Search

The performance of electrostatic precipitators has been predicted by the Deutsch equation and its modifications over a long period, and ESP index is a good tool among them which considers the importance of electrical discharge. The present work shows the theoretical development of ESP index and the relevant model. The collection process considering migration induced by both electrostatic attraction and deposition is simulated. Subsequently, the model is applied to calculate grade collection efficiency for particles larger than 0.02 μm in electrostatic precipitators. The physical meaning of two coefficients, α (relative to particle charging and migration) and β (relative to particle deposition) in the model is clarified. By integrating and averaging the α and β values, the overall collection efficiency is obtained. The present predictions agree well with experimental data. The model is also able to predict variations of particle collection at different gas temperature. The particle mass emissions at the ESP outlets decrease linearly with the ESP index or its square root. It is expected that the present model can facilitate the design and sizing of the ESPs.

Cold atmospheric plasma jet (CAPJ) is widely used in many fields due to the reactive oxygen species (ROS) and low temperature for heat sensitive products. This paper presents inactivation of bacteria via a pulsed plasma jet with He/O2 mixed gas. To evaluate the disinfection performance, Staphylococcus aureus was used as indicator bacteria for experiments. When the plasma jet dealt with agar plates spraying bacteria, it was found that mixed gas has a better performance than pure inert gas, indicated by disinfection area. The increment of oxygen gas addition had benefit to disinfection ability of plasma jet, while the gas had an opposite effect on jet production in length. The experiments showed the efficacy of Staphylococcus aureus disinfection could reach up to 99.47% via helium/oxygen (2%) plasma jet.

For using multi-switches in parallel, external forced trigger is usually required to synchronize all of them. This paper describes a generator with 20 spark-gap switches without using external triggers. The generator mainly consists of a 20-stage transmission line transformer (TLT), 20 energy storage capacitors, and 20 high-pressure spark-gap switches. At the input side of the TLT, all switches, capacitors and TLT cables are inter-connected to synchronize them automatically. All switches are made of three electrodes and are assembled in one 2 bar compact chamber. The TLT consists of 100 RG218 cables. The capacitors are charged up to 50 kV during 20–50 µs with a total energy per pulse of 140 J. As a result, the output peak power is estimated to be about 5 GW. At the output side of the TLT, a variety of output options are possible. For the present design, output peak voltage, current and impendence are in the range of 50–250 kV, 1–50 kA and 1–250 Ω, respectively. Up to 100 independent simultaneous outputs can also be realized under the same peak power.