- #1

- 807

- 8

**"What is the heat flow rate [...]?"**

## Homework Statement

__The problem is__:

"

*A copper tube (length, 3.0 m; inner diameter, 1.500 cm; outer diameter, 1.700 cm) extends across a 3.0-m long vat of rapidly circulating water maintained at 20 °C. Live steam at 100 °C passes through the tube.*

(a) What is the heat flow rate from the steam into the vat?

(b) How much steam is condensed each minute?

(For copper, ##k_T## = 1.0 cal/s ⋅ cm ⋅ °C.)"

(a) What is the heat flow rate from the steam into the vat?

(b) How much steam is condensed each minute?

(For copper, ##k_T## = 1.0 cal/s ⋅ cm ⋅ °C.)

The solution is attached as TheSolution.jpg.

## Homework Equations

##ΔQ/Δt = ####k_T## ##A## ##ΔT/L##

## The Attempt at a Solution

When looking at the provided solution, I am, basically, confused about the assumptions made and the geometries involved.

To elaborate, I am confused as to why the solution deemed it was necessary to approximate the tube wall as a flat sheet. (Also, how exactly does a tube WALL look like? - I wasn't able to find anything useful on Google Images.)

Also, it is probably because I am having trouble visualizing the geometries in this problem but, I don't see why the inner and outer surface areas are being averaged.

Lastly, I don't see why we're assuming the hypothetical plate has a thickness of 0.100 cm.

Any help in understanding how this problem is done would be greatly appreciated!