Answer to Question #180888 in Chemical Engineering for Abaya felix

Question #180888

CPT 307 ASSIGNMENT

The Figure below shows a cross section through an insulated heating pipe which is made from steel (k = 45 W / m K) with an inner radius of 150 mm and an outer radius of 155 mm. The pipe is coated with 100 mm thickness of insulation having a thermal conductivity of k = 0.06 W / m K. Air at Ti = 60°C flows through the pipe and the convective heat transfer coefficient from the air to the inside of the pipe has a value of hi = 35 W / m2 K. The outside surface of the pipe is surrounded by air which is at 15°C and the convective heat transfer coefficient on this surface has a value of ho = 10 W / m2 K. Calculate the heat loss through 50 m of this pipe. 

 


1
Expert's answer
2021-04-14T07:43:16-0400


The insulation radius which resistance to heat flow is minimum, and consequently heat flow rate is maximum is called “critical radius”.

The critical radius of insulation for a cylindrical body:

rcylinder=kh{r_{cylinder}} = \frac{k}{h}

where, k = conductivity of insulation, h = convective heat transfer coefficient of outer body.

k=0.06W/mK,h=10W/m2Kk = 0.06 W/mK, \quad h = 10 W/m^2KK


rc=kinsulationhoutside=0.0610=0.006m=6mm\begin{aligned} {r_c} &= \dfrac{k_{insulation}}{h_{outside}} \\ \\ &= \dfrac{0.06}{10} \\ \\ &= 0.006m\\ &= 6mm \end{aligned}

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!

Leave a comment