q3

(a) A jacketed 2.5m-diameter agitated vessel without baffles is being used to heat a liquid which is at 350K. The agitator is 0.75m in diameter and is a paddle type rotating at 100rpm. Hot water is in the heating jacket. The wall surface temperature is constant at 400K. The liquid has the following bulk physical properties: =981kg/m3,cp=2800J/kg.K,k=0.183W/m.K, and =1.25Pa.s at 350K and 0.064Pa.s at 400K. Calculate the heat-transfer coefficient to the wall of the jacket. [6] (b) What is roughness factor and does the roughness factor affect the mass transfer, heat transfer and fluid flow in the equipment? [1+3=4]