共查询到15条相似文献,搜索用时 78 毫秒
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提出了应用基于谐波探测技术的3ω法进行液体导热性能测量的方法。设计了3ω测试系统,测试了不同浓度和不同温度下纳米流体的热导率和热扩散系数,与文献中的测试结果进行了对比。实验中测试的热波信号较好地满足频域内的导热方程,说明采用交流电流加热可使流体的微对流作用得到有效减弱。采用基于多颗粒布朗运动的微对流(MSBW)模型预测了纳米流体的热导率。浓度比较低时TiO2+蒸馏水、Al2 O3+蒸馏水纳米颗粒流体的热导率随温度增加呈线性增大,并且与液体的Prandtl数有关,在测试温度为18~65℃范围内,水的热导率随温度升高以及纳米颗粒的布朗运动所引起周围基液的微对流作用是纳米流体强化传热的两个重要机理。 相似文献
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热导率和热扩散率是天然气水合物资源开采关键性基础热物性数据,采用反应釜内壁衬有氟塑料材料,低过冷度,让水合物在反应釜内逐层生成的合成方法,获得可直接用于导热测试的二氧化碳水合物样品。采用瞬变平面热源法原位测试了温度264.68~282.04 K、压力1.5~3 MPa二氧化碳水合物热导率、热扩散率,并测试了二氧化碳水合物在268.05 K、0.6 MPa左右发生自保护效应过程中热导率、热扩散率,获得了晶态下和自保护效应过程中的二氧化碳水合物热导率、热扩散率变化特性。测试结果将为天然气水合物资源的开发利用提供基础数据和理论依据。 相似文献
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甲烷水合物的研究和开发 总被引:2,自引:0,他引:2
介绍了甲烷水合物的结构、相平衡性质和在自然界的赋存情况,以及为开采甲烷水合物而进行的钻探和深海开发技术,并探讨了开发甲烷水合物中的环境保护问题. 相似文献
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向模拟煤层气(13.11vol% CH4+86.89vol% N2)中添加5.8mol%四氢呋喃(THF)?0.03mol%十二烷基硫酸钠(SDS)促进剂溶液分离提纯煤层气,考察了压力、温度、反应时间对气体消耗量、反应速率、分解气中甲烷浓度、甲烷回收率和甲烷分离因子的影响,采用色谱分析法分别测定了CH4在剩余气相和分解气相中的浓度。结果表明,压力增加,CH4回收率增大,CH4分离因子增大,CH4分离效果越好;温度是影响甲烷分离因子的关键因素,温度降低,氮气和甲烷竞争进入水合物晶体中,导致水合物相中甲烷浓度降低;温度升高有利于提高水合物对甲烷的选择性。甲烷回收效率最高可达98.65%,分离因子最大为14.83。随反应时间增加,分解气中CH4浓度升高。 相似文献
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为了快速制备甲烷水合物以利于天然气水合物法储运,在自行搭建的液相连续撞击流反应器内考察了纯水和纯水+十二烷基硫酸钠(SDS)2种体系中撞击强度、反应器内温度、初始压力对甲烷水合物快速生成的影响.实验结果表明:2种体系内撞击强度的增加可明显加快甲烷水合物的生成,在撞击强度为0.38、反应的前30 min,水合速率达到最大... 相似文献
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A constant applied heat flux method has been used to measure the specific heat and thermal conductivity of large samples of Utah (North-west Asphalt Ridge) tar sands as a function of temperature. Independent measurements of density allowed for the calculation of thermal diffusivity. Constituent analysis of the tar sand samples also permitted the calculation of bitumen and sand specific heats. Specific heat of the bitumen was found to increase with temperature from 1.85 to 3.9 kJ kg?1 K?1 for temperatures between 300 and 480 K. Specific heat of the sand matrix increased only slightly, from 0.85 to 1.0 kJ kg?1 K? for the same range of temperature. Corresponding thermal diffusivities for tar sand were found to decrease with temperature, and had a range of 5 · 10?7–9 · 10?7 m2 s?1 over the measured temperatures. It was concluded that the latent heat of both bitumen and water have a strong influence on the apparent overall specific heat of tar sand. 相似文献
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Rajni Agarwal N. S. Saxena Kanan Bala Sharma S. Thomas M. S. Sreekala 《应用聚合物科学杂志》2003,89(6):1708-1714
Thermal properties, such as thermal conductivity, thermal diffusivity, and specific heat, of treated and untreated oil palm fiber–reinforced PF composites were measured simultaneously at room temperature and normal pressure using the transient plane source (TPS) technique. An increase in thermal conductivity was observed in the fiber‐treated and resin‐treated composites. Surface modifications of fibers by prealkali, potassium permanganate, and peroxide treatments increased the fiber–matrix adhesion by increasing porosity and pore size of the fiber surfaces. The increase in crosslinking enhanced the thermal conductivity of a composite of resin treated with peroxide compared to other composites. Also an attempt was made to explain the temperature dependence of thermal conductivity and thermal diffusivity of amorphous polymer samples using the same technique. It was observed that at the glass‐transition peak of the polymer, thermal conductivity and diffusivity were maximum. Below and above this temperature their values decreased. This has been explained on the basis of predominant scattering processes. An empirical relationship was established for the theoretical prediction of thermal conductivity and diffusivity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1708–1714, 2003 相似文献
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Mike Coulson Eric Dantras Philippe Olivier Nathalie Gleizes Colette Lacabanne 《应用聚合物科学杂志》2019,136(38):47975
Heat transfer properties play an important role in processing of polyetherketoneketone (PEKK)/carbon fiber (CF) composites. Accordingly, thermal conductivity and diffusivity of PEKK, PEKK/glassy carbon (GC), and PEKK/CF composites have been studied. Observed increase in conductivity and diffusivity with carbon filler addition was analyzed using the Maxwell–Eucken model. PEKK/GC composites with low carbon fraction indicated good fitting experimental points of the model, indicating good dispersion of particles. For PEKK/CF composites, the thermal conductivity and diffusivity increase is a reflection of a decrease in porosity. Results as observed from the model points to a homogenous dispersion within the PEKK/CF composites as well. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47975. 相似文献
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试验研究了不同种类(Al2O3、Cu、SiO2)、不同质量分数(0.05%、0.1%、0.15%)及不同粒径(10、30、50 nm)的纳米粒子对CO2水合物热导率的影响。结果表明温度为-5~5℃时,纯CO2水合物热导率为0.553~0.5861 W·m-1·K-1,具有玻璃体的变化特性。分散剂SDBS的加入,可改善CO2水合物-纳米粒子体系的导热性能。在相同的质量分数和粒径下,纳米Cu粒子对CO2水合物热导率的增强作用最好,但综合考虑水合物生成特性和溶液悬浮稳定性,选用纳米Al2O3粒子较合适。Al2O3粒子粒径越小,水合物热导率越大,15 nm比50 nm纳米粒子体系中CO2水合物热导率的增长率平均提高了12.7%。此外,CO2水合物热导率随Al2O3粒子质量分数的增大而增大,质量分数由0.05%增加到0.15%时,水合物热导率的增长率由4.2%提高到8.2%。 相似文献
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在体积10 L的静态反应器中研究了水合物分解动力学,考察了储存温度和水合物量等因素对水合物分解的影响。实验结果表明,水合物在273.15 K以下时存在一种异常的自我保护效应,其在268.05 K时分解速度最慢;而水合物的储运压力与储罐中的水合物量有关,当储罐容积一定时,分解压力随着储罐中水合物量的增加而增加,但水合物的分解百分比随着水合物量的增加而减少;最后提出了在一定压力下储运水合物的方法。以期为水合物法固态储存气体技术的工业化应用提供实验数据和理论依据。 相似文献