Building Pulp and Paper Stock Models in FluidFlow

Use this guide to build a pulp and paper stock network, select a stock friction-loss method, and review the calculated pressure drop, pressure profile, and pipe velocities.
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Required module: FluidFlow Slurry Module
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FluidFlow models Pulp / Paper stock as a distinct fluid type. Pressure loss is calculated using a hybrid framework that combines stock-specific correlations with conventional hydraulics. Beyond the applicable stock-correlation range, the solver reverts to the standard Darcy pressure-loss calculation as the contribution of pulp or fibers become insignificant.
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In the calculation options, select either TAPPI Technical Information Sheet (TIS) 408-4 or Moller K. Consider the oven-dry stock concentration and the stock data available for the selected method.

The TAPPI model is based on the observation that pulp stock pressure loss depends on concentration, velocity, temperature, and pipe geometry.

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Select the pulp type that represents the stock being modeled. TAPPI pulp types are stored in the database, which can be expanded when required. The selected type supplies the coefficients used by the correlation.
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The Moller method is more mechanistic than TAPPI and reflects how fiber suspension behavior depends on the physical characteristics of the stock. In this suspension-based hydraulic correlation, friction loss is shaped by fiber properties, concentration, temperature, and wall roughness, rather than by the empirical TAPPI power law alone.

Enter the stock's fiber aspect ratio and pulp freeness. Moller K uses these stock characteristics together with concentration, pipe roughness, temperature, velocity, and diameter to calculate pressure drop.
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Build the network using the same general workflow as a standard liquid model, including the required boundaries, pipes, and system components.

In the Input Editor of the inlet boundary:

Check that the concentration entered is consistent with the selected friction-loss method and its stated range.
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Calculate the network, then examine:

Interpret the results alongside the selected correlation, stock concentration, stock characteristics, and system information.

CSF refers to the freeness value obtained using the Canadian Standard Freeness method which expresses the time required to drain a specific volume of diluted pulp suspension.

Base it on the available data. Use TAPPI when your stock matches one of the pulp types stored in the database. Use Moller K when you have measured fiber aspect ratio and pulp freeness rather than a catalog match.
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TAPPI TIS 408-4 applies from 2–6% oven-dry concentration. Moller K applies over a wider range, 0.9–6%. Enter the concentration at the inlet boundary as weight % oven-dry and confirm it falls inside the range for the method selected.
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TAPPI pulp types are stored in a database that can be expanded when required. Alternatively, if you have measured fiber aspect ratio and freeness data, Moller K doesn't depend on a catalog match and may be the more direct method.
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Building a reliable pulp and paper stock model in FluidFlow comes down to matching the friction-loss method to the data on hand, keeping the oven-dry concentration inside that method's valid range. Both TAPPI TIS 408-4 and Moller K are hybrid correlations layered on top of conventional pipe hydraulics, so results stay traceable to standard Darcy behavior once the stock's fiber effects become small.
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Getting the method and concentration basis right means the pressure drop and pump duty calculated for a stock-transfer line reflect the furnish actually being pumped, rather than a generic liquid assumption that under- or overstates the real hydraulic load.​