# An engineer operates a counter-flow shell-and-tube heat exchanger. It is known that the A fluid (specific…

An engineer operates a counter-flow shell-and-tube heat

exchanger. It is known that the A fluid (specific heat is 1.0

J/g*°C) flows into the outside of the tube at a mass flow rate of

100 g/hr. The inlet temperature is 90 ° C and the outlet

temperature is At 70 ° C, the B fluid flows into the tube. The

inlet temperature is 20 ° C and the outlet temperature is 65 ° C.

If the heat transfer effective area is 20 m 2 , answer

the following questions:

(1) What is the logrithm average temperature difference (ΔTln)

for °C?

(2) What is the total heat transfer coefficient (Uo) J/(hr*m2

*°C)? (ln2=0.693)