚀的物质进行相关试验验证,有针对性地提出预防措施。     

乙二醇载冷剂对制冷设备换热器铜管腐蚀分析

为了改善乙二醇载冷剂对制冷设备换热器铜管腐蚀问题,确认腐蚀机理并制定改善措施.通过对铜管腐蚀泄漏点进行宏、微观检查、化学成分分析及扫描电子显微镜检查等方法进行分析讨论.确认铜管腐蚀最主要的原因是制冷系统中的碳钢材料与酸化的乙二醇溶液反应,产生铁离子与换热器的铜管发生电化学反应,导致腐蚀穿孔泄漏.通过对制冷系统的乙二醇腐...     

Analysis of pitting corrosion failure of copper tubes in an apartment fire sprinkler system

Microscopical and structural analyses as well as visual inspection of copper tubes were used to investigate the cause of pitting corrosion failure of copper tubes in the wet pipe sprinkler system. Chemical analysis of the water in the copper tubing and XRF/XRD analysis of its sediments were also used to obtain hints on what was happening in the copper tubing during the progress of the pitting corrosion. It was found from the failed copper tube that a significant amount of pressurized air was present over the water in the copper tubing during operation and a series of corrosion pits were aligned adjacent to the water/air line. The waterline localized corrosion, a type of differential oxygen concentration cell corrosion, induced by pressurized air over the water in the copper tubing was identified as the cause of the pitting corrosion failure. A state of a very low oxygen concentration was maintained under the envelope of a dense layer of malachite, the corrosion byproduct, which was evidenced by the formation of Cu₂O crystalline particles inside the corrosion pit. CuO particles observed on the inside surface of the copper tube do not seem to help prevent local as well as general corrosion. Accelerated pitting corrosion of the copper tube in the wet fire sprinkler system was simulated using a differential aeration cell. Finally, measures for stopping or delaying the pitting corrosion of the copper tube in the wet sprinkler system are suggested.     

某多功能厅空调系统送风方式选择与可行性分析

介绍了浦东图书馆多功能厅工程概况,空调系统送风方式确定的依据,并对夏季与冬季的运行工况分别进行了可行性分析计算,确认所选送风方式的可靠性与舒适性。     

Solar absorption system for air conditioning

This Paper presents a new continous operating solar desiccant absorption system in which CaCl₂-H₂O is used as the absorbent. The flat-plate solar collector is utilized as the desorber where water from the solution is evaporated to ambient air in passing over the collector above the solution film. The plant is equipped with a latent heat accumulation system which is extremely compact in size and very efficient. The coefficient of performance—solar collector efficiency product, indicating the grade of solar energy utilized, is estimated as being the highest of all presently known systems.     

变流量空调水系统稳定性的分析及试验研究

为了探讨压差控制的稳定性,提高该控制方式的节能效果,通过水力稳定度的计算,阐述了水力稳定度对水系统稳定性关系,并讨论了变流量空调水系统中压差设定值及定压点位置对各水力稳定度的影响.最后得出结论:定压点越靠近循环泵,系统总体稳定性越好,但这却降低了水泵的节能效果,压差设定值大小对水力稳定度没有影响.     

Performance analysis of SiO2/PAG nanolubricant in automotive air conditioning system

The performance of an automotive air conditioning system (AAC) needs to be enhanced in order to minimize its environment impact and reduce global fuel consumption. Implementing nanofluid technology using nanolubricants inside compressors can improve its performance. Therefore, this paper presents the development of an AAC system performance test rig. The SiO₂/PAG nanolubricant was prepared in a prior performance experiment and the stability of the colloidal was also attained. The experiment was conducted with initial refrigerant charge ranging from 95 to 125 gram and compressor speeds of 900 to 2100 RPM. The performance of the AAC system was evaluated by determining the heat absorb, compressor work and coefficient of performance (COP). The results found that the maximum increase and the average COP enhancement for SiO₂/PAG nanolubricants are 24% and 10.5%, respectively. It can be concluded that the COP was highest at 0.05% volume concentration for all compressor speeds.     

Aircraft engine bleed system tubes: Material and failure mode analysis

The failures of T-ducts made of Ti A40 with 50 mm in diameter and 0.52 mm in thickness, used in the pneumatic system of a commercial aircraft, are examined as part of a research program aimed to improve the development of such systems. The investigation included the fractographic analysis of the burst parts, microstructure and internal duct surface observations and mechanical tests performed in samples taken from the failed ducts and from unused material. The failed duct fracture surfaces showed typical features of transgranular fatigue cracking. Delamination and oxide particle deposits were found in their internal surfaces. Tensile and fatigue tests revealed some effects of aging, but with no evidence of embrittlement. The fracture mechanisms were the same for the failed ducts and for the unused material. The internal surface damage, associated to the geometry of the duct and to the solid-solution hardening increases the local stress concentration. These facts suggest that cracks had initiated at multiple sites around the inside surface, so that further increments of cracking occurred on subsequent cyclic pressurization during service life until the occurrence of sudden final fast fracture.     

惠安广电数码空调系统设计解析

通过对惠安县广播电视大楼的空调系统设计解析,阐述了对于特殊建筑空调系统的设计和施工原则,由于建筑的结构形式不同、用途功能不同,造成对空调系统的要求随之变化的过程。对于这类建筑的特殊功能和工作环境的特殊性,结合各项经济技术指标等诸多因素,根据各种空调系统运行环境、特点、要求等方面的选择与比较,最终采用了数码涡旋中央空调。本文着重分析了结合建筑特殊功能的合理设计、选用合适的空调系统、因地制宜地布置室内外机、合理系统分区、室内气流组织设计、新风处理方式等方面的内容。将数码空调系统与此类特殊建筑紧密联系在一起,既保证了建筑功能的完整性,又将数码空调系统潜在优势表现得淋漓尽致,为今后同类建筑进行空调系统设计提供了可借鉴的经验。     

蓄能空调系统中蓄能槽体的设计选型及经济性分析

阐述了蓄能空调系统中的蓄能槽体的分类和性能以及方形钢板蓄能槽体的设计选型,介绍了工程实践中常用的圆形槽体和方形槽体的容积与重量关系的统计资料,可供蓄能设备的选型设计及估算重量作参考.     

Analysis of an air cycle refrigerator driving air conditioning system integrated desiccant system

This study presents theoretical investigation on the performance of air cycle refrigerator driving air conditioning system integrated desiccant system. Total system performance is evaluated and the system feasibility is examined. The system has such characteristics that (1) safe material of air and water are used as a refrigerant, (2) waste heat from air cycle refrigerator performs the regeneration of desiccant material for energy saving. It has been clarifying that (1) controlling the evaporative cooling process in air washer, the system can operate for a wide range of cooling loads, (2) the total coefficient of performance on air conditioning system is better than the conventional vapor compression system with reheating coil, and (3) the system performance highly depends on the ratio of the amount of outdoor intake air to the supply air.     

基于空气焓值的变风量空调冷量计量

根据变风量空调系统的运行特点,以空气焓值为依据,通过新风、送风和回风的焓值来计算用户的冷量消耗进而解决变风量中央空调的准确分户计量.该文在准确性和公平性的前提下,为满足实际工程经济性的要求,给出焓值测量的不同方案.计量理论明确,可操作性强,为变风量空调系统分户计量提供一种合理的方法.