NFX CFD
Overview
This video introduces the Moving Reference Frame (MRF) method to analyze airflow generated by a rotating electric fan. The example demonstrates how rotating-flow behavior can be approximated using a steady-state analysis without physically rotating the impeller geometry.
MRF Analysis Workflow
• Rotating Region Setup
A separate rotating fluid region is created around the fan, with the fan geometry represented as an empty cavity within the region. A rotational condition of 1000 RPM is applied to the rotating region and its wall so that they rotate in agreement.
• Moving Reference Frame (MRF) Method
Instead of physically rotating the impeller, the surrounding fluid region is treated as rotating at the specified speed. This allows the analysis to be performed as steady-state, unlike the Sliding Mesh method, which requires transient analysis to physically rotate the impeller.
• Flow Result Analysis
Velocity, pressure, and streamline distributions are reviewed to examine the airflow generated by the rotating fan at 1000 RPM.
The video also compares the MRF method with the Fan Boundary Condition. While MRF is used to examine the local flow field around a rotating fan, the Fan Boundary Condition represents the overall pressure effect of the fan without resolving its local flow field.
Download Example Files
MRF Analysis Workflow
• Rotating Region Setup
A separate rotating fluid region is created around the fan, with the fan geometry represented as an empty cavity within the region. A rotational condition of 1000 RPM is applied to the rotating region and its wall so that they rotate in agreement.
• Moving Reference Frame (MRF) Method
Instead of physically rotating the impeller, the surrounding fluid region is treated as rotating at the specified speed. This allows the analysis to be performed as steady-state, unlike the Sliding Mesh method, which requires transient analysis to physically rotate the impeller.
• Flow Result Analysis
Velocity, pressure, and streamline distributions are reviewed to examine the airflow generated by the rotating fan at 1000 RPM.
The video also compares the MRF method with the Fan Boundary Condition. While MRF is used to examine the local flow field around a rotating fan, the Fan Boundary Condition represents the overall pressure effect of the fan without resolving its local flow field.