Multi-Component Fluid Mixtures
Interacting VLE data (K values, activity coefficients, fugacities etc) is not currently stored or utilized in the flow calculations. For example, if you have a multi-component chemical mixture with more than one component changing phase at any point in the system FluidFlow makes an estimation of vapor phase composition based on ideality. Therefore the product may not be suitable for use where you have many components each changing phase as we flow through a system. Then again it actually may be, using simplifying assumptions, often each case should be individually considered when you have flows of complex mixtures. Primarily FluidFlow is a tool for designing and optimising flow systems rather than attempting to be a stand alone process simulator.
Also, we currently have no provision of catering for mass transfer between phases due to solubility of a gas for example. Similarly one could not make a mixture of say hydrogen chloride gas and water and expect to get the properties of hydrochloric acid.
Related Articles
Gas Mixtures
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Troubleshooting Modeling of Fluid Mixtures
A fluid mixture has been created in the Database and modeled in a single-pipe system as shown below. We can see that, when modeled, the results are suspect and we have a result of N/A for fluid phase state at the inlet and outlet of the pipe. This ...
Apparent Viscosity - Bingham Plastic Fluid.
The apparent viscosity for a bingham plastic non-Newtonian fluid is calculated based on the shear rate, shear stress, coeff of rigidity and yield stress data. The equation for apparent viscosity is: apparent viscosity = yield stress / (shear rate + ...
Power Law Non Newtonian Fluid Friction Loss & Pipe Roughness
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Static pressure below fluid vapor pressure or negative
This message is often indicative of a data-entry issue and every step should be taken to correct this issue in order to obtain more accurate results. This warning can occur for a number of reasons as follows: 1. When a data-entry error/omission has ...