Experimental study on convection heat transfer of R134a at supercritical pressures in a vertical tube for upward and downward flows
Experimental study on convection heat transfer of R134a at supercritical pressures in a vertical tube for upward and downward flows
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超临界压力下R134a在垂直管内向上和向下流动的对流换热实验研究
DOI：
10.1016/j.applthermaleng.2017.10.120
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发表时间：
2018-01
影响因子：
6.4
通讯作者：
HX Wang
中科院分区：
文献类型：
--
作者：
YL Cui;HX Wang
为了进行有机跨临界循环系统超临界加热器的设计和技术经济评价，对R134a的对流换热进行了实验研究。向上和向下流动的测量范围分别为：质量通量500~1500 kg·m−2·S−1，热通量20~100 kW·m−2，入口压力4.3~4.8 Mpa。讨论了热流密度、压力、浮力和径向物性变化对换热的影响。选择了三个无量纲浮力参数，并与实验数据进行了比较，发现BU值最合适。得到了浮力的阈值。评价了6个具有代表性的关联式，并用实验数据对R134a超临界压力换热系数的新关联式进行了拟合。
For the purpose of design and tech-economic evaluation of the supercritical heater in an organic trans-critical cycle system, R134a’s convection heat transfer was experimentally investigated using a 3 m long vertical smooth stainless steel tube with an 8 mm inner diameter. Measurements were taken for both upward and downward flows in the range of 500–1500 kg·m−2·s−1for mass flux, 20–100 kW·m−2for heat flux, and 4.3–4.8 MPa for inlet pressure. The influence of heat flux, pressure, buoyancy force and radial property variations on heat transfer were discussed. Three non-dimensional parameters for buoyancy were chosen and compared with the experimental data,Buwas found to be the most suitable. The threshold value ofBufor buoyancy was obtained. Six representative correlations were assessed, and new correlations for R134a’s supercritical pressure heat transfer coefficients were fitted with the experimental data.
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影响因子：
2.6
作者：
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通讯作者：
J. Jackson;Mark Cotton;B. Axcell
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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DOI：
10.1016/0017-9310(72)90148-2
发表时间：
1972-01-01
影响因子：
5.2
作者：
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通讯作者：
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