Feasibility study of electromagnetic driven dream pipe

Dream pipes, a kind of forced oscillatory heat pipes, necessarily require some driving mechanisms for oscillations of enclosed working fluids. Commonly fitted up are mechanical shakers but not suited for practical use because of becoming quite large in volume. Proposed in this study is an innovative type of dream pipe with an electromagnetically actuated oscillating disk. The driving principle basically follows Lorentz force generated upon electric wires set on the disk, in the radial direction of which a periodically varying magnetic field is formed by applying the three-phase alternating current. Feasibilities of this new device are theoretically examined by analyses from both thermal and electrical points of view. Heat transfer analysis is first made to determine the required driving force, from which the tidal displacement of the fluids is derived to show a resulted possible oscillation amplitude. Joule heat minimization analysis is then made to specify a suitable couple of the applied direct and alternating current voltages. Such specified voltages may go down to a lowest level by selecting the driving frequency to become an intrinsic one. The specific power, defined as the power to heat ratio, is introduced as a performance index of that device. Numerical results show that less specific power than 0.10 is possible in most of supposed design cases and that the required magnetic flux density is far smaller than 0.5 T. It is thus concluded that the electromagnetic driven dream pipe is realizable. A 400 W m class dream pipe of electromagnetic drive is then design-specified as a demonstrative example.