Description

High-Bypass Turbofan Engine (Fan Section) Simulation, ANSYS Fluent CFD Training

Description

The turbofan or fanjet is a type of air-breathing jet engine widely used in aircraft propulsion.

In a turbofan, some of that air bypasses these components. A turbofan, thus, can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust. Engines that use more jet thrust relative to fan thrust are known as low-bypass turbofans. Conversely, those with considerably more fan thrust than jet thrust are known as high-bypass.

Most commercial aviation jet engines in use today are of the high-bypass type. The fan flow has lower exhaust velocity, giving much more thrust per unit energy (lower specific thrust). Both airstreams contribute to the gross thrust of the engine. The additional air for the bypass stream increases the ram drag in the air intake stream-tube

The ge9x turbofan engine fan, a high-bypass engine, has been modeled in this case. The gas-turbine section has not been considered to study bypass flow behavior and model the fan at working condition. This simulation show airflow created by the fan in high-bypass and engine core at a Mach Number of 0.8.

The present model in the 3-D domain of this simulation has been designed in ANSYS Design Modeler. The domain contains a velocity inlet, pressure outlet, and wall for the intake wall and side for the far field.

The meshing of this present model has been generated by ANSYS Meshing software. The mesh grid is unstructured; the total cell number is 16,635,982 elements.

Methodology: High-Bypass Turbofan Engine Fan Section Simulation

For modeling turbulence, the k-omega SST model was used, which simulates the intake at the operational point with a velocity of 0.8 mach number.

Also, the MRF method is used to define turbofan rotation.

Conclusion

According to the speed contour in the middle of the engine, this simulation shows how the flow speed changes in different body profiles. At first, after the fan, the flow enters the bypass section and its speed increases, and finally, after passing through the bottleneck at the outlet, it reaches its maximum speed.

After passing through the fan, the core current of the engine increases and reaches its maximum in the combustion chamber, then when it reaches the turbine, its speed decreases, and it exits the outlet at a lower speed. These two outflows are mixed and reach a speed almost equal to the input speed

The temperature contour indicates the overall temperature increase in the engine environment. This increase in temperature is due to the increase in pressure due to the movement of the vanes, which is also noticeable in the static pressure contour.

The pressure contour is also due to increased pressure in front of the fan and bypass channels. Therefore, by summarizing these three diagrams, you can get a good view of how the fan works in a turbofan engine