Hot water flows on the outside of a pipe wall. Cold water flows on the inside of

Question

Hot water flows on the outside of a pipe wall. Cold water flows on the inside of a pipe wall. The convection coefficients are h=1400 for the cold water and h=4200 for the hot water. Use 0.00314m2 for the surface areas of each pipe through which the heat is transferred. Find the heat transferred from the hot water to the cold water. Where D2 = the outer diameter = 1.1 cm Dl = the inner diameter = l.0 cm L = the length of the pipe = 0.1 m k = is the conduction coefficient of the pipe=19W/m degree C

Explanation / Answer

Let the surface temperatures of inner surface of the pipe be T1 and of outer surface of the pipes be T2

At the inner surface

h*A*dT = k*A*dT/dx

1400*0.00314*(T1 - 10) = 19*0.00628*dT/0.001

At the outer surface

4200*0.00314*(98 - T2) = 19*0.00691*dT/0.001

dT = T2 - T1

This gives T2 = 75.005 C and T1 = 72.695 C

Therefore Heat transferred from hot water to cold water = 1400*0.00314*(72.695 - 10) = 275.607 J

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.