Systematic heat transfer measurements in highly viscous binary fluids
Systematic heat transfer measurements in highly viscous binary fluids
复制标题
高粘度二元流体的系统传热测量
DOI：
10.1007/s00231-021-03087-w
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发表时间：
2021
影响因子：
2.2
通讯作者：
M. Richter
中科院分区：
文献类型：
--
作者：
A. Fleer;R. Span;M. Richter
对高粘度流体流动沸腾的研究表明，这种流体的换热机理不同于制冷剂或水等低粘度流体。为了更好地了解，开发了一种改进的标准仪器；它是专门为高粘度流体设计的，最高可达1000Pa∙S，可以使用单个水平试管测量大范围热通量的换热。在这里，我们测量了三种不同聚二甲基硅氧烷(PDMS)和正戊烷(混合物中的挥发性成分)在池沸腾条件下的传热系数。对混合工质的池式沸腾进行了系统的实验研究，重点考察了温度、非挥发性组分的粘度和挥发性组分的比例对换热系数的影响。此外，还利用抛光和砂光表面的铜质试管研究了表面结构对换热系数的影响。结果表明，在高粘混合物中，混合物的粘度和组成对换热系数的影响最大，即混合物的粘度取决于所用PDMS的基粘度、混合物中正戊烷的浓度和温度。对于核态沸腾，试管表面结构的影响没有在低粘度纯流体沸腾实验中观察到的明显，但换热系数的相对提高仍然是显著的。特别是对于挥发性组分浓度较高的混合物，在较高的池温下，换热系数随着热流密度的增加而增加，直到达到最大值。当热流密度进一步增大时，换热系数再次降低。受热面与熔池的温差比低粘度沸腾流体的温差大得多。在13.6kW/m2的热流密度下，测量了高达137 kK的温差(对于质量分数为5%的正戊烷的混合物)。
Investigations of flow boiling in highly viscous fluids show that heat transfer mechanisms in such fluids are different from those in fluids of low viscosity like refrigerants or water. To gain a better understanding, a modified standard apparatus was developed; it was specifically designed for fluids of high viscosity up to 1000 Pa∙s and enables heat transfer measurements with a single horizontal test tube over a wide range of heat fluxes. Here, we present measurements of the heat transfer coefficient at pool boiling conditions in highly viscous binary mixtures of three different polydimethylsiloxanes (PDMS) andn-pentane, which is the volatile component in the mixture. Systematic measurements were carried out to investigate pool boiling in mixtures with a focus on the temperature, the viscosity of the non-volatile component and the fraction of the volatile component on the heat transfer coefficient. Furthermore, copper test tubes with polished and sanded surfaces were used to evaluate the influence of the surface structure on the heat transfer coefficient. The results show that viscosity and composition of the mixture have the strongest effect on the heat transfer coefficient in highly viscous mixtures, whereby the viscosity of the mixture depends on the base viscosity of the used PDMS, on the concentration ofn-pentane in the mixture, and on the temperature. For nucleate boiling, the influence of the surface structure of the test tube is less pronounced than observed in boiling experiments with pure fluids of low viscosity, but the relative enhancement of the heat transfer coefficient is still significant. In particular for mixtures with high concentrations of the volatile component and at high pool temperature, heat transfer coefficients increase with heat flux until they reach a maximum. At further increased heat fluxes the heat transfer coefficients decrease again. Observed temperature differences between heating surface and pool are much larger than for boiling fluids with low viscosity. Temperature differences up to 137 K (for a mixture containing 5%n-pentane by mass at a heat flux of 13.6 kW/m2) were measured.
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DOI：
10.1016/j.ijheatmasstransfer.2018.12.176
发表时间：
2019-04
影响因子：
5.2
作者：
L. Chien;Yue-Lin Tsai;Ching-Hung Chang
通讯作者：
L. Chien;Yue-Lin Tsai;Ching-Hung Chang
开发用于高粘性二元流体传热测量的改进标准装置
影响因子：
2.2
作者：
Ann;M. Richter;R. Span
通讯作者：
R. Span
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DOI：
--
发表时间：
1982
期刊：
影响因子：
--
作者：
D. Gorenflo;J. Goetz;K. Bier
通讯作者：
K. Bier
H2 Behältersieden（Sieden in freier Konvektion）
DOI：
--
发表时间：
2013
期刊：
影响因子：
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作者：
D. Gorenflo
通讯作者：
D. Gorenflo
高粘性流体在垂直环形管中的流动沸腾
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
M. Wienecke;A. Luke;D. Gorenflo;R. Span
通讯作者：
R. Span