Modeling of a xenon short arc lamp considering the behavior of tungsten vapour evaporated from electrodes

Abstract

The tungsten vapour produced from the electrodes during short arc lamp operation is transported by gas convection and then deposited on the inner quartz bulb wall to form a tungsten thin film, causing the wall to blacken. We have been able to consider important phenomena for the first time by developing a unified numerical simulation model incorporating relevant sub-models. These include the absorption of the radiant energy due to blackening of the lamp and the temporal variation in the lamp parameters. The validity of the numerical simulation model is first evaluated by comparison with experimental results. The basic characteristics of the lamp obtained using the model is found to be in good agreement with the experimental results and other research results. The influence of the bulb wall blackening is then examined. The temperature of the bulb is shown strongly affected by convective heat transfer from the hot gas, and the temperature rise of the bulb after blackening is found to be primarily governed by the absorption of the radiant energy by the tungsten thin film. Through the increase in the bulb temperature, the gas temperature in the bulb is also increased. This raises the operating pressure, which increases the stress on the bulb wall. Consequently, it is demonstrated that the probability of breakage gradually increases with time due to the blackening by tungsten vapour deposition.

Numerical Prediction of Influence of Gas Species on Gas Convective Pattern of Short Arc Lamp

“…In the present paper, we have used a unified numerical simulation model [15] to investigate the factors that affect the short arc lamp characteristics by changing gas species. The influence of the arc voltage, temperature and flow field, radiative efficiency and gas convective pattern and also the blackening location was compared for Xe, Kr and Ar gases and examined.…”

“…The structure of the model is the same as that of the Xe arc lamp used in the previous study [15], in which the model was validated However, those can be found in our previous work [15]. 31s 溶 接 学 会 論 文 集 第 38 巻(2020)第 2 号…”

“…This study showed that each property is greatly influenced not only by gas species but also by temperature and pressure. Moreover, a unified model, which self-consistently calculates various characteristics of the short arc lamp operated under air cooling, has been developed [14,15]. The computational domain consists of a single "electrode-gasbulb" region.…”

3D computational study of arc splitting during power interruption: the influence of metal vapor enhanced radiation on arc dynamics

“…The three components q (r, i), q (r, j) and q (r, k) can be calculated by equation (28). Thus, the radiation-induced energy source S R used in the energy equation in table 1 is:…”

“…The plasma bulk has been treated under local thermodynamic equilibrium (LTE) [9,27,28] since the temperature is high enough to allow high collision frequency between heavy particles and electrons. With continued progress being made in nonequilibrium modeling, the arc plasma has been modeled under both thermal nonequilibrium and chemical nonequilibrium [29][30][31][32].…”