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真空绝热板中的热桥效应及其优化措施 总被引:3,自引:1,他引:2
真空绝热板的芯材具有很低的热导率,但是用于维持真空度的高阻隔表面隔膜造成的热桥会使真空绝热板整体热导率明显提高。本文以国外近几年对热桥的相关研究为基础,总结了热桥的研究方法,热桥的影响因素及降低热桥效应的有效措施,并且指出今后我国在真空绝热板热桥方面的发展方向。 相似文献
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本文介绍了HB-1高阻隔镀铝复合膜材质结构、阻隔性能、复合强度等关键技术问题分析与对策。需要特别强调的是:镀铝聚酯薄膜(VMPET)采用丙烯酸类树脂预先涂覆处理再真空镀铝,使得HB-1高阻隔镀铝复合膜具有显著的技术创新性、性能指标先进性和市场竞争优势。 相似文献
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研究了聚酯PET/聚丙烯PP药品包装用复合膜的高阻隔性能,其氧气透过量最低可达0.7cm3/(m2·24h·0.1MPa),水蒸气透过量最低可达1.0g/(m2·24h),通过不同材料阻隔性能的对比及对复合膜红外分析,得出胶粘剂种类和其致密的粘合层结构,可能是材料拥有高阻隔性能的主要原因。 相似文献
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本介绍了HB—1高阻隔镀铝复合膜的材质结构、工艺路线以及其阻隔性能、复合强度等关键技术指标的影响因素。镀铝聚酯薄膜(VMPET)采用丙烯酸类树脂预先涂覆处理再真空镀铝,解决了铝层容易转移问题,使得镀铝层厚度从常规的320~420A提升到500~550A,且复合强度优良。HB—1高阻隔镀铝复合膜具有显的技术创新、性能指标先进性和竞争性成本优势,因此应用前景广阔。 相似文献
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赵洪凯王宗灿徐岩 《真空科学与技术学报》2023,(9):805-811
为了提高单向切割真空绝热板应用的广泛性,重点在于研究其绝热性能,提出以热桥效应为对象进行研究。文章采用线性传热率这一概念作为评价热桥效应的基准量。运用理论分析的方法、建立数学模型,进行了单向切割真空绝热板热桥效应分析。根据稳态传热边界条件,提出了热流传递模型,对阻隔膜的厚度和VIP的总厚度两个参数进行分析和计算。实验结果表明,芯材的厚度与导热、阻隔膜厚度与导热、VIP的大小与拼接之间的缝隙都会对热桥效应造成影响。其中芯材导热和厚度得到提高,阻隔膜导热和厚度降低,拼接缝内填充介质导热和厚度降低,VIP尺寸增加,热桥效应呈减弱趋势。文章通过对比有无热桥效应的单向切割真空绝热板,其有效导热系数可提升42%,进而实现对单向切割真空绝热板的高效利用率,增加其绝热性能。 相似文献
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The major carrier of liquefied natural gas (LNG) is LNG ships, whose containment system is composed of dual barriers and composite insulation panels. The LNG containment system should have cryogenic reliability and high thermal insulation performance for safe and efficient transportation of LNG. The secondary barrier composed of adhesive bonded aluminum strips should keep tightness for 15 days, when the welded stainless primary barrier fails. However, cracks are generated in the composite insulation panels due to the local stress concentration and the brittleness of insulation materials at the cryogenic temperature of −163 °C. If cracks generated in the insulation panel propagate into the secondary barrier, LNG leakage problem might occur, which is a remaining concern in ship building industries.In this study, crack retardation capability in the composite insulation panel was investigated with glass fabric reinforcement. Finite element analysis was conducted to estimate the thermal stress at the cryogenic temperature and a new experimental method was developed to investigate the failure of secondary barrier of composite insulation panel. From the experimental results, it was found that the glass fabric reinforcement was effective to retard the crack propagation into the aluminum secondary barrier from the polyurethane insulation foam at the cryogenic temperature. 相似文献
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Samuel Brunner 《Vacuum》2008,82(7):700-707
The recently introduced vacuum insulation panel (VIP) is a space saving alternative to conventional thermal insulation, thanks to its five to eight times higher thermal resistivity. As gas permeation through the envelope barrier may drastically reduce the insulation efficiency, aging effects and service life expectation are crucial aspects of those high performance insulation units. In the present paper, monitoring data from a terrace construction over more than 3 years are reported. The results are compared with laboratory aging data at constant conditions by linear and Arrhenius weighting of the dynamic boundary conditions. Based on satisfactory agreement, a similar approach is applied for the prediction of the thermal performance after an installation time of 25 years, the common time used for building design regarding energy performance. 相似文献
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真空镀铝复合膜呈现"局部透明"的技术,依靠的是一种在特定工艺下能使铝层与基膜相互分离的透明涂料(或腊克)。而依据特定工艺使用的材料不同,该技术可分为"水洗铝"和"酸/碱洗铝"两种。然而,经过"局部透明"工序制得的镀铝复合袋,透明区域的铝层被洗除,仅剩基膜和热封膜复合,该部分的阻隔性较其他镀铝区域必然有所下降。倘若内容物对水、氧非常敏感,那么这种阻隔性的变化将会对内容物的品质产生重大影响,进而缩短相应的保质期。 相似文献
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采用磁控溅射工艺制备玻璃基Ag/TiO_2复合膜,研究TiO_2膜的射频功率、溅射时间、氩气流量和本底真空度4个制备参数对复合膜隔热性能的影响。结果表明:复合膜的隔热温差随着射频功率、溅射时间、氩气流量、本底真空度的增加均呈现先增大后减少的变化趋势;4个制备参数对复合膜隔热温差的影响程度由大到小的顺序依次为本底真空度、溅射时间、射频功率、氩气流量;4个制备参数的较优组合为本底真空度4×10~(-3) Pa,射频功率150 W,溅射时间15 min,氩气流量20 m L/min。 相似文献
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Cabrera和Nugroho等人对3v3(3 mm单层玻璃+0.2 mm真空层+3 mm单层玻璃)、3v5以及5v5构造的真空玻璃进行了研究,结果表明真空玻璃的隔声特性符合薄板隔声理论,但10 mm单层玻璃较符合厚板隔声理论。因此需进一步研究当真空玻璃的厚度进一步增大后的隔声特性。文章增加真空玻璃厚度至3v10,采用现场声强测量法进行隔声测量,基于Davy和Sharp隔声理论建立了隔声模拟模型,对实测和模拟特性进行对比分析。结果表明,3v10真空玻璃的隔声特性更符合厚板隔声理论。与3v5真空玻璃相比,3v10真空玻璃的计权修正表观隔声量未明显提高,但有助于降低现场隔声等级隔声最低值与评价量之间的差值。 相似文献
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铝蜂窝夹芯复合结构在航空工业、高速列车及汽车车体中得到越来越多的应用,其隔声性能对车内及机舱噪声有重要影响。建立了碳纤维铝蜂窝夹芯复合结构有限单元模型,用有限单元法计算了结构在声载荷激励下的响应,并计算分析了复合结构的隔声性能,分析了碳纤维复合面板厚度、面板层数、铺设角度、铝蜂窝芯层的厚度、铝蜂窝壁厚对隔声性能的影响。研究结果表明,面板采用碳纤维复合结构时,在小于1 000 Hz的低频段,相同面板厚度的铝蜂窝复合结构隔声性能比全铝合金材料的铝蜂窝夹芯复合结构有所降低,而且在高频段会出现隔声量更低的隔声低谷;相较于铝合金面板,复合结构的面板采用碳纤维复合材料时,能够实现整体结构轻量化也提高复合结构的隔声性能;各层之间按相对90°铺设时复合结构隔声性能最好;随着面板厚度的增加复合结构隔声性能增加,面板层总厚度不变的情况下,单层面板或者过多的层数都会使复合结构隔声性能降低。 相似文献
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Design of the composite sandwich panel of the hot pad for the bonding of large area adhesive films 总被引:1,自引:0,他引:1
A light-weight hot pad system for curing large area adhesive films for the secondary barrier of cryogenic cargo containments of Liquefied Natural Gas (LNG) has been developed with a composite sandwich panel.In order to apply uniform pressure to the adhesive on unlevel insulation panels and to obtain an adequate adhesive thickness, a flexible stainless steel foil heater supported by a butyl rubber air pressure bag has been utilized for the lower part of the hot pad system, and a temperature controller provides reliable curing of the adhesive. To decrease the weight of the hot pad system and mitigate heat loss through the pad, the upper part of the hot pad system has been built with a composite sandwich panel composed of glass fiber epoxy composite face, polystyrene (PS) and polyvinyl chloride (PVC) foam cores with low thermal conductivity.Through finite element analysis and experimentation on hot pad systems, a light-weight hot pad system that is able to cure a 0.3 m by 3.5 m area has been developed with an autoclave cure quality. 相似文献