Context:
On Earth, with gravity, when heating a fluid, the particles gain thermal energy and decrease in density, and a difference in density throughout the fluid causes thermal energy transfered by movement of fluid (convection currents) to form, with hotter fluid moving in opposite direction of gravitaitonal acceleration.
On space, without gravity, when heating a fluid, there is no gravitational acceleration, hence convection currents arising from density difference.
JAXA has proven this on the ISS, but they state no convection occurs at all.
Problem:
However, as fluid pressure increases proportionally with temperature, the hotter fluid would have a higher partial pressure than the surrounding fluid. Would this pressure gradient not create a movement in fluid, such as pressure differences in the atmosphere creating wind flow? Or is this effect too negligeable to move, for example, water? Thank you
Best Answer
In a microgravity environment, the gas will heat and expand uniformly in all directions.
Due to diffusion and thermal conduction (followed by eventual thermal equilibrium of the whole region), there will be no significant temperature (and therefore pressure) differences in the entire region at any time, meaning there will not be any noticeable fluid motion as such.