Improving the Performance of an Aluminum Rotary Furnace using Numerical Simulation

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Abstract

Rotary aluminum furnace is used to recycle aluminum from scrap. This is a complex process and consists of many different phenomena such as aluminum smelting and burn-off, gas phase turbulent combustion and radiation in a rotary drum. In this research, a model is presented which divides the furnace into three zones, according to the distinct phenomenon happening in each zone. Thethreezones are refractory lining, combustion zone and melting zone. Only heat can be transferred through zones’ interfaces and no mass transfer is allowed. Numerical results indicated that molten aluminum is highly affected by furnace rotation and rotation has a significant effect on aluminum melting time. In addition, the rotational speed of 1.2rpm leads to the minimum melting time. The results also showed that radiation is the dominant heat transfer mechanism inside the furnace and 84% of the total heat flux received by melting zone is due to radiation. This portion of radiation heat transfer increases to 88.5% by increasing radiation emissivity of refractory lining from 0.7 to 0.85. As a result, the temperature of exhaust gases decreases which means better performance of the furnace.Therefore, the furnace operation time decreases by 20 minutes.

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