Study On DC Discharge And Gathered Characteristics Of Electric Mist Collector In Cooling Tower

This paper studies the micro discharge properties in EMC through numerical simulation. By comparing the temperature distribution and electron density distribution in different conditions, it gets the appropriate electrode geometry and power supply mode of EMC. These provide the theoretical support for the choice of electrode geometry and power supply mode in this paper. After that, based on the problem of severe water resources waste in cooling water, this paper uses a demist unit of EMC as research object by the means of numerical simulation and experiment to study demisting characteristic and electrical characteristic of EMC in point electrode and anode discharge conditions. This paper analyzes the influence of velocity, voltage and specific resistance on droplet quality concentration distribution, electric field distribution and collection efficiency. It also makes some comparisons and analysis on the electrical characteristic in EMC under DC voltage and AC voltage conditions. It reveals the influences of velocity and voltage on collection efficiency and current through high voltage experiment, and compares them with simulation results. By orthogonal test, it analyzes the primary and secondary role of velocity, voltage and specific resistance to collection efficiency, collection water and economic parameter ton degree ratio. The main conclusions of this paper are as follows.Plate electrode discharge has a higher electron temperature but the fullness degree of electron temperature is worse. Electron temperature is mainly concentrated near the discharge electrode under anode discharge, the discharge area is too narrow and most of the areas have a very low electron temperature, which leads to the effect that anode discharge is much worse than the cathode discharge. Aiming at the work of EMC, point electrode and anode discharge are preferably.Collection efficiency increases with DC voltage, but decreases with velocity and specific resistance, and droplet quality concentration decreases along the flow direction, and droplet concentration is much lower near the corona electrode.High voltage experiment shows that the critical coronal voltage and electrode current of AC voltage are lower than that of DC conditions, but the collection efficiency is higher than that of DC voltage. At the same time, the simulation results show that AC voltage function has higher maximum potential within EMC than that of DC voltage. While under the condition of AC voltage, outputting lower power makes higher potential within EMC. It can be concluded that compared with DC voltage, the AC voltage has higher economical efficiency. On the other hand, the sine voltage function's potential and electric-field intensity within EMC is higher than that of triangle voltage function. That is the economy of sine voltage function is higher than that of triangle voltage function.When the specific resistance is constant, the maximum value of ton degree ratio can reach at1.37t/(kW·h) when DC voltage is20000V and velocity is0.3m/s. It proves that blind increase DC voltage can not guarantee that the maximum return. Although changing the specific resistance of mist can improve the economic parameter effectively, it is very difficult to change the specific resistance. So it improves the economic performance always through changing the velocity and voltage.The experiment results are accorded with simulation results in the range of allowable error, which verify the correctness of the simulation results. The results of this paper can provide basic dates for system improvement of cooling tower and further study of demisting characteristics.