Is thermal transpiration a real thing?

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In summary, thermal transpiration is a well-known concept in academia that was first theorized by Osborne Reynolds and published by James Clerk Maxwell. It explains how gas molecules flow from the cooler side to the hotter side in a porous plate, similar to how gas flows through the edges of the vanes in a Crookes radiometer.
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rhenretta
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I have a video on youtube about a crooke's radiometer, and one of the comments referred to a line from wikipedia about thermal transpiration:

The final piece of the puzzle, thermal transpiration, was theorized by Osborne Reynolds[3], but first published by James Clerk Maxwell[4] in the last paper before his death in 1879. Reynolds found that if a porous plate is kept hotter on one side than the other, the interactions between gas molecules and the plates are such that gas will flow through from the cooler to the hotter side. The vanes of a typical Crookes radiometer are not porous, but the space past their edges behaves like the pores in Reynolds's plate. On average, the gas molecules move from the cold side toward the hot side whenever the pressure ratio is less than the square root of the (absolute) temperature ratio. The pressure difference causes the vane to move, cold (white) side forward.

I also found a thread about this very subject several years back, but the one link I was interested in (a paper in arxiv) was outdated, and I couldn't find the article. None of the links on Google were very trustworthy.

I have a problem with this, because the warmer area would create an area of slightly higher pressure, and that would flow to the area of low pressure - the cool side. The idea that the gas would flow from cold to hot would violate my understanding of physics. Is the idea of thermal transpiration accepted in academia, or is it nothing but an analogous urban legend?
 
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Thermal transpiration is definitely a concept that is accepted in academia. According to the Wikipedia article, Osborne Reynolds theorized the idea and James Clerk Maxwell was the first to publish it in a paper before his death in 1879. It is an accepted concept in the scientific community and is not considered an urban legend. If you are still having trouble understanding how this works, you may want to take a look at some other resources on the subject or even ask an expert for help.
 

Related to Is thermal transpiration a real thing?

1. Is thermal transpiration a real phenomenon?

Yes, thermal transpiration is a real phenomenon that occurs in gases due to temperature differences.

2. How does thermal transpiration differ from diffusion?

Thermal transpiration is the movement of gas molecules from regions of low temperature to high temperature, while diffusion is the movement of molecules from high concentration to low concentration.

3. What causes thermal transpiration?

Thermal transpiration is caused by the difference in mean free path of gas molecules due to temperature differences. This results in a net flow of gas molecules from cold to hot areas.

4. Can thermal transpiration be observed in everyday life?

Yes, thermal transpiration can be observed in everyday life through various examples such as the movement of gas through a temperature gradient in a tube or the flow of air in a convection oven.

5. How is thermal transpiration studied in scientific research?

Thermal transpiration is studied through various experimental techniques such as pressure difference measurements, optical methods, and molecular beam techniques. These methods allow for the observation and measurement of gas flow due to temperature differences.

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