共查询到18条相似文献,搜索用时 432 毫秒
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Dynamic crystallization characteristics of the working process of small type ice slurry maker 下载免费PDF全文
动态冰蓄冷是储能领域中广受制冷界重视的潜热储冷技术,基于平板刮削方式设计并搭建了小型动态制备冰浆实验装置,通过测试制冰溶液的动态结晶降温曲线、不同结晶时刻的含冰率和冰晶当量直径,分析了结晶时间、载冷剂温度、添加剂种类与浓度、刮削速度等因素对冰浆制备过程动态结晶特性的影响。结果表明:刮削速度低于200 r/min,溶液结晶过冷度随刮削速度的增大而增大,冰浆的含冰率以及冰晶粒径均随结晶时间的增加而增大,在冰晶粒径较大时刮削作用引起冰晶颗粒聚并、破碎,导致冰晶粒径增大减缓甚至减小;随添加剂浓度的增大,冰浆含冰率增大速率与冰晶粒径增大量均有所减小,且强极性无机化合物对冰晶生长的抑制效果好于乙二醇等醇类化合物。 相似文献
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钛合金作为一种性能优良的合金被广泛应该用于航空航天领域,经过半个世纪的发展,钛合金的制备工艺有了明显提升,其中真空自耗熔炼技术是目前制备钛合金的主要熔炼技术。论述了真空自耗技术的主要研究现状,较为系统地介绍了改善真空自耗电弧熔炼技术的研究方法及手段,提出了未来真空自耗电弧熔炼控制技术的发展方向。 相似文献
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制取流体冰新方法及高效冰蓄冷研究 总被引:11,自引:0,他引:11
冰蓄冷空调能够有效地将日间部分高峰用电负荷转移到夜间低谷时段,是我国当前积极推广和鼓励的一项重要“削峰填谷”措施。制取块冰、壳冰存在的共同问题是:当冰在固体制冷面形成后,因冰的导热系数很小,将造成很大的传热热阻,并且随冰层厚度的增加而急剧增大,因此制冰能耗高。流体冰(或称为冰浆,Ice Slurry)由于制冰过程中在固体传热面上无冰层产生,实现流动换热,因此制冰过程传热温差小,制取流体冰的热力性能系数可比制取块冰提高近一倍。但现有流体冰制取方法用于冰蓄冷还存有问题,为克服所存在的不足和使制取流体冰的方法更为简单、高效,文中提出了一种制取流体冰的新方法.采用水与非相溶液体接触换热结冰来取代以往水与固体壁面换热结冰,通过将水雾化成细小水滴而大大增加水结冰过程的传热面积,有效地减小了冰层热阻。该种新型制冰方法可使冰蓄冷措施更为经济有效。 相似文献
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针对果蔬预冷设备应用场合,提出并设计了一套以冰浆作为载冷介质的湿冷热湿交换器,并搭建单体性能测试台架,以出风温度和相对湿度为指标,通过改变填料类型(金属、纸质填料)、载冷介质种类(冰浆、冷水)和喷淋流量进行了性能实验研究。结果表明:实验工况下,金属填料的换热性能较纸质填料好;以冰浆作为载冷介质相比以冷水的情况,可以获得更低的出风温度,但出风相对湿度也有所降低;随着进风干球温度的降低,出风温度明显降低,而出风相对湿度变化并不明显;在一定范围内,提高载冷介质的喷淋流量,有利于湿冷热湿交换器出风温度的降低和出风相对湿度的升高;低浓度的冰浆可以在湿冷热湿交换器中稳定运行,且降温效果较冷水湿冷热湿交换器更加明显,虽然相对湿度略有下降但仍然可保持在90%左右,适用于果蔬预冷和保鲜。 相似文献
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为研究直流电压下大吨位绝缘子双串并联覆冰闪络特性,针对CA 785EX绝缘子进行不同串间距下的电场仿真分析,并开展不同污秽度下单I串和双串并联人工覆冰闪络试验。通过分析高速摄影仪拍摄的电弧发展过程,揭示覆冰条件下串间距对双串并联绝缘子冰闪过程、冰闪电压及泄漏电流的影响。结果表明,双串并联时电场会发生不同程度畸变,冰闪过程中电弧发展和泄漏电流呈一定规律性;不同污秽条件下,串间距的影响程度不同;当串间距≥600 mm时,串间距对双串并联绝缘子冰闪电压的影响不显著。研究成果为绝缘子选型配置提供了理论支撑。 相似文献
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This study is purposed to conduct experimental investigation into the characteristics of vacuum flash evaporation with nanofluid under adsorption conditions, with the effects of nanoparticle concentration, surfactant concentration, and nanofluid stability taken into consideration. By measuring absorbency, solute concentration, and sedimentation graph, a new nanofluid with excellent dispersion was developed for the vacuum ice-making system. It has been demonstrated that the low concentration of additive is conductive to not only the maintenance of vacuum but also the generation of binary ice. For nanofluid, there are two distinct freezing stages in the process of vacuum flash evaporation. The supercooling stage of nanofluid is delayed with the increase of surfactant concentration, whereas the TiO2 nanofluid applied to the vacuum ice-making system under adsorption shows stability. Moreover, it is indicated that, for the vacuum ice-making system with TiO2 nanofluid, the pH level is around 8.5, the surfactant is sodium dodecyl benzene sulfonate-span 60 (SDBS-SPAN), the ratio of SDBS to SPAN is about 10:7, the concentration of TiO2 nanoparticle is around 0.20 wt%, and the ratio of TiO2 nanoparticle to SDBS-SPAN is about 10:5. Compared with pure water, undercooling is reduced by 77.92%; the ice packing factor and thermal conductivity are increased by 40.61% and 67.27%, respectively. The results of test and analysis can be applied to conduct further research on vacuum flash evaporation. 相似文献
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根据当地气象资料,模拟计算出在冬天采用柱形冰堆蓄冷的蓄冷效率与柱形冰堆半径之间的关系,予以实际应用可得到很好的经济效益和社会效益。 相似文献
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Dogan Erdemir 《国际能源研究杂志》2019,43(9):4554-4568
Ice thermal energy storage (ITES) is a significant option for shifting cooling load from peak hours to off‐peak hours in order to reduce the cooling cost and equipment capacity. Encapsulated ITES system is one of the most preferred types of ITES systems, because it is easier to apply and has lower initial cost than other types of ITES systems. Capsule geometries have great impact on the thermal performance of the encapsulated ITES system. Spherical capsules are widely used in the application because they provide better thermal performance due to the ratio of its volume to its surface area. Also, modified capsule geometries are used for increasing the thermal performance of the ITES system. This paper focuses on a numerical study in order to determine the effect of the geometrically modified spherical capsule on the thermal performance during the discharging period. Seven geometrically modified spherical capsules were investigated and compared with the ordinary spherical capsule. The FLUENT 17.1 code was used for numerical analyses. At the end of the study, it was found that geometrically modified capsules provided higher thermal performance than an ordinary spherical capsule in the equal capsule volume. Capsule D provided the longest discharging period of 2118 seconds, when VHTF, in = 0.001 m/s and THTF,in = 275.5 K. The lowest discharging time of 464 seconds was obtained with Capsule A, when VHTF, in = 0.01 m/s and THTF, in = 283 K. Among the studied modified capsules, Capsule F performed the worst thermal performance. Energy efficiency values were high, and they did not give comparable difference between the capsule models and working conditions. While all exergy values were 98.50% and higher, exergy efficiency values changed between 85.12% and 51.91%. Exergetically, Capsule D provided the best thermal performance during the discharging period. 相似文献
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高性能过冷水连续制冰系统 总被引:5,自引:0,他引:5
过冷水连续制冰是最近发展起来的一种新的制冰技术,与传统的静态制冰相比,具有较高的制冰率和能量效率,制出的泥状冰分散性好,可以直接随水在管道中输送,在前文研究的基础上,建立了具有较高性能的过冷水连续制冰系统,过冷却器换热段长度3m,过冷却器进口水温为0.5℃,出口水温达到-3.3℃,系统性能可望进一步提高,达到实际开发利用的水平。 相似文献
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减压深拔技术在常减压装置中的应用 总被引:2,自引:0,他引:2
为解决减压渣油后路问题,九江分公司实行减压深拔技术。减压装置拔出率主要受减压塔进料段的油气分压与温度、减压塔内的结焦、进料段雾沫夹带量的影响。减压炉炉管采用逐级扩径的设计.采取转油线本身也吸收部分热胀量的方案,使用1.0MPa蒸汽抽空器,减压塔采用槽式液体分布器及规整填料技术,减四线油南泵抽出后送入减压炉入口循环.操作时,保持塔顶高真空度,提高闪蒸段温度,减压炉炉管适当注汽,减压塔底渣油温度控制在359—362℃.洗涤油流量控制在55~60t/h。实行减压深拨后,装置能耗无大幅变化.产生经济效益达1111.78万元。 相似文献
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阐述了几种常见镀膜工艺的特点,进行工艺比较,结合当前的实际应用对镀膜的应用做了.一定的归纳和总结,对未来镀膜工艺进行展望。 相似文献
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分析了内融式冰盘管融冰放冷过程的动态特性,建立了相应的数理模型,并利用该模型分析了一放冷过程的性能变化,该模型可为冰盘管冷系统的设计和优化提供理论依据。 相似文献