KR408: How to calculate/report torque acting on a rotor's shaft using a UDF? (Solution ID: 917)
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Torque acting on a shaft is always an important quantity user often wants to calculate and monitor from a simulation. Fluent post processing REPORT panel allows users to report moment of the face acting on a face around a specified point. If a shaft is aligned with any of the X, Y or Z coordinates, then the torque acting on the shaft will be the same as the moment reported for the aligned axis. If the shaft is not aligned with any coordinates, user has to do some hand calculations. First, user must choose a moment center (any point that axis of the shaft passes through), then calculate torque using dot product of two vectors (the moment vector reported in the fluent console window and the shaft directional vector). For many pump applications, as rotor rotates, the opening of the flow passage is changing as well. As a result, flow rate, torque and force acting on a rotor will change with time. During unsteady simulations, user often wants to monitor torque and force, and want to save such information in a file for future post processing. For such purpose, if the shaft is aligned with any coordinates, user can use Solve/Monitor/Force Monitor panel to monitor or save force or moment. For each force or moment, user has to define a separate monitor. If shaft is not aligned with coordinates or user wants to extract all force/moment information into a data file for any future use, the following UDF can be used: |
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