1 / 27

College Physics (Thermodynamics): Mean Free Path, Diffusion, Thermal Conductivity, and Viscosity

This article discusses concepts in college physics related to mean free path, diffusion, thermal conductivity, and viscosity. It covers topics such as Maxwell velocity distribution, most probable speed, mean free path, and transport coefficients. The information is supported by references and experimental results.

johnryan
Download Presentation

College Physics (Thermodynamics): Mean Free Path, Diffusion, Thermal Conductivity, and Viscosity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. 大学物理(热学) • Mean Free Path • Diffusion, Thermal conductivity, and Viscosity 2006-10-12

  2. ni the number of moleculesof in vy vy + dvy Equilibrium distribution dn isthe number of molecules nearv

  3. Meaning of dn/N amongN molecules, how many are near v probability that one molecule is near v proportional to dvx ...

  4. Isotropic assumption The solution is The probability should be normalized

  5. a each normalized a 12

  6. Known while

  7. For unit volume Maxwell velocity distribution

  8. Maxwell speed distribution Most probable speed For one molecule, what speed is most possible? Among N molecules, what is the speed most molecules have in unit interval?

  9. Maxwellian can be written as

  10. The average speed

  11. In an interval of Dt, number of collisions is

  12. Then mean free path is

  13. where the mean relative speed is

  14. optional Reference L. E. Reichl, A Mordern Course in Statistical Physics. University of Texas Press, Austin 1980 pp458

  15. Then mean free path is Only a factor different from dimension analysis result.

  16. Conduction Transport phenomena Heat transfer : conduction convection thermal radiation diffusion viscosity thermal conductivity Fourier’s law

  17. Diffusion Fick’s law Viscosity 6

  18. Microscopic theory of transport coefficients

  19. For mass transport, In general:

  20. Similarly

  21. Hydrogen under STP r = 1.12×10−10m

  22. Experimental results:

More Related