共查询到19条相似文献,搜索用时 156 毫秒
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利用建立的溴化锂降膜式发生器实验台对管内有来福线的低肋管进行实验研究。管内有来福线的整体低肋管管内的来福线用来强化管内的换热,管外的肋片用来强化管外溶液的传热传质。在管内换热状况比较差的情况下,用管内有来福线的整体低肋管能提高整个发生器的传热系数。实验中,在热水流量较小以及热水进口温度较低情况下,这种传热管能有效改善降膜式发生器的传热传质。 相似文献
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本文作者研究了溴化理在制冷机中膜式吸收过程,在几个假定基础上,建立了动量、能量、质量传递方程式。根据这些方程,求出溴化锂水溶液在吸收过程中各点的温度、浓度分布及其传热、传质系数,为制冷机设计和实验研究提供了理论分析。 相似文献
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垂直管外溴化锂溶液降膜吸收的传热传质模型研究 总被引:4,自引:0,他引:4
通过对溴化锂吸收式制冷机中垂直管外降膜吸收过程特点的分析,建立了吸收过程中传热传质相互耦合的数学物理模型,并在此基础上,进一步提出了溶液多次布液降膜吸收的模型;并对吸收过程中液膜流动、传热传质进行了分析,得出的结论可以为吸收器的设计和实际运行的优化提供一定的理论指导。 相似文献
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Yoon Jo Kim Yogendra K. Joshi Andrei G. Fedorov 《Journal of Mechanical Science and Technology》2008,22(2):338-349
Theoretical analysis and simulation of performance of an air-cooled microchannel absorber is reported in this study. It is
shown that the air-cooled microchannel absorber can be integrated into an absorption-based miniature electronics cooling system
by which the chip junction temperature can be maintained near room temperature, while removing 100 W of heat load. Water/LiBr
pair is used as the working fluid and refrigerant vapor is intended to counter-currently flow against aqueous LiBr solution
flow. Parametric study is carried out to determine the effects of several operating parameters, including inlet temperature
and mass flow rate of the coolant, and inlet temperature of LiBr solution. To facilitate the air-cooling of microchannel absorber,
an offset-strip-fin array is adopted, by which enhanced air-side heat transfer coefficient and large heat transfer area are
obtained. The performance of the air-cooled absorber is compared to liquid-cooled absorber. 相似文献
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采用SEM扫描电镜、光谱分析仪、X射线能谱分析仪、机械性能测试机及壁温分析等手段,从化学成分、金相组织、力学性能、介质腐蚀性和壁温等方面,对中国海洋石油国外某气田的海水冷却器UNS$31803换热管腐蚀穿孔机理进行了研究和分析。结果表明,UNSS31803管材产生局部腐蚀穿孔的主因是材料的化学成分缺少氮元素,引起两相比例失调以及管壁温度高于材料临界点蚀温度,使得材料整体耐蚀性能下降。另外,海水中的Zn2+等金属离子与OH一离子反应生成Zn(OH)。沉积在换热管内表面,抑制了材料表层钝化膜的形成,海水中的Cl-离子穿透换热管内表面的Fe(OH)2或Fe2O3·H2O保护层,与Fe^2+不断反应生成FeC{2,以及吸附于腐蚀区域的S2-同母材中的Fe2+反应生成FeS等腐蚀物。此外,在固溶退火过程中,碳化物沿晶界处析出,使得管材产生贫铬现象,进一步加剧了这种腐蚀倾向,其综合作用的结果导致管材腐蚀穿孔。在海水环境卞,使用UNS S31803材料,文中建议将金属壁温控制在30℃范围内。 相似文献
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Cho Yunho Han Sangmoo Seo Hojin Shin Myungseung Woo Sungmin Jeong Siyoung 《Journal of Mechanical Science and Technology》2019,33(6):2995-3000
Journal of Mechanical Science and Technology - Lithium bromide (LiBr)-H2O triple-effect absorption chillers are supposed to have a much higher carbon steel corrosion rate under high temperature... 相似文献
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为了解决工业中的大量低品质烟气余热的回收利用和烟气酸露点腐蚀导致设备容易失效的工程问题,提出了一种复合中空热管传热元件,介绍了其结构及工作原理;对其内部传热机理进行了分析,并对其启动特性、等温性能和传热性能进行了试验研究。研究结果表明:复合中空热管在外管壁温度30℃时,加热时间2 min之内就能正常快速启动工作;在自然空气对流冷却条件下,具有较好的等温特性;复合中空热管的传热系数随着冷却水雷诺数的增加而增加;在加热蒸汽温度低于125℃的低温蒸汽加热条件下,当冷却水的雷诺数为6650时,复合中空热管的传热系数为1350W/(m2.℃)。试验研究结果为复合中空热管换热器的工程应用提供了基础。 相似文献
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Yoo Juhyun Han Sangmoo Nam Youngkwang Jeong Siyoung 《Journal of Mechanical Science and Technology》2020,34(10):4037-4041
Journal of Mechanical Science and Technology - In absorption chillers using LiBr aqueous solution, corrosion problems of carbon steel heat exchangers become more serious as the temperature of the... 相似文献
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Jung-In Yoon Oh-Kyung Kwon Choon-Geun Moon Takao Kashiwagi 《Journal of Mechanical Science and Technology》1999,13(3):264-272
This study investigates the effect of additives such as normal octyl alcohol into lithium bromide-water (LiBr/H2O) solutions in the absorption and generation processes of absorption refrigerating machines. The experimental results confirmed
the positive effect of additive use in the absorber. Little is known, however, on the effect of additives on generator performance.
In this study, the authors carried out experiments to investigate the possible positive or negative effects of additive, which
enhances the absorption process, on the generator behavior. The results showed heat transfer at the generator improved as
pressure increased and concentration decreased; the boiling heat transfer coefficient was shown to be more strongly influenced
by concentration than by pressure. The boiling curves showed that the heat transfer of solution in the generator was not significantly
affected by the addition of surfactant. The result of this study showed that the surfactant in absorption heater/chiller made
enhanced absorption effect in the absorber but it didn't give any influence in the generator. Therefore the additive was devoted
to helping high performance in the absorption system. 相似文献