Abstract
The present study reports a numerical heat transfer approach, an effort devoted to defining a cooling concept for a high performance synchronous motor that has a High Temperature Superconductor (HTS) field winding. A lumped-circuit approach and a numerical, FEM analysis of a 500 kW HTS motor with an axial cooling channel is demonstrated in the report presented here. The thermal analysis performed using equivalent, lumped thermal network shows a simplified circuit which is aimed at delivering fast, design class results that can be solved analytically and also more complex schemes which are aimed at assessing variable regimes are solved numerically by a circuit simulator (QUCS). Both approaches are valuable, and complement each other in the quest for a meaningful preliminary design.
There are several difficulties related to standard lumped thermal circuit models such as concentrated heat sources, lack of detailed thermal load information, etc., and all these drawbacks can be overcome by a more detailed convection and conduction heat transfer model which are conveniently solved by numerical analysis, e.g. by FEM technique using FLUENT package. Various models that were implemented using the FEM technique include different coolants and a fin model. The coolants that were used in the present study are air and water. The maximum temperature attained in the stator for air and water is 382 K and 345 K respectively for limiting Reynolds number for laminar flow. Another approach to cool the motor is by attaching a fin of copper material in the cooling channel. This fin can be used as an alternative for water as it also bring down the maximum temperature in the motor to 350 K.
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