Open AccessCHARACTERIZATION OF HEAT CONDUCTIVITY OF ECCENTRICALLY ROTATING HEAT PIPES USED FOR COOLING OF MOTOR SPINDLES
Author(s) -
Berend Denkena,
Benjamin Bergmann,
Koji Kono,
Ryoji Ishiguro,
Heinrich Klemme
Publication year - 2021
Publication title -
mm science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.195
H-Index - 10
eISSN - 1805-0476
pISSN - 1803-1269
DOI - 10.17973/mmsj.2021_7_2021078
Subject(s) - thermal conductivity , heat pipe , materials science , heat exchanger , heat transfer , plate heat exchanger , plate fin heat exchanger , heat spreader , heat transfer coefficient , micro heat exchanger , mechanics , mechanical engineering , composite material , engineering , physics
Heat losses within motor spindles lead to undesired effects such as machining inaccuracies and de-creasing 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 de-veloped based on heat pipes with high thermal conductivity and fin-shaped heat exchangers. The de-sign and integration of these heat exchanger elements into a motor spindle is carried out using the fi-nite 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, un-known thermal characteristics of the heat transfer elements must be determined. In this paper, the de-termination of the thermal conductivity of the heat pipes is described. The determination of conductivi-ty 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 analyzed: 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 de-pending on the type of heat pipe.