An Experimental Investigation to Study Temperature Distribution and Thermal Transfer in a Crucible Furnace with Oscillating Combustion

Oscillating combustion is gaining importance these days. Several researchers are studying on the effects of oscillations in combustion in enhancing heat transfer rate, temperature distribution in the furnace load and reduction in emissions. Different kinds of oscillating mechanism to create oscillations in the combustion were used in the research. Oscillating valves such as electrostrictive actuator, cyclic valve, solenoid valve or a solenoid-based EGR valve, rotary plug valve were used to study the combustion. Recently, GTI Laboratories, and Air Liquide of Chicago research center have used Ceramphysics SSP valves. These valves due to electrostrictive properties produce changes in thickness of elostomers which produce cyclic changes in the gas flow area.

The author reports in this paper an oscillating devise developed and used by him in the combustion process for melting aluminum metal in oil fired crucible furnace which is of importance to foundry. A cam operated valve was used to cause oscillations on the fuel flow. Experiments have been conducted to study the effect of varying amplitudes, frequencies, loads and air-fuel ratios and compared the results of oscillating combustion to the conventional nonoscillating combustion. The oscillating combustion resulted in low melting time, low specific energy consumption, increased heat transfer and enhanced furnace efficiency as well as reduced flue gas emissions. Temperature distribution inside the furnace and heat transfer from hot gases to loads during oscillating of combustion mode plays important role in achieving these results. The reasons for such improvements are discussed in this paper.