Polarity Effect and Flow Characteristics of Wire-Rod Type Electrohydrodynamic Gas Pump
The electrohydrodynamic (EHD) flow characteristics for a wire to rod type EHD gas pump have been experimentally investigated. Experiments were conducted for DC negative and positive applied high voltage to a corona wire of diameter 0.24 mm from 0-24 kV, grounding rod electrode diameter from 1.5 mm to 3.1 mm and wire/rod electrode distance to pipe diameter ratio from 0.63 to 1.16. It was observed that the polarity plays an important role, where a negative high voltage generates a higher gas flow than that of a positive polarity. The results show that a maximum of 40 L/min of gas flow rate is generated at 0.37 W energy input when the pipe diameter is 20 mm with the corona wire electrode and grounding rod electrode gap distant set to 12.6 mm under negative applied voltage compared to 25 L/min at 0.23 W energy input for the positive case at the same specific energy density.
Electrohydrodynamically enhanced capillary evaporator
A two-phase capillary evaporator has been enhanced using electrohydrodynamic (EHD) forces. The evaporator was experimentally investigated under DC applied electric field operating modes as well as without an applied electric field. The results without the applied EHD forces show that the induced flow increases with increasing applied heat loads until a dry out condition is reached. The applied DC voltage electric field provides flow enhancements as high as 200%. A slight polarity effect was observed.
Actuating Principle of Online Automatic Balancer with Counter Weight Driven by Magnetic Force
Kinematic precept of mass block in automatic balancer is proposed following the principle of online automatic dynamic balancing.By combination of electromagnet and permanent magnet,the magnetic circuit of the balancer with ring coil and rare earth permanent magnet is designed.Actuating process of the balancer is discussed and then a step drive voltage waveform is defined.For the high-speed grinding motorized spindle 170MD12Y16,the mechanical structure and dimensions of the balancer are schemed out.The electromagnetic simulations for the designed balancer are conducted and the better coil ampere-turns and reluctance adjusting ring thickness are then determined.The validity of simulation results is verified by a balancer driving experiment and the desired voltage value and its duration time are also determined.the designed balancer has a stable operation process without out-of-step and fluctuation around balanced position when the ampere-turns are considered as 1 kA,the reluctance adjusting ring thickness 0.2 mm,the driving voltage 12.4 V and the voltage duration time 120 ms.