TY - JOUR

T1 - Characterization of heat conductivity of eccentrically rotating heat pipes used for cooling of motor spindles

AU - Denkena, B.

AU - Bergmann, B.

AU - Kono, K.

AU - Ishiguro, R.

AU - Klemme, H.

PY - 2021/7

Y1 - 2021/7

N2 - Heat losses within motor spindles lead to undesired effects such as machining inaccuracies and decreas-ing lifetime of the motor and bearings. To reduce thermal loads, complex shaft cooling concepts with costly sealing techniques exist. For this reason, a novel, less costly cooling concept has been developed based on heat pipes with high thermal conductivity and fin-shaped heat exchangers. The design and integration of these heat exchanger elements into a motor spindle is carried out using the finite element method. The aim is to optimize the efficiency of the heat pipes and heat exchangers for optimal shaft cooling performance. For a simulation-based development of a prototype spindle, unknown thermal characteristics of the heat transfer elements must be determined. In this paper, the determination of the thermal conductivity of the heat pipes is described. The determination of conductivity is done experimentally. First, the developed test rig and the applied procedure for the determination of the conductivity are shown. Subsequently, the experimental results are presented and discussed. Two types of heat pipes were an-alyzed: Copper heat pipes with sintered wick structure and nickel-plated copper heat pipes with axial grooves. The influences of rotational speed, heat flow rates and the angle between the heat pipe and main axis of rotation were investigated. The results indicate a distinct dependency of the conductivity on the varied parameters. However, changes of parameter values have very different quantitative and qualitative effects on the determined conductivities depending on the type of heat pipe.

AB - Heat losses within motor spindles lead to undesired effects such as machining inaccuracies and decreas-ing lifetime of the motor and bearings. To reduce thermal loads, complex shaft cooling concepts with costly sealing techniques exist. For this reason, a novel, less costly cooling concept has been developed based on heat pipes with high thermal conductivity and fin-shaped heat exchangers. The design and integration of these heat exchanger elements into a motor spindle is carried out using the finite element method. The aim is to optimize the efficiency of the heat pipes and heat exchangers for optimal shaft cooling performance. For a simulation-based development of a prototype spindle, unknown thermal characteristics of the heat transfer elements must be determined. In this paper, the determination of the thermal conductivity of the heat pipes is described. The determination of conductivity is done experimentally. First, the developed test rig and the applied procedure for the determination of the conductivity are shown. Subsequently, the experimental results are presented and discussed. Two types of heat pipes were an-alyzed: Copper heat pipes with sintered wick structure and nickel-plated copper heat pipes with axial grooves. The influences of rotational speed, heat flow rates and the angle between the heat pipe and main axis of rotation were investigated. The results indicate a distinct dependency of the conductivity on the varied parameters. However, changes of parameter values have very different quantitative and qualitative effects on the determined conductivities depending on the type of heat pipe.

KW - Eccentric rotation

KW - Heat pipe

KW - Spindle cooling

KW - Thermal conductivity

UR - http://www.scopus.com/inward/record.url?scp=85109935167&partnerID=8YFLogxK

U2 - 10.17973/MMSJ.2021_7_2021078

DO - 10.17973/MMSJ.2021_7_2021078

M3 - Article

AN - SCOPUS:85109935167

VL - 2021

SP - 4698

EP - 4705

JO - MM Science Journal

JF - MM Science Journal

SN - 1803-1269

IS - Special Issue on ICTIMT2021

ER -