Conjugate heat transfer in fractal tree-like channels network heat sink for high-speed motorized spindle cooling

A novel fractal tree-like channels network heat sink in spindle's cooling sleeve is designed based on fractal theory. A three-dimensional thermal and hydrodynamic model for fractal tree-like channels net heat sink is developed. The heat transfer and pressure drop characteristics are numerically investigated, taking into consideration conjugate heat transfer in the channel walls. The traditional helical channel net heat sink is designed with the same convective heat transfer area and inlet geometric dimensions. The pressure drop, temperature uniformity and coefficient of performance of the fractal tree-shaped net heat sink are evaluated and compared with those of the traditional helical channel net heat sink. A conclusion is made that fractal tree-like channels net heat sink has lower pressure drop, more uniform temperature field distribution and larger coefficient of performance than that of the traditional helical channel net heat sink. Both heat sinks were fabricated on a steel bar. The conclusion is verified by the experiment. (C) 2015 Elsevier Ltd. All rights reserved.