Process mode for the U4 example simulation

The purpose of Process mode is to estimate the water flows required for the cooling duty in the individual heat exchangers and to check the pipe sizes. This helps determine an initial solution for the transition to Fluid Flow mode.

You can model Heat Exchangers by specifying three of the following four variables: heat duty, flow rate, pressure drop, or outlet temperature. We specify the heat duty, pressure drop, and outlet temperature. AVEVA Process Simulation calculates the required cooling water flow.

By specifying the heat exchanger duty, pressure drop, and outlet temperature, we develop a flow and heat balance that we can use to size the pipes. AVEVA Process Simulation automatically assumes that the Process mode flow rate and pressure drop is the reference flow and pressure drop unless you modify these values.

When we size the pipes, we can specify the maximum velocity as 3 m/s to determine the required diameter. Engineers need to pay attention to pipe sizes. The D_margin value should be positive in Process mode. Otherwise, the selected size may be too small.