Wind Tower (2-D) CFD Simulation Tutorial

Description of Conjugate Heat Transfer in Wind Tower

Project Overview

Using ANSYS Fluent software, this study investigates the conjugate heat transfer (CHT) process of airflow inside a simplified four-story wind tower.  By means of CFD study, we investigate the interaction of convective and conductive heat transport inside this architectural component intended for natural ventilation.

Geometry and Meshing

Model Design

Design Modeler is used to carefully create the 2D shape of the wind tower, hence capturing the necessary characteristics for heat transfer study.

Meshing Details

The computational grid is generated using ANSYS Meshing software, featuring a structured mesh with 6,375 elements to facilitate accurate simulation of heat and flow dynamics.

Wind Tower Methodology

Heat Transfer Modeling

Conjugate heat transfer modeling consists of both convective and conductive heat transfer mechanisms inside the wind tower.  With a heat generation rate of 1000 W/m³, the diagonal wall on the right side of the computational domain is kept at 305 K.

Inlet Conditions and Airflow

• Inlet Boundary: Top left side of the wind tower
• Inlet Velocity: 12 m/s
• Initial Temperature: 300 K

Aiming to promote ventilation and temperature lowering, air flows through the four stories of the structure.

Gravity and Buoyancy Effects

Gravity is activated in the Y direction to mimic natural convection.  With an initial air density of 1.225 Kg/m³ and a thermal expansion coefficient of 0.00331 1/K, the Boussinesq model is used to account for changes in air density caused by temperature variations.

Results and Conclusion

Two-dimensional contours connected to velocity, pressure, temperature, streamlines, and velocity vectors inside the computational domain help the simulation to uncover various important discoveries.

Temperature Distribution

The temperature contour showcases the thermal distribution along the heated wall, illustrating how temperature varies throughout the wind tower.

Airflow Dynamics

Contours of velocity, streamlines, and velocity vectors reveal that:

• Top Levels: Experience higher momentum and velocity airflow due to reduced hydraulic resistance.
• Bottom Levels: Display rotating airflow patterns induced by the forced airflow, as seen in the velocity vector contour.

Driven by the natural convection effect started by contact with the diagonal heated wall, the airflow finally rises to depart through the pressure outlet boundary on the top right.