沸腾传热管表面换热系数测试方法研究

根据处理测试数据的实际需要,提出了一种基于局部热流密度并应用计算机程序来处理实验数据,从而确定沸腾传热管的传热性能的方法.通过对一种表面强化沸腾管和一种制冷剂的实验数据进行处理,获得了管内外对流换热关系式,进而使用数值计算分离出管外换热系数,可用于指导水平单管沸腾换热实验设计和换热器设计.     

纳米溴化锂溶液稳定性及其沸腾温度研究

对既有溴化锂溶液、纳米微粒及其相应分散剂配制的纳米溶液,对比测试其与纯溴化锂溶液的表面张力和沸腾温度,探讨了该纳米溶液的热物性及稳定性。实验发现,添加纳米微粒溶液的表面张力明显降低,经过温度工艺处理后,发现溶液中纳米微粒的颗粒度降低,纳米微粒在溴化锂溶液中几乎完全溶解,纳米溶液显现出很好的稳定性,其表面张力和沸腾温度均比纯溴化锂溶液有所降低。研究表明,最佳组份配制的纳米溶液与纳米微粒和相关分散剂有关,经过严格温度处理工艺流程,可获得稳定性、热物性良好的纳米溴化锂溶液,有利于在工程中应用。     

快堆组件盒壁破损机理模型的建立与验证

快堆内发生超设计基准事故后，故障组件盒会发展到沸腾池，事故下一步的传播取决于池壁破损。文章采用机理建模方法，对3种主要盒壁破损机理建立模型，并在法国SCARABEE堆内实验中的BE+3和PV-A实验以及堆外GEYSER实验上进行了模型验证，模型计算结果与实验结果吻合较好。根据模型计算结果，对PV-A实验的池壁破损给予了合理解释，总结出快堆池壁破损的相关结论，并对堆内发生燃料-冷却剂相互作用（FCI）的可能性进行分析，给出了相关结论。     

A suggestion to enhance pool boiling heat transfer on a vertical tube surface

To find a way of improving pool boiling heat transfer on a vertical tube surface, a revised annulus has been investigated experimentally. The annulus with closed bottoms has a shorter outer tube than the inside heated tube. For the study, three tube diameters (16.5, 19.1, and 25.4mm) and water at atmospheric pressure were used. The annular gap covers from 3.2 to 19.3mm in size and is generated by several glass tubes, which are fabricated around the heated tube. To clarify effects of the revised annulus on heat transfer, experimental results of the annulus were compared to the data of unrestricted tubes. The heat transfer coefficients for the revised annulus increased remarkably in comparison to the unrestricted tube. This paper was recommended for publication in revised form by Associate Editor Jae Young Lee Myeong-Gie Kang received his B.S. degree in Precision Mechanical Engineering from Pusan National University, Korea, in 1986. He then received his M.S. and Ph.D. degrees from KAIST in 1988 and 1996, respectively. Dr. Kang is currently a Professor at the Department of Mechanical Engineering Education at Andong National University in Andong, Korea. He has served as an engineer and researcher in KEPCO for 7 years. His research interests include pool boiling heat transfer, flow induced vibration, and nuclear thermo-hydraulics.     

流动欠热沸腾起始点计算模型的分析研究

介绍了国外几个典型的计算流动欠热沸腾起始点的模型，对几个有代表性的模型进行了分析比较。用本实验数据和国外资料发表的几组数据对几个模型的计算关系式进行了验证，给出了推荐使用的计算流动欠热沸腾起始点的关系式。     

煮沸对自来水中氯仿含量的影响

为了解管网末梢自来水及其在加热煮沸过程中致癌有机物——氯仿（CHCl3）含量的变化，采用不同的加热器、运用不同的加热方式对我国南方某地区管网末梢的自来水进行了加热煮沸处理，并对不同加热煮沸时间的水样进行了色质联机分析。结果发现，氯仿含量与热水器的功率、加热煮沸的方式及水中自由余氯含量均有关系。不管采用何种原水、何种加热器和加热方式，若煮沸后使水保持数分钟的沸腾状态均可使水中的氯仿含量降低到5μg／L以下的安全水平。     

A New Group Contribution Method for Estimating Boiling Point of Heavy Oil

The boiling point of feedstock is an important process design parameter for petroleum system. In heavy petroleum fractions that boil above 524°C, it is difficult to explicitly determine the boiling point due to limitation of analytical capability. In this article, a modified Cordes-Rarey group contribution method for estimating boiling point of heavy oil was developed on the basis of structure parameters of oil fractions. Narrow fractions of heavy oil were prepared by using the supercritical fluid extraction and fractionation (SFEF). The average boiling points of light SFEF fractions were measured up to 680°C. Elemental analyses and the ¹H and ¹³C-NMR spectra of the SFEF fractions were obtained to determine structure parameters and construct average molecules of SFEF fractions. The results show that the boiling point was correlated with total atom number (except hydrogen) of SFEF fraction. The predicted boiling points for more than 60 SFEF fractions at 320-680°C derived from an Eastern Siberia crude and its blend with Daqing crude agree well with measured values within 2.04%. The predicted boiling points of normal alkanes and polycyclic aromatics are in agreement with literature data. It is suggested that the proposed group contribution method, in combination with the characterization data of SFEF fractions, can be used to estimate the average boiling points of heavy oil fractions up to 800°C.     

Effects of molecule number on nucleate boiling in a system

Canonical molecular distribution was introduced to analyze characteristics of nucleate boiling when the liquid molecular number is very small. The minimum bulk phase volume in which phase change was able to occur was determined from the thermodynamic theory of bubble formation in a superheated liquid and from the energy distribution of the molecules in the bulk phase at a given temperature and pressure. The energy level of active molecules nearly independently distributing in systems was determined from conservation of mass. The maximum superheat temperature necessary for boiling nucleation was found to relate to the bulk phase volume with the temperature increasing as the volume decreased. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(4): 258–264, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20061