Can a hair dryer burn? Thermodynamic considerations....

[Merlin05]

Hi all,
I actually work in physics (quantum physics) but my thermodynamics knowledge is a bit lacking these days. The following problem has had me puzzled for quite a long time.

Basically, if I point the hot air coming out of a hairdryer at a target, will that target's temperature ever go higher than the temperature of the hot air? I recall reading somewhere that hairdryers product air at 60 degrees C, which is just below the threshold that can cause burning.

Thanks.

 

[BvU]

Burning of the skin, not bursting into flames, is what they probably mean.

 

[Nidum]

Free flowing air probably stays within temperature limits most of the time . Problem with all heat gun devices is that if exit duct is partially blocked then temperature can rise considerably . Modern equipment is usually fitted with an over temperature trip out device or full thermostatic control for safety .

 

[Merlin05]

Free flowing air probably stays within temperature limits most of the time . Problem with all heat gun devices is that if exit duct is partially blocked then temperature can rise considerably . Modern equipment is usually fitted with an over temperature trip out device or full thermostatic control for safety .

Thanks for the reply.
To be clear, I'm talking about the hairdryer burning the skin, not the dryer bursting into flames. In fact I just gave the hairdryer as an example, I'm really interested in understanding the physics here: i.e. if I blow air at 60 degrees C at a wall can that wall's temperature exceed 60 degrees?

 

[nasu]

If that were possible, why not just blow air at room temperature and expect things to warm up?

 

[Merlin05]

If that were possible, why not just blow air at room temperature and expect things to warm up?

Thanks for that answer!

 

[Nidum]

It is possible to build machines which use a large flow of cold air to produce a small flow of hot air .

 

[A.T.]

if I blow air at 60 degrees C at a wall can that wall's temperature exceed 60 degrees?

If you blow hard enough:
https://en.wikipedia.org/wiki/Aerodynamic_heating