Research on the Cooling System of High-Speed Motorized Spindle

In order to control effectively the temperature of the motorized spindle, based on thermodynamics, heat transfer theory and fluid dynamics control theory, the model of motorized spindle with cooling system is established and simulated. Based on the idea of orthogonal experiment and simulation experiment, the comprehensive tests are built, and the optimum matching relation between the heat flux of motor and the flow velocity of cooling liquid is determined in this article. The results show that the flow velocity of coolant can be adjusted according to the heat flux of motor which can control the temperature in the steady range and improves the cooling effect.

Analysis and Verifications for Meso-Scale Heat Exchanger With Magneto-Hydrodynamic (MHD) Pumps

Electronic devices have been mainly relying on passive heat exchangers to transfer heat away for preventing catastrophic thermal runaway. However, the passive heat exchangers usually provide limited cooling capacity due to spatial limitations of the target systems. In this paper, an active heat exchanging system, based upon MHD pumping principle for driving electrically conducting coolant without utilizing mechanical moving-parts, was studied and experimentally verified. Governing equations of electrically conducting liquids driven by the Lorentz forces were derived by assuming steady state, incompressible and fully developed laminar flow conditions. Furthermore, numerical simulations were conducted with the explicit Finite-Difference Method to evaluate the performance of the heat exchanger. Finally, an experimental apparatus was built for measuring the flow velocity of coolant and the associated total cooling capacity. A significant flow velocity of 1.09 × 102 mm/s at 3 Ampere applied current was observed when the magnetic flux density was kept at 0.4 Tesla. The experimental results concluded that the heat exchanger consumed very low electric power; hence, the cooling system is very promising for applications in micro-fluidic systems.