Consider a packed bed of spheres, each of diameter 2 mm, at an initial temperature of 87.5°C. Cold water at 5.0°C is poured onto the bed at 0, producing a large convection coefficient about each sphere. Determine the magnitude of the rate, in °C/s, at which an individual sphere near the top surface of the bed is cooled at 0.1, 0.25, and 1 s. The spheres have thermophysical properties similar to Pyrex.

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.

Fluids at rest possess no flow energy. a)- true b)- false

Prove the equivalence between the two statements of the 2nd law of thermodynamics (i.e., a violation of one statement leads to the violatio the other statement)