- #1
lirexin
- 4
- 0
Can anyone help with whis question?
Just provided with the answerw don't know how to get there
A heat pipe is a simple device which can be used to transfer heat over considerable
distances using only small temperature differences. It consists of a sealed tube filled
with an appropriate fuid. The dryness fraction of the fuid is usually about 0.1. If
the tube is then supported with one end above the other, and the lower end heated,
then that part of working substance which is liquid collects there and boils. If the
upper end of the tube is cooled, then the vapour condenses there, and the conden-
sate is returned by gravity to the lower end. The result is a heat transfer from the
bottom to the top of the tube, with no temperature differences.
If a heat pipe filled with ammonia were to be used to transfer heat from tightly
grouped electronic components to remote heat sinks, what would be their internal
pressure?
i) at -10 C (equipment turned o in a cold climate)
ii) at 20 C
iii) at 50 C (maximum operating temperature).
The answers are
i) 0.291 MPa
ii) 0.857 MPa
iii) 2.033 MPa
Just provided with the answerw don't know how to get there
A heat pipe is a simple device which can be used to transfer heat over considerable
distances using only small temperature differences. It consists of a sealed tube filled
with an appropriate fuid. The dryness fraction of the fuid is usually about 0.1. If
the tube is then supported with one end above the other, and the lower end heated,
then that part of working substance which is liquid collects there and boils. If the
upper end of the tube is cooled, then the vapour condenses there, and the conden-
sate is returned by gravity to the lower end. The result is a heat transfer from the
bottom to the top of the tube, with no temperature differences.
If a heat pipe filled with ammonia were to be used to transfer heat from tightly
grouped electronic components to remote heat sinks, what would be their internal
pressure?
i) at -10 C (equipment turned o in a cold climate)
ii) at 20 C
iii) at 50 C (maximum operating temperature).
The answers are
i) 0.291 MPa
ii) 0.857 MPa
iii) 2.033 MPa