Newsletter 2015.12 Index
Theme : "Mechanical Engineering Congress, 2015 Japan (MECJ-15) Part 2"
Thermal physical properties, morphology and dynamic behaviors of magnetic fluids are tunable by externally imposing a magnetic field. Owing to the fact, energy conversion and control using the magnetic fluids have attracted extensive attention in the field of thermal mechanical engineering. In the present report, a magnetically-driven heat transport device using temperature-sensitive magnetic fluid is introduced as an advanced technology using the magnetic fluids. Temperature-sensitive magnetic fluid has the temperature-dependent magnetization, which means that the magnetization strongly dependents on its temperature in a room temperature range. Owning to the characteristics, the proposed device can operates the working fluid of the temperature-sensitive magnetic fluid by applying magnetic field and supplying heat on the fluid, and automatically transfers the heat as well (see Fig.1). This implies that no mechanical pumps are needed to operate the working fluid to transfer the heat. The obtained results show that the proposed device can transfer the heat with a long distance of approximately 6 m, and work well under the low temperature heat source of ~100 ℃. The device is able to automatically transfer the heat without any performance degradation, even when it is placed horizontally or under micro-gravity field. In order to applying the proposed device for CPU or LSI cooling, we designed a miniaturized magnetically-driven heat transport device which is composed of mini-sized circular tube with an inner diameter ofφ1.54 mm. The obtained experimental results show that the working fluid of temperature-sensitive magnetic fluid does circulate by its own driving force at the heating condition of ～31.7 kW/m2. This results implies that the feasibility of application of the temperature-sensitive magnetic fluid to a MEMS cooling device. Fig.2 shows that the prototype of MEMS magnetically-driven heat transport device which has the tree parallel micro passes with 0.8 mm×0.5 mm and its performance is under testing.
Magnetic fluids, Nanofluids, Energy conversion, Heat transfer, MEMS
Fig.1 Ideal model of magnetically-driven heat transport device using magnetic fluid
Fig.2 Prototype of MEMS magnetically-driven heat transport device with 0.8mm×0.5mm micro passes