Archimedes Screw Turbine (AST) CFD Simulation

Archimedes Screw Turbine (AST), CFD Simulation, ANSYS Fluent Tutorial

Description

In this project, an Archimedes Screw Turbine (AST) consisting of 3 blades has been simulated. The simulation results have been investigated using ANSYS Fluent software. We perform this CFD project and investigate it by CFD analysis.

Archimedes Screw Generator, also known as Archimedes Screw Turbine (AST), or screw turbine, is a hydraulic machine that uses the principle of the Archimedean screw to convert the potential energy of flow on an upstream level into kinetic energy.

It is assumed that the turbine is set on a river and water fluid flows through it. There is a flow on the upper box of the domain at a fixed level. The turbine has a 30-degree angle with the ground while water enters the domain from the upper level. The gauge pressure in the outlet is zero, and all other faces are stationary walls.

The present model is designed in three dimensions using the Design Modeler software. There are two rectangular boxes at the turbine’s beginning and end, which guide the flow into the turbine, and finally, the water exit from it. The turbine’s interior and exterior radius is 0.5 m and 1 m, respectively.

This geometry has meshed in ANSYS Meshing software, and the number of them is more than 2 million elements.

Archimedes Screw Turbine Methodology

The preferred method for the rotational movement of the turbine is an unsteady Mesh Motion. Considering the conception of this method, (the Mesh Motion method), the rotating zone contains the Screw Turbine that rotates independently.

The VOF model is used to define the water and air phases. Also, the upper level of the domain contains water at a fixed level using the Open Channel Flow option.

The two-equation Standard k-epsilon model simulates the turbulence in the flow.

Archimedes Screw Turbine Conclusion

At the end of the solution process, two and three-dimensional contours and vectors related to water pressure and velocity are obtained. At first, water flow enters the upper box, passes over the turbine blades, and moves to the outlet face.

The output power of the turbine is calculated and its maximum amount for the angular velocity of 10 rpm is approximately equal to 5 kW. The Output power is equal to the Moment parameter obtained by ANSYS Fluent multiplied by the angular velocity of the turbine in radians per second which for this project is 1.05. The following figure shows the Moment parameter changes at different times of the solution.

Also, static pressure contour is obtained in the whole domain; as can be seen, it decreases while passing through the channel.