Saturated liquid water flows through 2 cm ID stainless steel tubes at 200 g/s. The water is at 80oC and the inside surface of the tubes is 200oC. (a) Determine the convection heat transfer to the water per unit length of tube and (b) predict the convective heat transfer after ten years when the inside of the tubes is coated with a film so that the ID is now 1.9 cm. If scaling of the tube was creating the reduction of the tube diameter, that came accompanied with an increase in the tube wall roughness of 0.2mm, discuss if the increased tube roughness compared with the smooth tube wall will affect the heat transfer coefficient and how.

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.

Agas mixture consists of 8 kmol of h2 and 2 kmol of n2. determine the mass of each gas and the apparent gas constant of the mixture.

Find the minimum film thickness for a journal bearing with the data below. shaft diameter, d-50 mm, clearance ratio, cdratio? 0.001, shaft speed, n 2000 rpm; bearing length. i 200 mm; eccentricity ration, ? -0.55. ( note, cdratio-ca/d) the minimum film thickness is um