Process mode for the U5 example simulation

The purpose of Process mode is to determine minimum new pipe size requirements at increased network flow requirements. For existing systems such as this, we also use Process mode to generate an initial solved solution in preparation for switching to Fluid Flow mode.

We specify the fire water supply (SRC1) temperature and pressure and the delivery flows (SNK models) with values as mentioned in Process description for the U5 example simulation.

AVEVA Process Simulation uses a summation of the individual hydrant flows to calculate the split ratios for all network splitter models except SP1. We assume that the SP1 splitter model has a 50% flow split for the ring network. This creates a pressure imbalance, which shows in the Pslack variable in the MX1 model. AVEVA Process Simulation calculates the pressure in mixer MX1 as the minimum of inlet stream pressures.

For new designs, we specify the pipes with their equivalent length and elevation change based on planned plant layout and assumed pipe velocities of 3 m/s. We select the pipe diameter by ensuring that D_margin is greater than 0 mm. For existing designs, we can still use Process mode with existing pipe sizes to generate an initial solved solution, even if some pipes are undersized for an assumed 3 m/s pipe velocity.

The following table provides the details of the newly added pipes required to provide fire water to the new delivery points, SNK5 and SNK6.