Thermal Effect on Mixing Problem Description

This project investigates the thermal effect of mixing Glycerin & Water-liquid. The study aims to determine the effect of applying heat flux on a Y-shape pipe. First, the problem is solved without any heat flux, and then a different heat flux is applied.

Geometry & Mesh

The 3D geometry is designed in Ansys Design Modeler. There are two inlets for water-liquid and glycerin. After getting in contact with each other, they interact 10-meter long pipe. In addition, the mesh grid is carried out using Ansys Meshing software.

CFD Simulation

Several assumptions have been considered, including:

• The simulation is Steady to capture fluid behavior in a steady-state manner.
• The pressure-based solver type was used due to the incompressibility of the working fluid.
• Gravitational acceleration effects were ignored.

The following table represents a summary of the solution:

Thermal Effect on Mixing Results

After the simulation, 2-dimensional contours of both volume fractions are extracted. Plus, a plot indicating the volume fraction of phase 1, which is water-liquid, through the centerline of the outlet, is shown below. Indeed, the viscosity of glycerin is highly dependent on temperature, as illustrated in Fig.3. Applying a heat flux on pipe walls increases the temperature and decreases the glycerin viscosity. As a result, it has less surface interaction (viscous forces) and resistance through water-liquid and causes better mixing (see Fig.4). The plot shows that by applying 30000-watt heat flux, the volume fraction of water liquid gets higher at each point which illustrates the presence of water where it was not before. Moreover, The contours show that, due to the low thermal conductivity of glycerin, the temperature of central points remains approximately constant. In other words, by using a highly conductive fluid, the impact of thermal conditions on mixing would be more impressive.