SSHEATEX - Steady-State, Two-Pass Heat Exchanger

2 SSHEATEX - Steady-State, Two-Pass Heat Exchanger 

A purified water stream for a food processing plant is raised to required temperature by heat exchange with warm untreated process water. A conventional two-pass heat exchanger is to be used. This problem is based on the formulation of Walas (1991) and data taken from Backhurst, Harker and Porter (1974). 

In the first pass, both the hot and cold fluids flow in cocurrent flow through the heat exchanger, whereas in the second pass, the cold fluid now flows countercurrent to the hot shellside fluid. Half the heat exchange area is therefore in cocurrent flow and half in countercurrent flow. 

For the cold side fluid in forward cocurrent flow 

For a given inlet and outlet cold water temperature, the outlet hot water temperature is determined by an overall heat balance where 

The derivation of the model equations follows that of Sec. 4.5.2.1. For the hot shellside fluid 

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