Process mode for the RR1 example simulation

The purpose of Process Mode is to set an initial transfer line configuration and provide an initial set of solution values for the transition to Fluid Flow mode. We configure the pipe sizes in Process mode in the direction of flow. We build the simulation by doing the following:

1. Specify the flow and estimate the starting pressure in the source models.

2. Add a pipe model, starting with HP1. Set an appropriate number of pipe segments (for example, 10). Specify the pipe length. Specify the pipe pressure drop so that the outlet approach to critical velocity (Mach) in the last pipe segment is around 80%. Set the pipe Size parameter such that D_margin is positive.

3. Repeat step 2 until you reach the vacuum column while adding mixers and pipe enlargers as necessary. Add a sink to represent the vacuum tower.

4. If the pressure at the vacuum column is not close to the design requirement (35 mmHg), modify the source pressure and the DP in each pipe until the pressure profile is close to the design requirements.

5. Take a Snapshot

It is not necessary to obtain a perfect solution in Process mode. The Process mode solution only needs to be close enough to the design requirements so that simulation successfully solves when you transition to Fluid Flow mode.

After going to Fluid Flow mode, you may find that you need to add more pipe enlargers to avoid critical flow. If this is the case, return to Process mode to add the enlargers and provide a new initial estimate.