Electric Field Effect on Nanofluid Considering Charge Density, CFD Simulation, ANSYS Fluent Training

Description

Description

A nanofluid is a fluid containing nanometer-sized particles called nanoparticles. Nanofluids have novel properties that make them potentially useful in many applications in heat transfer. They exhibit enhanced thermal conductivity and the convective heat transfer coefficient compared to the base fluid.

Knowledge of nanofluids’ rheological behavior is critical in deciding their suitability for convective heat transfer applications. The electro field has generated potential difference created by a shell of a tube and a wire inside the pipe. Shell has a higher potential, and wire acts as a negative pole, making particles move in directed against the electrodes.

In this case, an N-shaped curved pipe is used to model a cross-section of Cooling System pipes. A thin wire is placed in the middle of this pipe to apply an electromagnetic charge. Cool water enters the pipe at the inlet. There are hot walls in the parts of the pipe body with a temperature of 390 Kelvin.

The cold water exchanges heat with the walls, and the temperature increase at the outlet is monitored. Aluminum nanoparticles with a Charge Density of 23 were used to increase the heat transfer coefficient of the coolant liquid, and their behavior in the presence of an electromagnetic field was investigated. Finally, the data of both modes without particles and particles have been compared.

The present model in the 3-D domain of this simulation has been designed in ANSYS Design Modeler. Domain has an inlet, outlet, hot zone, and inner wall for wire inside and outer wall as pipe shell.

The meshing of this present model has been generated by ANSYS Meshing software. The mesh grid is unstructured; the total cell number is 2,966,928 elements and 720300 nodes. The figure below shows an overview of the performed mesh.

Methodology: Electric Field Effect on Nanofluid

In this simulation, the EHD Model with DPM Model has been used, which simulates the current created by the positive and negative poles to check the heat transfer from the walls, a fixed temperature of 390 k has been considered, and the temperature value in the scope and outlet is investigated.

The particles itself has been modeled with the DPM with Interaction with the Continuous Phase model as inert solid particles with a diameter of 0.00001m with a total flow rate of 1e-20 kg/s.

Also, the Energy Equation is On to capture the temperature.

Conclusion

In the two investigated cases, by comparing the contour of temperature and velocity with each other, it is clear that in the case with particles, it is spread more evenly, and the average temperature calculated in the range of temperature increase shows 0.1 Kelvin compared to the model without particles as can be seen in the following table.

On the other hand, the mean temperature at the outlet also shows an increase of 0.5 K in the model with electromagnetic field particles.

Also, the velocity contour shows that in the model used, nanoparticles affect the cooling fluid due to the presence of the magnetic field and the shaping of the particles, and the velocity field is more uniform.

	The average temperature in the domain	The average temperature at the outlet
With particle and electric field	310.43 k	316.59 k
Without particle and electric field	310.31 k	316.16 k