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R134a-DMF垂直管内鼓泡吸收特性研究
孔祥强,李华昭,李见波
0
(山东科技大学机械电子工程学院)
摘要:
为研究垂直管内R134a-DMF(二甲基甲酰胺)鼓泡吸收过程的热、质传递特性,本文搭建了垂直管内鼓泡吸收实验测试装置,构建了管内R134a被R134a-DMF混合溶液鼓泡吸收过程的热、质传递数学模型。进一步通过模型分析了当吸收压力为0.35 MPa,蒸气入口温度为5 ℃,稀溶液入口质量流量为12.0 kg/h时,吸收过程搅拌流、弹状流、泡状流和单相流的流型变化特点,并得到了吸收高度随入口参数的变化规律。结果表明:吸收过程中弹状流占据吸收高度的比例最大;随着吸收过程的进行,吸收速率不断增大,蒸气温度变化幅度最大,其次是相界面温度和溶液温度,冷却水温度变化幅度最小,且各温度变化在搅拌流流态时最大,在泡状流流态时最小;当稀溶液的入口质量分数为0.4,入口温度为45 ℃时,蒸气入口质量流量从1.0 kg/h升至2.5 kg/h,吸收高度从0.44 m升至1.88 m。
关键词:  吸收式制冷  制冷剂  鼓泡  传热系数
DOI:
投稿时间:2021-06-09修订日期:2021-10-03
基金项目:山东省自然科学基金(ZR2020QE208),山东省研究生导师指导能力提升项目(SDYY17037),海洋能源利用与节能教育部重点实验室(大连理工大学)开放基金,山东科技大学研究生导师指导能力提升计划项目(KDYC17009)
Study on Bubble Absorption Characteristics of R134a-DMF in Vertical Tube
Kong Xiangqiang,Li Huazhao,Li Jianbo
(College of Mechanical and Electronic Engineering, Shandong University of Science and Technology)
Abstract:
To study the heat and mass transfer characteristics of an R134a-DMF (Dimethylformamide) bubble absorption process in a vertical tube, an experimental device for bubble absorption in a vertical tube was fabricated, and a mathematical model of heat and mass transfer in the bubbling absorption process of R134a by an R134a-DMF solution was established. The characteristics of flow patterns of churn flow, slug flow, bubble flow, and single-phase flow were simulated and analyzed at an absorption pressure of 0.35 MPa, a vapor inlet temperature of 5 °C, and a weak solution inlet mass flow rate of 12.0 kg/h, by which the variation in absorption height with inlet parameters was obtained. The proportion of slug flow to the absorption height was the largest in the absorption process. As the absorption process continued, the rate of absorption increased. The variation in the vapor temperature was the largest, followed by the variations in phase interface temperature and solution temperature, and the variation in the cooling water temperature was the smallest. Furthermore, the variations at different temperatures were the largest in the churn flow state and the smallest in the bubble flow state. At the weak solution inlet mass fraction of 0.4 and the weak solution inlet temperature of 45 °C, the absorption height increased from 0.44 m to 1.88 m when the vapor inlet mass flow rate varied from 1.0 kg/h up to 2.5 kg/h.
Key words:  absorption refrigeration  refrigerant  bubble  coefficient of heat transfer

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