Characteristics of Multi-Phase Alternating Current Arc for Glass In-Flight Melting

Abstract

An innovative in-flight melting technology with multi-phase AC arc was developed for glass industry. The enthalpy probe and high speed video camera were used to characterize the temperature, velocity, and discharge behavior of multi-phase AC arc. The effects of input power and sheath gas flow rate on arc and melting behavior were investigated. Results show that the temperature and velocity on arc center are increased with input power or sheath gas flow increase. The fluctuation of luminance area ratio and coefficient of variation reflects the change of arc discharge behavior. High temperature of plasma enhances the melting of granulated raw particles during in-flight heating treatment. The shrinkage of particle and the volatilization degree of Na 2 O increase under a larger flow rate of sheath gas. The characterized arc behavior agrees with the melting behavior of glass raw materials, which can provide valuable guidelines for the process control of glass melting.

Characteristics of non-thermal AC arcs in multi-arc generator*

“…The properties of the multi-arc discharge, such as discharge area, fluctuation, and arc rotation velocity were investigated by data processing of the arc discharge image. The digital image processing technique [26,27] was used to calculate the discharge area. The image correlation analysis method was employed to determine the arc rotation velocity.…”

“…Here, the parameter of the luminance ratio with different observing zone chosen was in-troduced to investigate the arc spatial distribution in the discharge zone, which is based on an assumption that the highbrightness region can be regard as arc covered or high temperature zone. [26,27] By analyzing and processing the discharge image, the parameters were obtained and the detail procedures are listed as follows:…”

“…It can be clearly seen that there were evident fluctuations of TR-LAR for all four electrode configurations, and the amplitudes of these fluctuations all decreased with the 125205-7 increase of diameter of the observing zones. Since the highbrightness region can be assumed as arc covered or high temperature zone, [26,27] the fluctuation of TR-LAR indicated the fluctuation of average temperature in the observing zone or instability of arc sweeping through the observing zone. Moreover, the smaller the observing zone diameter was, the greater the differences among the TR-LAR of the four electrode configurations were, which implied that the arc plasma exhibited obviously different dynamic behaviors in the central area of the discharge zone.…”

Characteristics of DC arcs in a multi-arc generator and their application in the spheroidization of SiO2 *

“…The region covered by arc plasma or high temperature can be represented by the luminance area of discharge image. [20,21] To obtain the luminance area, the processing method refers to the literature, [34][35][36] which was derived from averaging the successive multiple discharge images at each pixel. The number of discharge image processed was selected as 3000 and 10000, whose time scale was around sub-millisecond.…”

“…The spatial fluctuation of arc plasma distribution is an important parameter evaluating the application potential of arc plasma. By means of standard deviation analysis on the discharge image, [34][35][36] figure 9 presents the standard deviation of spatial distribution of arc discharge in AD and OP patterns for different numbers of processed frame images. The fluctuation degrees of arc spatial distribution both in AD and OP patterns were relatively smaller in the center of discharge zone.…”