A shell-and-tube heat exchanger is used for cooling 47 kg/s of a process stream flowing through the tubes from 160 C to 100°C. This heat exchanger has a total of 100 identical tubes, each with an inside diameter of 2.5 cm and negligible wall thickness. The average properties of the process stream are: rho 950 kg/m3, k = 0.50 w/m. K, cp-3.5 kJ/kg-K and μα 2.0 mPa-s. The coolant stream is water (cp- 4.18 kJ/kg K) at a flow rate of 66 kg/s and an inlet temperature of 10 C, which yields an average shell-side heat transfer coefficient of 4.0 kW/m2-K. Calculate the tube length if the heat exchanger has

(a) a 1-shell pass and a 1-tube pass and
(b) a 1-shell pass and 4-tube passes 1.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.