| 摘要: |
| 为探究用于工业真空制备二元冰的最佳工况，本文基于静态闪蒸理论，设计并搭建了一套固体吸附条件下乙醇溶液真空闪蒸制冰实验系统。在同一初始压力下（100 Pa），研究了不同乙醇浓度、环境温度和多壁碳纳米管（MWCNT）尺寸对静态闪蒸制冰特性的影响。结果表明：乙醇的添加在防止重结晶的同时可以降低蒸馏水真空闪蒸制冰的过冷度，较高浓度的乙醇溶液不利于闪蒸制冰，5%质量浓度的乙醇溶液的闪蒸特性稳定，可将蒸馏水过冷度降低60.62%，较适合静态闪蒸制冰；随着环境温度的升高，闪蒸室内溶液的闪蒸量增大，随着环境温度从10 ℃升至20 ℃，闪蒸率从25.45%增至44.04%。较低的环境温度有利于真空闪蒸制冰；随着添加的MWCNT粒径的减小，乙醇溶液的过冷度减小，当MWCNT外径为5~18 nm时，真空闪蒸的含冰率相对于5%质量浓度的乙醇溶液提高了51.45%，相对于蒸馏水提高了38.22%。过冷度相对于5wt%乙醇溶液降低了24.36%，相对于蒸馏水降低了70.21%，对于减小蒸馏水过冷度和提高含冰率效果显著。 |
| 关键词: 乙醇溶液 真空 蒸发 过冷度 含冰率 |
| DOI： |
| 投稿时间：2018-03-26 修订日期：2018-06-04
|
| 基金项目:国家自然科学基金（51376115）资助项目。 |
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| Experimental Study of Ethanol Solution Vacuum Flash Characteristics Under the Effect of Multi-walled Carbon Nanotube |
|
Zhang Xuelai, Jia Xiaoya, Wang Zhangfei, Zheng Qinyue, Gan Wei, Han Xingchao, Jotham Muthoka Munyalo
|
| (Institute of Cool Thermal Storage Technology, Shanghai Maritime University) |
| Abstract: |
| To study the optimum operating condition of industrial ice making, an experimental system of the vacuum flash of ethanol solution under adsorption was designed based on the theory of flash evaporation. Under the same initial flash pressure (100 Pa), the effects of concentration, environment temperature, and size of multi-walled carbon nanotube (MWCNT) on the flash properties were studied. The results indicated that adding ethanol could not only avoid recrystallization but also decrease the supercooling degree of water. Higher concentrations were found to be adverse to the flash process. The flash property of 5% mass concentration of ethanol was stable, and the supercooling degree of water could be decreased by as much as 60.62%. With the rise in the environment temperature, the flash rate increased as the flash percent factor increased from 25.45% to 44.04% for an increase in the environment temperature from 10 °C to 20 °C. Thus, lower environment temperatures were shown to be beneficial to the flash process. With the decrease in the practical size of MWCNT, the supercooling of the MWCNT-ethanol solution decreased. The ice packing factor (IPF) of the solution to which 5–18 nm MWCNT was added was 51.45% higher than that of the 5% mass concentration ethanol and 38.22% higher than that of water. The supercooling degree of the solution was 24.36% smaller than that of ethanol and 70.21% smaller than that of water, which shows the MWCNT-ethanol solution has a significant effect on reducing the supercooling degree of water and improving the IPF. |
| Key words: ethanol solution vacuum evaporation supercooling degree IPF |
