Air at t1 = 24°c, p1 = 1 bar, 50% relative humidity enters an insulated chamber operating at steady state with a mass flow rate of 3 kg/min and mixes with a saturated moist air stream entering at t2 = 7°c, p2 = 1 bar. a single mixed stream exits at t3 = 17°c, p3 = 1 bar. neglect kinetic and potential energy effects.
1. determine the rate of entropy production, in kj/min. k.

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa.s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)