A5-cm-external-diameter, 10-m-long hot-water pipe at 80°c loses heat to the surrounding air at 16°c by natural convection with a heat transfer coefficient of 25 w/m2·k. determine the rate of heat loss from the pipe by natural convection.

Atank with constant volume contains 2.27 kg of a mixture of water phases (liquid-vapor). in the initial state the temperature and the quality are 127 °c and 0.6, respectively. the mixture is heated until the temperature of 160 oc is reached. illustrate the process in a t-v diagram. then, determine (1) the mass of the vapor in kg at the initial state, (2) the final pressure in kpa.

A5 kg block of fe is dropped into a very large vat of water. the fe and water initial temperatures are 95 and 25 c, respectively. the fe final temperature is 25 c and the water can be treated as a thermal reservoir,. treated as a thermal reservoir take the water to be the system and determine the entropy generation. report vour answer in kj/k.

Asolid steel sphere (k=63.9 w m-1 k-1 , ? =7832 kg m-3 , c=0.523 kj kg-1 k-1 ), 100 mm in diameter is initially at a uniform temperature of 500o c and is suddenly quenched in a large oil bath for which t? = 100o c and h = 3200 w m-2 k-1. estimate the time required for the sphere to cool to 200o c and to 110o c