{"title":"二元混合物液滴蒸发过程中的溶解和重力效应","authors":"Xiaoyan Ma, Khellil Sefiane, Rachid Bennacer, Xavier Lapert, Farid Bakir","doi":"10.1007/s12217-024-10105-z","DOIUrl":null,"url":null,"abstract":"<div><p>For small droplets undergoing phase change, gravity is generally considered negligible. In the case of binary droplets evaporation, convective flows can be induced due to various mechanisms, such as continuity, buoyancy and/or selective evaporation of one of the components. Convection can also be induced by surface tension gradients resulting from concentration variations along the interface. This study presents experimental results of evaporation for binary mixture droplets. We concurrently investigate sessile and pendant droplets to assess gravity’s impact on binary droplet evaporation. We examine compositions including, pure butanol, pure methanol, pure water, and 50% per volume mixtures of water-butanol and water-methanol, evaporating in a controlled atmosphere. In the case of water-butanol mixtures, the drops contact line ‘depins’ during the evaporation process whereas the case of water-methanol mixture, the contact line of the drops remains pinned most of the lifetimes. The analysis of the evaporation dynamics reveals differences in the evaporation of these two mixtures and the effect of orientation (gravity). For water-butanol mixtures the evaporation occurs in four stages linked to preferential evaporation of the more volatile component and the ensuing surface tension gradients. In the case of water-methanol mixtures, contact lines tend to be pinned during most of the lifetimes of drops. The evaporation rate of the mixture is found to be between the ones of the pure components, i.e. water and methanol. The case of sessile drops exhibits a slight enhancement in evaporation rate in the case of the sessile configuration compared to the pendant one for pure water and mixture cases, which is explained by density differences and buoyancy driven flows. Solutal Marangoni flows in the case of water-methanol mixtures are deemed weaker compared to water-butanol ones. The use of the two mixtures allowed to have a good comparison between two cases where solutal-Marangoni effect can be strong (water-butanol) and weak (water- methanol) influence. The densities of the two organic liquids also highlighted gravitational effect due to the large difference in vapor densities.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 2","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Solutal and Gravitational Effects during Binary Mixture Droplets Evaporation\",\"authors\":\"Xiaoyan Ma, Khellil Sefiane, Rachid Bennacer, Xavier Lapert, Farid Bakir\",\"doi\":\"10.1007/s12217-024-10105-z\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>For small droplets undergoing phase change, gravity is generally considered negligible. In the case of binary droplets evaporation, convective flows can be induced due to various mechanisms, such as continuity, buoyancy and/or selective evaporation of one of the components. Convection can also be induced by surface tension gradients resulting from concentration variations along the interface. This study presents experimental results of evaporation for binary mixture droplets. We concurrently investigate sessile and pendant droplets to assess gravity’s impact on binary droplet evaporation. We examine compositions including, pure butanol, pure methanol, pure water, and 50% per volume mixtures of water-butanol and water-methanol, evaporating in a controlled atmosphere. In the case of water-butanol mixtures, the drops contact line ‘depins’ during the evaporation process whereas the case of water-methanol mixture, the contact line of the drops remains pinned most of the lifetimes. The analysis of the evaporation dynamics reveals differences in the evaporation of these two mixtures and the effect of orientation (gravity). For water-butanol mixtures the evaporation occurs in four stages linked to preferential evaporation of the more volatile component and the ensuing surface tension gradients. In the case of water-methanol mixtures, contact lines tend to be pinned during most of the lifetimes of drops. The evaporation rate of the mixture is found to be between the ones of the pure components, i.e. water and methanol. The case of sessile drops exhibits a slight enhancement in evaporation rate in the case of the sessile configuration compared to the pendant one for pure water and mixture cases, which is explained by density differences and buoyancy driven flows. Solutal Marangoni flows in the case of water-methanol mixtures are deemed weaker compared to water-butanol ones. The use of the two mixtures allowed to have a good comparison between two cases where solutal-Marangoni effect can be strong (water-butanol) and weak (water- methanol) influence. The densities of the two organic liquids also highlighted gravitational effect due to the large difference in vapor densities.</p></div>\",\"PeriodicalId\":707,\"journal\":{\"name\":\"Microgravity Science and Technology\",\"volume\":\"36 2\",\"pages\":\"\"},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2024-03-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Microgravity Science and Technology\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s12217-024-10105-z\",\"RegionNum\":4,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENGINEERING, AEROSPACE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microgravity Science and Technology","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s12217-024-10105-z","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, AEROSPACE","Score":null,"Total":0}
Solutal and Gravitational Effects during Binary Mixture Droplets Evaporation
For small droplets undergoing phase change, gravity is generally considered negligible. In the case of binary droplets evaporation, convective flows can be induced due to various mechanisms, such as continuity, buoyancy and/or selective evaporation of one of the components. Convection can also be induced by surface tension gradients resulting from concentration variations along the interface. This study presents experimental results of evaporation for binary mixture droplets. We concurrently investigate sessile and pendant droplets to assess gravity’s impact on binary droplet evaporation. We examine compositions including, pure butanol, pure methanol, pure water, and 50% per volume mixtures of water-butanol and water-methanol, evaporating in a controlled atmosphere. In the case of water-butanol mixtures, the drops contact line ‘depins’ during the evaporation process whereas the case of water-methanol mixture, the contact line of the drops remains pinned most of the lifetimes. The analysis of the evaporation dynamics reveals differences in the evaporation of these two mixtures and the effect of orientation (gravity). For water-butanol mixtures the evaporation occurs in four stages linked to preferential evaporation of the more volatile component and the ensuing surface tension gradients. In the case of water-methanol mixtures, contact lines tend to be pinned during most of the lifetimes of drops. The evaporation rate of the mixture is found to be between the ones of the pure components, i.e. water and methanol. The case of sessile drops exhibits a slight enhancement in evaporation rate in the case of the sessile configuration compared to the pendant one for pure water and mixture cases, which is explained by density differences and buoyancy driven flows. Solutal Marangoni flows in the case of water-methanol mixtures are deemed weaker compared to water-butanol ones. The use of the two mixtures allowed to have a good comparison between two cases where solutal-Marangoni effect can be strong (water-butanol) and weak (water- methanol) influence. The densities of the two organic liquids also highlighted gravitational effect due to the large difference in vapor densities.
期刊介绍:
Microgravity Science and Technology – An International Journal for Microgravity and Space Exploration Related Research is a is a peer-reviewed scientific journal concerned with all topics, experimental as well as theoretical, related to research carried out under conditions of altered gravity.
Microgravity Science and Technology publishes papers dealing with studies performed on and prepared for platforms that provide real microgravity conditions (such as drop towers, parabolic flights, sounding rockets, reentry capsules and orbiting platforms), and on ground-based facilities aiming to simulate microgravity conditions on earth (such as levitrons, clinostats, random positioning machines, bed rest facilities, and micro-scale or neutral buoyancy facilities) or providing artificial gravity conditions (such as centrifuges).
Data from preparatory tests, hardware and instrumentation developments, lessons learnt as well as theoretical gravity-related considerations are welcome. Included science disciplines with gravity-related topics are:
− materials science
− fluid mechanics
− process engineering
− physics
− chemistry
− heat and mass transfer
− gravitational biology
− radiation biology
− exobiology and astrobiology
− human physiology