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.
Measuring efficiency of positive and negative ionic wind devices for comparison to fans and blowers
Abstract Many industries are pursuing alternate air moving devices to reduce the power consumption of their air cooled products. The literature suggests that ionic AMDs have low efficiency. The literature, however, does not define efficiency the same way the computer industry defines it for rotary AMDs. In this study, static efficiency of ionic AMDs was evaluated similar to rotary AMDs. Various emitter to collector distances and various ring lengths, were evaluated for positive and negative coronas. By controlling emitter to collector distance and collector length, efficiencies were obtained more reasonably compared to rotary devices.
Suppressed Light Emission of the Reaction Zone in Detonation
THE detonation of high explosives in water can be photographed with an open camera and a flash light as the explosive gases do not emit light. The method has been used1 to investigate the spread of shock waves and explosive gases, and to investigate the initiation by shock waves2. We have found that it can be used also in certain gases such as butane and propane. The method is not suitable, on the other hand, for explosives with two levels of detonation velocity in the case of low velocity. A great part of the reaction then occurs after the reaction zone has passed and the expanding explosive gases are very luminous even in water.