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Fluctuating Flames

Publish: May 21, 2021

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  • Mitsutomo Hirota

    Other : Associate Professor, Faculty of Science and Technology, Muroran Institute of Technology

    ÎçÒ¹¾ç³¡ alumni. Specialization: Combustion Engineering

    Mitsutomo Hirota

    Other : Associate Professor, Faculty of Science and Technology, Muroran Institute of Technology

    ÎçÒ¹¾ç³¡ alumni. Specialization: Combustion Engineering

When you look at a lit candle, where do you focus? Usually, you see the glowing orange part and recognize it as a candle while feeling the overall fluctuation of the flame. However, I find myself looking not at this glowing part, but at the base of the flame, located between the glow and the candle wick. In fact, this base of the flame is very troublesome and important. Whether a fire burns well or is extinguished effectively is determined by the "mood" of this base.

The best way to manage the mood of the flame's base is through sound. That said, I don't mean beautiful music, but rather inaudible ultrasound. Try making a sound like "ah" or "oh" toward a candle flame. Doesn't the flame fluctuate minutely? If this voice is just right for the fire, it burns well; if it is not right at all, it goes out. Higher pitches work with pinpoint accuracy. My research proposes applying this as a control device to improve efficiency by making fire burn better inside combustors, or as a fire extinguishing method using ultrasound in places like operating rooms or space stations where normal fire extinguishers cannot be used.

These days, our lifestyles are dependent on electricity. Stoves are electric, lights are electric, and even fireplaces are sold as electric gadgets. Cigarettes are electronic. Candles and incense sticks for Buddhist altars are LED. Even cars and airplanes are shifting toward electricity. That is why when power is lost during a disaster like an earthquake, we feel great inconvenience and suddenly appreciate the value of fire. In people's hearts, the question of whether the root of life is electricity or fire fluctuates. Research on fire is evolving within this fluctuation.

The fleeting and beautiful glow of a sparkler. The countless tiny sparkles emitted from the base make you forget the passage of time. Fire soothes the human heart and makes life convenient, but it can also bring uncontrollable disasters. This duality is the mysterious part of fire. First, let's light a candle. You can lose yourself in philosophical thought, or think about it from an engineering perspective. Why not spend some quiet time while touching upon the mystery of the fluctuating flame? And when you extinguish the fire, instead of blowing it out, try putting it out with your own voice by saying "ah." However, make sure there are no people around. You wouldn't want to be thought of as a strange person shouting at a candle.

*Affiliations and titles are those at the time of publication.