TY - JOUR
T1 - Thermal impact of integrated bore cooling with impinging jets and turbulators in rotating shaft of interior permanent magnet electric motor
AU - Woei Chang, Shyy
AU - Ling Cai, Wei
N1 - Publisher Copyright:
© 2024 Elsevier Ltd
PY - 2025/1
Y1 - 2025/1
N2 - Thermal failures limit power density of an electric motor and having effective cooling schemes is vital. The oversights in cooling of rotating components through compound heat transfer enhancement (HTE) methods led present study to devise novel shaft cooling schemes that integrate impinging-jets and turbulated annular-flows using pin-fins and spiral rib. The empirical correlations of cooling attributes and flow resistances in rotating shaft with three innovative cooling arrangements are devised for defining thermal boundary conditions during thermal simulations of an interior permanent magnet electric motor using the validated tridimensional model. With rotations, jets in shaft are distorted and diffused by Coriolis forces and crossflows, attenuating cooling efficacy over impinging-jet regime. Heat transfer elevations afforded by annular flows with turbulators in shaft with slow rotations are depressed by further increasing rotor speed until threshold speeds, above which the rotation-induced heat transfer deprivations are recovered. Turbulators in shaft augment flow resistances, reducing flow rates at constant pumping powers; but their HTE benefits still leverage overall cooling efficacies. The maximum coil (magnet) temperatures are reduced by 30.16–35.2% (69.73–75.7%) of those without shaft cooling at three sets of operating conditions with rotor speeds of 1000, 2000, and 3000 rev/min.
AB - Thermal failures limit power density of an electric motor and having effective cooling schemes is vital. The oversights in cooling of rotating components through compound heat transfer enhancement (HTE) methods led present study to devise novel shaft cooling schemes that integrate impinging-jets and turbulated annular-flows using pin-fins and spiral rib. The empirical correlations of cooling attributes and flow resistances in rotating shaft with three innovative cooling arrangements are devised for defining thermal boundary conditions during thermal simulations of an interior permanent magnet electric motor using the validated tridimensional model. With rotations, jets in shaft are distorted and diffused by Coriolis forces and crossflows, attenuating cooling efficacy over impinging-jet regime. Heat transfer elevations afforded by annular flows with turbulators in shaft with slow rotations are depressed by further increasing rotor speed until threshold speeds, above which the rotation-induced heat transfer deprivations are recovered. Turbulators in shaft augment flow resistances, reducing flow rates at constant pumping powers; but their HTE benefits still leverage overall cooling efficacies. The maximum coil (magnet) temperatures are reduced by 30.16–35.2% (69.73–75.7%) of those without shaft cooling at three sets of operating conditions with rotor speeds of 1000, 2000, and 3000 rev/min.
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U2 - 10.1016/j.tsep.2024.103164
DO - 10.1016/j.tsep.2024.103164
M3 - Article
AN - SCOPUS:85213212764
SN - 2451-9049
VL - 57
JO - Thermal Science and Engineering Progress
JF - Thermal Science and Engineering Progress
M1 - 103164
ER -