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A blending tank is used to mix two different components, A and B . Due to enthalpy of mixing, the temperature within the vessel would

A blending tank is used to mix two different components, A and B. Due to enthalpy of mixing, the temperature within the vessel would increase if no cooling method is supplied. The vessel has an internal diameter of 5m and straight side height of 15m. The liquid level in the tank is maintained at 11m. The process fluids have a liquid density of 1200kgm3, a viscosity of 25cP, a thermal conductivity of 350mWm-K, and a heat capacity of 5.3kJkg-K.
To remove the process heat, treated cooling water is supplied through a 180,7cm outer diameter half-piped jacket. The inside diameter of the pipe is 6.2cm. The cooling water is supplied at 25C with a flow rate of 0.01m3sec, but leaves at an unknown temperature. It is assumed that the Dean number may be ignored and the viscosity at the wall is 1.5 times greater than bulk viscosity. The other properties can be taken for water at 25C.
The agitator in the tank consists of three, 1m diameter concave radial turbines that operate at 84rpm or 1.4sec. The goal is to determine the outlet temperature of the cooling water and verify if the cooling water flow rate is sufficient. (i.e. Cooling water can not exceed 60C when returned to the cooling towers.)
a) Calculate the Nu number and hi for the cooling media side. (Half Jacket) Assume heat is only transferred through the straight wall side of the tank (i.e. heat transfer through the top and bottom of the tank can be ignored.)
b) Calculate the Nu number and h0 for the agitated side. (Assume the bulk viscosity is equal to the viscosity at the wall)
c) Assuming a fouling factor for treated cooling tower water, provided in the paper, calculate the overall heat transfer coefficient. (Assume the tank and jacket is constructed of stainless steel k=16.3Wm**K)
d) Solve for the outlet temperature of the cooling water and explain if the cooling capacity for the system is adequate. Why is there a limit to the return temperature on cooling water?
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