Increasing Air Temperature in a Small Metal Box

[sid_galt]

If you have air moving at 10-20 meters/second through a very small (8mm3 volume) metal box open on both ends and you want to increase its temperature by around 1.3 times as it passes through the box, what is the most efficient way to do it taking into account the heat lost to the box, surroundings etc.?

I am guessing burning fuel as a wire won't be able to heat the air fast enough. Or are there other better ways?

 

[Gokul43201]

If you have air moving at 10-20 meters/second through a very small (8mm3 volume) metal box open on both ends and you want to increase its temperature by around 1.3 times as it passes through the box, what is the most efficient way to do it taking into account the heat lost to the box, surroundings etc.?

I am guessing burning fuel as a wire won't be able to heat the air fast enough. Or are there other better ways?

..."increase its temperature by around 1.3 times" ? Are you talking about absolute temperature, in Kelvin ?

The standard way is with a heater coil with lots of fins for greater surface area. But this would not work for your miniscule box. I recommend heating the box itself - putting anything inside the box will add a significant flow impedance.

 

[FredGarvin]

Do you have to heat just the box? You could easily use some pipe heaters and heat the sections of pipe coming into and going out of the box as well. Whatever you do it is going to have to be pretty hot to increase the temperature of air moving that fast.