Two pipes are buried in an insulating material having k =0.8 W/m· ◦C. One pipe is 10 cm in diameter and carries a hot fluid at 300◦C while the other pipe is 2.8 cm in diameter and carries a cool fluid...

Two pipes are buried in an insulating material having k =0.8 W/m· ◦C. One pipe is
10 cm in diameter and carries a hot fluid at 300◦C while the other pipe is 2.8 cm in
diameter and carries a cool fluid at 15◦C. The pipes are parallel and separated by a
distance of 12 cm on centers. Calculate the heat-transfer rate between the pipes per
meter of length.