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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EFFECT OF HEAT TRANSFER ENHANCEMENT WITH JET COOLING BETWEEN OUTER AND SLOTTED INNER CYLINDERS IN AN ELECTRICAL ROTATING MACHINE

Get access (open in a dialog) DOI: 10.1615/IHTC16.ctm.023107
pages 3775-3780

Sinopsis

Toward the improvement of performance of the air-cooled generator, an appropriate design for the heat removal is important. An air-cooled generator is composed of the pair of coaxial cylinders with a fixed outer cylinder (stator) and a rotating inner cylinder (rotor), and the rotor is arranged axial slits to wind coils. The rotor and stator are cooled using the air jet gushing from axial slits. The present study experimentally and numerically clarifies the unsteady flow behaviors and heat transfer characteristics of jet cooling in the rotating coaxial cylinders mimicked a salient-pole rotor within the air-cooled generator. The test section of experimental apparatus was made of acrylic to observe the flow behavior, and the rotating of rotor and jet flow was simultaneously performed in the test section. The heat transfer coefficient between the rotor and stator were obtained by the numerical simulation performed with OpenFOAM. In the flow visualization, when the jet flow rate and rotating speed were varied, two flow patterns were observed in the slit; one of the flow pattern was the flow that the jet dominated, and the other pattern was the vortex that rotates in the slit. In the numerical simulation, the same flow patterns as flow visualization were identified. It was confirmed that the local Nusselt number on the back-side wall in the rotating direction was higher than that on the front-side wall. It was confirmed that the Nusselt number change depending on jet Reynolds number, and the cooling performance can improve by the jet cooling.