Self-thermophoresis and thermal self-diffusion in liquids and gases
This paper demonstrates the existence of self-thermophoresis, a phenomenon whereby a virtual thermophoretic force arising from a temperature gradient in a quiescent single-component liquid or gas acts upon an individual molecule of that fluid in much the same manner as a “real” thermophoretic force...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2011
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| Online Access: | http://hdl.handle.net/1721.1/60399 |
| _version_ | 1811086936970887168 |
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| author | Brenner, Howard |
| author2 | Massachusetts Institute of Technology. Department of Chemical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Chemical Engineering Brenner, Howard |
| author_sort | Brenner, Howard |
| collection | MIT |
| description | This paper demonstrates the existence of self-thermophoresis, a phenomenon whereby a virtual thermophoretic force arising from a temperature gradient in a quiescent single-component liquid or gas acts upon an individual molecule of that fluid in much the same manner as a “real” thermophoretic force acts upon a macroscopic, non-Brownian body immersed in that same fluid. In turn, self-thermophoresis acting in concert with Brownian self-diffusion gives rise to the phenomenon of thermal self-diffusion in single-component fluids. The latter furnishes quantitative explanations of both thermophoresis in pure fluids and thermal diffusion in binary mixtures (the latter composed of a dilute solution of a physicochemically inert solute whose molecules are large compared with those of the solvent continuum). Explicitly, the self-thermophoretic theory furnishes a simple expression for both the thermophoretic velocity U of a macroscopic body in a single-component fluid subjected to a temperature gradient ∇T, and the intimately related binary thermal diffusion coefficient DT for a two-component colloidal or macromolecular mixture. The predicted expressions U=−DT∇T≡−βDS∇T and DT=βDS (with β and DS the pure solvent’s respective thermal expansion and isothermal self-diffusion coefficients) are each noted to accord reasonably well with experimental data for both liquids and gases. The likely source of systematic deviations of the predicted values of DT from these data is discussed. This appears to be the first successful thermodiffusion theory applicable to both liquids and gases, a not insignificant achievement considering that the respective thermal diffusivities and thermophoretic velocities of these two classes of fluids differ by as much as six orders of magnitude. |
| first_indexed | 2024-09-23T13:37:10Z |
| format | Article |
| id | mit-1721.1/60399 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:37:10Z |
| publishDate | 2011 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/603992022-10-01T16:05:07Z Self-thermophoresis and thermal self-diffusion in liquids and gases Brenner, Howard Massachusetts Institute of Technology. Department of Chemical Engineering Brenner, Howard Brenner, Howard This paper demonstrates the existence of self-thermophoresis, a phenomenon whereby a virtual thermophoretic force arising from a temperature gradient in a quiescent single-component liquid or gas acts upon an individual molecule of that fluid in much the same manner as a “real” thermophoretic force acts upon a macroscopic, non-Brownian body immersed in that same fluid. In turn, self-thermophoresis acting in concert with Brownian self-diffusion gives rise to the phenomenon of thermal self-diffusion in single-component fluids. The latter furnishes quantitative explanations of both thermophoresis in pure fluids and thermal diffusion in binary mixtures (the latter composed of a dilute solution of a physicochemically inert solute whose molecules are large compared with those of the solvent continuum). Explicitly, the self-thermophoretic theory furnishes a simple expression for both the thermophoretic velocity U of a macroscopic body in a single-component fluid subjected to a temperature gradient ∇T, and the intimately related binary thermal diffusion coefficient DT for a two-component colloidal or macromolecular mixture. The predicted expressions U=−DT∇T≡−βDS∇T and DT=βDS (with β and DS the pure solvent’s respective thermal expansion and isothermal self-diffusion coefficients) are each noted to accord reasonably well with experimental data for both liquids and gases. The likely source of systematic deviations of the predicted values of DT from these data is discussed. This appears to be the first successful thermodiffusion theory applicable to both liquids and gases, a not insignificant achievement considering that the respective thermal diffusivities and thermophoretic velocities of these two classes of fluids differ by as much as six orders of magnitude. 2011-01-07T15:27:52Z 2011-01-07T15:27:52Z 2010-09 2010-05 Article http://purl.org/eprint/type/JournalArticle 1539-3755 1550-2376 http://hdl.handle.net/1721.1/60399 Brenner, Howard. "Self-thermophoresis and thermal self-diffusion in liquids and gases." Physical Review E 82.3 (2010): 036325. © 2010 The American Physical Society en_US http://dx.doi.org/10.1103/PhysRevE.82.036325 Physical Review E Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Brenner, Howard Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title | Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title_full | Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title_fullStr | Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title_full_unstemmed | Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title_short | Self-thermophoresis and thermal self-diffusion in liquids and gases |
| title_sort | self thermophoresis and thermal self diffusion in liquids and gases |
| url | http://hdl.handle.net/1721.1/60399 |
| work_keys_str_mv | AT brennerhoward selfthermophoresisandthermalselfdiffusioninliquidsandgases |