# What is the total amount of heat transferred? At a flow rate of 0.1 kg/s for cold water,… 1 answer below »

a) (12%) What is the total amount of heat transferred? At a flow rate of 0.1 kg/s for cold water, what is

the water temperature when it exits the inner pipe? Confirm it is close to (within 5 C difference from) the

inlet temperature, 20 C.

b) (only 2%) What sketch below represents the temperature change along x-direction in the diagram?

c) (12%) Construct the thermal circuit, label the temperatures and resistors.

d) (18%) What is the Nusselt number and convection coefficient of water in inner pipe?

e) (26%) What is the Nusselt number and convection coefficient of oil in the annulus pipe? What is the

inner pipe temperature? (Is/are the assumption(s) you took earlier consistent with your calculation?)

f) (14%) How long does the pipe need to be in order to cool the oil from 120 to 50 C?

g) (12%) Now, the jacketed pipe is not insulated outside, and instead, it is exposed in quiescent air at a

?”#\$,& = 20 ?. Construct the thermal circuit, label the temperatures and resistors.

h) (bonus 10%) Continue from g) What is the free convection coefficient h”#\$, if the surface temperature

of the outer pipe is at 53 C? (Use Table 9.2.) (another bonus 10%) do you think this free convection due

to the exposure to the air will increase or decrease the heat transfer of oil? By how much %. 