3. You have been asked to investigate the feasibility of employing hot air (70 C) forced convecti...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
Problem 3 (20 points) A cross-flow heat exchanger consists of a bundle of 32 tubes in a long duct. Hot water at 150°C and a mean velocity of 0.5 m/s enters the tubes having inner and outer diameters of 10.2mm and 12.5mm and has to be cooled to 136°C. The tubes are made of steel of thermal conductivity k-40 W/m.K. Air at 10°c enters the exchanger (unfinned) with a volumetric flow rate of 1.0 m3/s. The convective heat transfer coefficient...