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In a dairy operation, milk at a flow rate of 250 L/h and a
Chapter , Problem 11.27(choose chapter or problem)
In a dairy operation, milk at a flow rate of 250 L/h and a cow-body temperature of 38.6C must be chilled to a safe-to-store temperature of 13C or less. Ground water at 10C is available at a flow rate of 0.72 m3 /h. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg K, respectively. (a) Determine the UA product of a counterflow heat exchanger required for the chilling process. Determine the length of the exchanger if the inner pipe has a 50-mm diameter and the overall heat transfer coefficient is U 1000 W/m2 K. (b) Determine the outlet temperature of the water. (c) Using the value of UA found in part (a), determine the milk outlet temperature if the water flow rate is doubled. What is the outlet temperature if the flow rate is halved?
Questions & Answers
QUESTION:
In a dairy operation, milk at a flow rate of 250 L/h and a cow-body temperature of 38.6C must be chilled to a safe-to-store temperature of 13C or less. Ground water at 10C is available at a flow rate of 0.72 m3 /h. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg K, respectively. (a) Determine the UA product of a counterflow heat exchanger required for the chilling process. Determine the length of the exchanger if the inner pipe has a 50-mm diameter and the overall heat transfer coefficient is U 1000 W/m2 K. (b) Determine the outlet temperature of the water. (c) Using the value of UA found in part (a), determine the milk outlet temperature if the water flow rate is doubled. What is the outlet temperature if the flow rate is halved?
ANSWER:Step 1 of 7
The following are the given data from the question.
Volumetric flow rate of milk,
The density of the milk,
Specific heat of milk,
Overall heat transfer coefficient, 
Outlet temperature of the water 
Inlet temperature of the water,
Consider the diagram of counter flow heat exchange,
