Effect of Boiling Condition on Vapor Concentration during Boiling of Liquid Mixture

沸腾条件对液体混合物沸腾过程中蒸气浓度的影响

• 批准号: 10650204
• 负责人: UTAKA Yoshio
• 金额: $ 2.24万
• 依托单位: Yokohama National University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650204/
• 关键词: Nucleate Boiling; Mixture; Generated Vapor Concentration; Condensation; Dew Point Method; Laser Absorption Method; 沸騰; 蒸気濃度; 気泡; 物質伝達

Recently, the utilization of the non-azeotropic working fluid in the cycle is developing for achieving high performance liquid-vapor two-phase cycle and for the various usage of the working fluid. It is important to clarify the characteristic of the vapor-liquid phase change process of the mixtures. The objective of the study is to clarify the effect of the boiling condition of liquid mixture in the nucleate boiling process on the composition of the generated vapor. The vapor concentration measurement was carried out in the bulk vapor layer in the saturated pool boiling process of water-ethanol and ethanol-acetone mixtures from the thin heated wires. Two kinds of measuring method ; the dew-point method by using the dew-point measurement and the known liquid-vapor equilibrium relation, and the laser light absorption method by using the property of infrared light absorption to the vapor of hydrocarbon were adopted. As the result, it was clarified that the vapor concentration in the bulk … More vapor layer which was generated by the nucleate boiling was in equilibrium with bulk liquid and was independent on the boiling conditions such as the degree of surface superheat and liquid layer height etc. Next, the change of the generated vapor temperature was measured in order to clarify the variations of the temperature and concentration change of vapor in the process of the bubble generation and departure. The vapor bubble, which was created on heating surface, had comparatively large degree of superheat. The selective condensation was occurred and the temperature also lowered in the process of the departure of the bubbles. As a result, the vapor in the bubbles attained to be in equilibrium with the bulk conditions almost at the height of 3-5 mm from the heating surface. Moreover, the temperature change of vapor bubble was determined by the elapsed time from the vapor bubble generation. Thus, it was clarified that the concentration of vapor layer existed in equilibrium with the bulk state in the system in which the steady boiling and condensation was occurred. Less

近年来，为了实现高性能的液-汽两相循环以及工作流体的多种用途，在循环中使用非共沸工作流体正在发展。阐明混合物的气-液相变过程的特征具有重要意义。研究的目的是阐明核态沸腾过程中液体混合物的沸腾条件对产生的蒸气的组成的影响。在水-乙醇和乙醇-丙酮混合物的饱和池沸腾过程中，通过细加热丝在本体蒸气层中进行蒸气浓度测量。两种测量方法；采用了露点法和激光吸收法，露点法利用露点测量和已知的液汽平衡关系，激光吸收法利用烃蒸气对红外光的吸收特性。结果表明，泡核沸腾产生的本体蒸汽层中的蒸气浓度与本体液体处于平衡状态，且与表面过热度、液层高度等沸腾条件无关。接下来，测量了生成蒸气温度的变化，以明确气泡产生和离开过程中蒸气温度和浓度变化。受热面产生的气泡具有较大的过热度。在气泡离开的过程中发生选择性冷凝，温度也降低。结果，气泡中的蒸气几乎在距离加热表面3-5mm的高度处与本体条件达到平衡。此外，通过从蒸汽泡产生起经过的时间来确定蒸汽泡的温度变化。由此可见，在发生稳定沸腾和冷凝的系统中，蒸气层的浓度与本体状态处于平衡状态。较少的

项目成果

Utaka, Y. and Sai, S.: "Vapor Concentration in Boiling Process of Liquid Mixture (2nd Report)"Proc. 37th National Heat Transfer Symposium of Japan. (to be published).

Utaka, Y. 和 Sai, S.：“液体混合物沸腾过程中的蒸气浓度（第二次报告）”Proc。

宇高 義郎: "混合液の沸騰過程における生成蒸気濃度に関する研究(総報)"第37回日本伝熱シンポジウム講演論文集. (発表予定). (2000)

Yoshiro Udaka：“混合液体沸腾过程中产生的蒸气浓度的研究（综合报告）”第37届日本传热研讨会论文集（预定报告）（2000年）。

宇高義郎、崔正浩: "混合液の沸騰過程における生成蒸気濃度に関する研究(続報)"第37回日本伝熱シンポジウム講論集. (講演予定). (2000)

Yoshiro Utaka、Masahiro Choi：“混合液体沸腾过程中产生的蒸气浓度的研究（后续报告）”第37届日本传热研讨会论文集（预定讲座）。

6354 (1999)

6354 (1999)

Utaka, Y., Takahashi, K. and Tshuboi, T.: "An Investigation of Vapor Concentration during Boiling of Liquid Mixture"Proc. Fifth ASME/JSME Joint Thermal Engineering Conference. AJTE99-6354. (1999)

Utaka, Y.、Takahashi, K. 和 Tshuboi, T.：“液体混合物沸腾过程中蒸气浓度的研究”Proc。