Mixing of Carbon Dioxide and Ethanol CFD Simulation

Description

Mixing of Carbon Dioxide and Ethanol (VOF) CFD Simulation, ANSYS Fluent Tutorial

The present problem simulates mixing two substances, including carbon dioxide and ethanol, in a rectangular tank by ANSYS Fluent software. We perform this CFD project and investigate it by CFD analysis.

The present model is designed in three dimensions using Design Modeler software. The present model consists of a vertical rectangular tank for mixing materials with dimensions of 0.06 m * 0.3 m, which has an inlet section at the bottom with a width of 0.002 m.

The meshing of the model has been done using ANSYS Meshing software. The mesh type used for this geometry is Structured, and the element number is 73788.

Also, the transient solver is enabled due to the nature of the problem, which is to investigate changes in the volume fraction of the mentioned phases.

Mixing Methodology

The VOF multiphase model has been used to simulate the two phases of carbon dioxide and ethanol in the present model. The constituents of this process include carbon dioxide with a molecular weight of 44.00995 kg/kmol and ethanol with a molecular weight of 28.966 kg/kmol.

The input flow enters the tank from the lower part with a temperature of 300 K. The inlet flow pressure is variable and time-dependent. For this purpose, the pressure inlet boundary condition at the input boundary is used, which has a UDF in the form 8000000 + 66666.666 * t.

Also, the temperature of the entering flow is set to 300K. This simulation process was performed in 180 s with a time step of 0.5 s. Furthermore, the standard k-epsilon model and energy equation are used to solve the turbulent fluid equations and calculate temperature distribution within the domain.

Mixing Conclusion

At the end of the solution process, two-dimensional contours of temperature, pressure, velocity, and volume fraction for each phase are obtained.

These contours are obtained at the last second of the simulation process interval. For instance, as seen in ethanol volume fraction and velocity contours, a secondary flow will form within the domain and cause the mixing process.