开孔对加气混凝土砌块热工性能影响的数值分析

为分析开孔对加气混凝土砌块热工性能的影响,采用ANSYS Fluent对一种多排孔蒸压砂加气混凝土砌块进行了传热量数值模拟研究,分析了孔内表面辐射、开孔宽度、砌块材料的导热系数,以及孔内填充保温材料对其当量导热系数的影响。研究结果表明:开孔可以降低加气混凝土砌块的当量导热系数,但由于孔内表面辐射传热和对流换热的影响,开孔对其热工性能的提升效果并不明显,较大的开孔宽度会导致砌块热工性能的下降;导热系数不同的砌块开孔后,其当量导热系数的降低程度随材料导热系数的增大而增大,B03~B08加气混凝土砌块达到其最小当量导热系数的开孔宽度为6~10 mm;多排孔砌块孔内填充保温材料可有效降低其当量导热系数,填充保温材料的导热系数越小,砌块热工性能改善越显著。     

复合自保温砌块导热系数随含水率变化规律

为研究含水率对砌块导热系数的影响,通过吸放湿试验对一种粉煤灰混凝土复合自保温砌块的热工性能进行试验研究,得到该砌块主体材料和填充材料的导热系数随其平衡含湿量的变化规律,并通过数值软件给出变化函数。试验结果显示,主体材料导热系数随平衡含湿量的增加明显呈指数增加趋势,填充材料导热系数随含湿量呈指数增加的趋势并不明显,但其导热系数也随含湿量的增加而增加,该试验为今后进一步研究墙体热工性能提供参考依据。     

不同填充材料对烧结页岩保温砖热工性能的影响

采用有限元分析软件fluent对5种填充不同保温材料的烧结页岩保温砖进行三维导热数值模拟,模拟中考虑了导热、辐射和孔洞内对流换热同时作用的复杂的传热过程,模拟结果表明:保温材料的填充能够明显提高烧结页岩保温砖的热工性能,当填充物为酚醛树脂时,其保温效果最好,且综合考虑造价、耐热性等因素,酚醛树脂是最为理想的填充材料。     

高孔洞率复合保温砌块设计及热工性能影响因素

提出了高孔洞率复合保温砌块孔型的设计方法,同时采用ABAQUS有限元软件进行数值模拟,分析了复合保温砌块的孔型排布、孔洞率和材料导热系数对其热工性能的影响.结果表明:复合保温砌块的热阻随孔洞率的提高而增加,随实体材料导热系数的降低而增加,随填充的保温材料导热系数的降低而增加;通过数值模拟计算,得到了复合保温砌块热阻与孔洞率、实体材料导热系数、保温材料导热系数的关系公式;在灰缝对墙体传热影响很小的情况下,当砌块孔洞率为60%时,240mm厚单一砌块墙体的传热系数能达到0.29W/(m2·K),满足砌块和墙体热工性能大幅提升的需求.     

相变材料导热和阻燃性能研究

相变材料用于建筑领域可以提高能源利用率与居住舒适度，但还需解决导热性能低、易燃的问题。文中在相变材料中掺加膨胀石墨等材料，通过平板导热系数测定仪测定增强导热性能的效果，发现膨胀石墨、铜网和泡沫铜可以显著提高相变材料的导热性能。此外，在相变材料中掺加二类阻燃剂，通过测试闪点温度和热重分析，发现二类阻燃剂均可提高相变材料的阻燃性能，并且在有膨胀石墨协同阻燃时，可以进一步提高阻燃性能。     

导热硅脂

导热硅脂主要用于填充功率元器件和散热器的装配面，帮助消除接触的空气间隙，可增加热流通道，减少电阻，以便降低电子元器件的温度，提高其可靠性和使用寿命，也可用于电脑CPU风扇与散热片之间j的热传导。本产品是用具有良好的导热、绝缘性能的真料与有机硅脂混合而成的白色膏状物，在长时间1200℃，甚至200℃以上的高温露置也不干、不硬、不溶化、且无味、无臭，对铁、铜、     

碳纤维梯度分布对水泥基材料热、电性能的影响

研究了碳纤维梯度分布条件下对水泥基材料导电发热性能及其内部热应力的影响。结果表明,在一定碳纤维含量下,电阻率迅速下降,通电后可快速发热并随着体系温度的升高而发热率下降,最终可达到发热与散热的平衡而使体系温度趋于恒定。碳纤维梯度分布,尤其不发热区碳纤维的存在,改变了体系的导热机制,即由单纯的声子导热变为电子、声子复合导热,提高了水泥基材料的导热性能,有利于内部的热扩散,使材料更快地趋于热平衡,大大节约了碳纤维的用量,并可在完成其导电发热功能的前提下,大大降低发热层与不发热层之间的温度差和温度应力,从而提高材料的使用寿命。     

石墨填充式PV/T系统光电光热性能试验

设计制作了一种以高导热材料——石墨为填充介质的新型PV/T结构,并搭建了该PV/T系统的光电光热性能综合试验台,在大连地区对其光电光热性能进行了试验研究。研究结果表明：在天气晴朗的情况下,与普通PV板相比,石墨填充式PV/T系统的输出功率相对提高可达120.67%;系统的瞬时热效率可达28.68%;系统水经过一天的循环,可使水箱温度上升至38℃。     

异型啮合式轻集料混凝土复合自保温砌块的块型设计及相关性能研究

采用异型啮合式结构,对轻集料混凝土复合自保温砌块的块型结构进行优化设计,以提高其保温隔热性能及整体稳定性;对自保温砌块的空腔填充材料进行了对比筛选。结果表明,采用膨胀玻化微珠砌筑砂浆能显著减小砌体的导热系数。研制的空腔填充XPS板的异型啮合式轻集料混凝土复合自保温砌块的热阻为1.35 m~2·K/W,采用膨胀玻化微珠砂浆砌筑异型啮合式砌块时,砌体的当量导热系数为0.38 W/(m·K),满足外墙节能要求。     

高强度氯化聚乙烯防水卷材的制备及性能研究

以氯化聚乙烯为主要原料研制出了高强度氯化聚乙烯防水卷材,讨论了氯化聚乙烯、增塑剂、填充材料及改性剂对卷材性能的影响。     

ACR/CPVC/石墨粉体共混导热材料的研究

使用丙烯酸酯共聚物（ACR）作为氯化聚氯乙烯（CPVC）的改性剂,使用超微细石墨粉体做填料,制备了具有导热性能的共混材料。实验结果表明,该材料的导热系数可以提高近20倍,维卡耐热温度达到135℃。     

微晶石墨制备各向同性石墨的研究

本文研究了以天然微晶石墨为骨料制备各向同性石墨材料的可能性,对比传统骨料发现,微晶石墨模压制备的样品具有较低的各向异性指数1.11,较高的体积密度1.73g/cm3及良好的力学性能。以微晶石墨做为骨料采用等静压成型时,样品的各向异性指数低于1.05。同时还研究了粒度配比、浸渍工艺、粘结剂含量对材料性能的影响。     

颜填料含量对水性环氧树脂防腐蚀涂料性能的影响

本文根据涂料的防腐蚀机理,探讨以环氧树脂为基料的水性防腐蚀涂料中颜填料含量对涂料性能的影响。本文主要选用磷酸锌作为防锈颜料,根据CPVC/PVC的变化对涂料性能影响的理论,设计配方组成含量。然后通过调整三聚磷酸铝、铁红、硫酸钡颜料用量,观察涂料防腐性能的变化。探讨了三聚磷酸铝、氧化铁红、硫酸钡颜料Fe_2O_3含量对漆膜的性能的影响。     

Investigation of factors affecting the accumulation of vinyl chloride in polyvinyl chloride piping used in drinking water distribution systems

Plastic piping made of polyvinyl chloride (PVC), and chlorinated PVC (CPVC), is being increasingly used for drinking water distribution lines. Given the formulation of the material from vinyl chloride (VC), there has been concern that the VC (a confirmed human carcinogen) can leach from the plastic piping into drinking water. PVC/CPVC pipe reactors in the laboratory and tap samples collected from consumers homes (n = 15) revealed vinyl chloride accumulation in the tens of ng/L range after a few days and hundreds of ng/L after two years. While these levels did not exceed the EPA’s maximum contaminant level (MCL) of 2 μg/L, many readings that simulated stagnation times in homes (overnight) exceeded the MCL-Goal of 0 μg/L. Considerable differences in VC levels were seen across different manufacturers, while aging and biofilm effects were generally small. Preliminary evidence suggests that VC may accumulate not only via chemical leaching from the plastic piping, but also as a disinfection byproduct (DBP) via a chlorine-dependent reaction. This is supported from studies with CPVC pipe reactors where chlorinated reactors accumulated more VC than dechlorinated reactors, copper pipe reactors that accumulated VC in chlorinated reactors and not in dechlorinated reactors, and field samples where VC levels were the same before and after flushing the lines where PVC/CPVC fittings were contributing. Free chlorine residual tests suggest that VC may be formed as a secondary, rather than primary, DBP. Further research and additional studies need to be conducted in order to elucidate reaction mechanisms and tease apart relative contributions of VC accumulation from PVC/CPVC piping and chlorine-dependent reactions.     

水性聚氨酯／水泥／碳黑导电涂层的研究

将水性聚氨酯、导电碳黑和石墨、水泥粉体和其他助剂共混,研制开发了一种复合导电涂层材料。实验结果表明,该涂料的体积电阻率达到10^3Ω·cm,除了具有一定的导电性能以外,也具有良好的机械性能。介绍了材料的配制和性能,讨论了导电填料的含量与涂料导电性能之间的影响及水泥固体粉体含量与涂料机械性能的关系。     

硅灰石和膨润土增强膨胀型钢结构防火涂料

合成具有改善钢结构耐火性能的膨胀型涂料的新配方,涂料配方基于硅灰石和膨润土增强的可膨胀石墨,根据硅灰石和膨润土含量及不同研磨时间配制了十种膨胀型涂料配方。结果表明：随着填料（硅灰石和膨润土）含量和研磨时间增加,炭膨胀率增加,同时能够减少热源向钢板基材的热渗透。X 射线衍射（XRD）分析表明残炭中含有硼酸铝,硼酸铝具有很高的热稳定性,能增强涂料的耐火性能。随着填料含量和研磨时间增加,残炭中碳含量增加、氧含量减少、磷含量增加,较高比例的磷能够有助于增加碳质炭的形成。较高填料含量和研磨时间能够增加残余重量和耐火性能。     

The Impact of Mounting Method on the Flammability Testing of Chlorinated Poly Vinyl Chloride (CPVC) Pipe Type Certification for Maritime Applications

A series of tests was performed to elucidate the impact of the mounting methods on the performance of chlorinated poly vinyl chloride (CPVC) pipe in accordance with International Maritime Organization Fire Test Procedures Annex 1 Part 5. Also assessed, was the determination whether the current practice in type approval for the certification of all CPVC pipe sizes between smallest diameters, thinnest pipe tested and largest diameters, thickest pipe tested is a valid practice. Whole diameter pipe and pipe cut in half longitudinally were tested in the Lateral Ignition and Flame-Spread Test apparatus to determine if the different configurations of the pipe induced variability. A total of 42 tests were performed to look at sizes 12.7-mm copper tube size (CTS) through 38.1-mm Schedule 80 CPVC pipes. The following factors produced statistically different data at the 99% confidence limit: longitudinally half cut, versus whole, of the same pipe size and type, and thickness of the pipe for both total heat release and peak heat release rate (PHRR). Thickness is important with thicker pipe performing better in the testing. Whole pipe of the thinner material, CTS, versus the same pipe produced from longitudinally cut pipe, increased the heat produced significantly by holding the pipe in the combustion zone longer. Thin cut pipe appeared to melt and char, and fall out of the sample holder and the combustion zone, effectively reducing the mass consumed and energy produced. For Schedule 40 pipe of whole smaller pipe diameters, 12.7 mm, performed significantly better for both PHRR and total heat release than the longitudinally cut pipe. For diameters of 19.1 and 38.1-mm Schedule 40, the same trend was noted with the whole pipe performing significantly better. Thicker materials, such as Schedule 80, develop a thick char layer that stayed in place reducing combustion of CPVC.     

建筑给水管道的性能比较

简述了现阶段我国较流行的建筑给水、采暖供热及消防管道,如CPVC、PP-R、PB、钢塑复合管等,并对它们的各种性能作了对比研究,着重介绍了新型塑料管的特性,有助于提高人们对选择合适的新型塑料管道的认识。     

苯丙乳液水泥复合外墙乳胶漆的研制

叙述了苯丙水泥漆的成膜机理、基本配方、配制工艺和性能，讨论了PVC、CPVC对水泥漆贮存性的影响，并对沉淀分层、变稠、胀性现象及助剂作用等问题进行了讨论。     

中国塑料管材的应用现状与发展趋势

重点介绍了新型氯化聚氯乙烯塑料管材的特点与应用现状,以及我国建筑业中塑料管材的应用情况与存在的主要问题,并且对其应用前景与发展方向进行了展望。