Solving Heat Transfer Q: Find Formula for T2 in Steel Pipe

[FChebli]

1. The problem statement:

(a)Concider a stainless steel hollow pipe containing a saturated steam and has length L, cooled by convection & radiation. Find formula for T2.

(b) Another question "Not related to the previous one": How would I know if a gas has gone turbulent?

2. Homework Equations :

For (a): Q = 2 Pai K (T1 - T2) / ln (r2 / r1)

For (b): Re = e u l / M ??

3. The Attempt at a Solution :

(a) Do I ignore the saturated steam, and re-write the equation (a) with respect to T2 only??

Thank you!

 

[Valkarie]

For (a): Yes, you can ignore the saturated steam and re-write the equation with respect to T2 only. The equation for the heat transfer rate is given by: Q = 2πK(T1 - T2)/ln(r2/r1). Where K is the thermal conductivity of the pipe, T1 is the outer wall temperature, T2 is the inner wall temperature, r2 and r1 are the outer and inner radii of the pipe respectively. So, the equation for T2 can be written as: T2 = T1 - (Q ln(r2/r1))/(2πK)