| 摘要 |
A convection-cooled electromagnetic device, such as a transformer, and methods of cooling that utilize a ferrofluid as a cooling medium. The device's leakage magnetic field, which can be augmented by auxiliary magnets, draws the ferrofluid toward the device. As the fluid approaches the device its temperature rises, resulting in loss of magnetic properties and a decrease in density. The ferrofluid rises as its temperature approaches the Curie point, since the gravitational effect of density reduction begins to overcome the weakening magnetic attraction. Movement of hot ferrofluid is strongly assisted by the attraction exerted by the device on cooler, more intensely magnetic ferrofluid, which displaces the hot ferrofluid. The displaced ferrofluid cools as a result of movement from the heat source and through contact with the walls of the housing. Preferably, the Curie temperature of the ferrofluid is close to or slightly higher than the operating temperature of the device.
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