Beetle Juice

Yeah, beetle juice. Turns out that the spray of the Bombardier Beetle’s toxic fluid may hold the key to new fuel-injection jet engines. I didn’t expect that.

A beetle’s chemical warfare against marauding ants, birds and frogs has provided the inspiration for a European effort to design more efficient fire extinguishers, reliable pharmaceutical sprays and fuel-injection engines.

The bombardier beetle’s toxic blasts of boiling-hot poison could even provide the impetus for mini rocket boosters to keep a spacecraft on the right trajectory, according to Andy McIntosh, a professor of thermodynamics and combustion theory at University of Leeds in the United Kingdom.

Science Daily explains the biology:

Quantities of hydroquinone and hydrogen peroxide gases build up in the beetle’s abdomen but, when necessary for defence, get mixed together in a connected ‘combustion chamber’ to produce toxic benzoquinone. This hot fluid is then fired off at force in the face of enemy predators.

The key to the beetle’s powerful defensive trick is in its combustion chamber’s inlet (or entry) and exit valves. The inlet valve opens to receive the chemicals, which begin to boil as soon as they meet, and closes when a sufficient amount of gas has been received.

As the gases react together, they generate heat and increase the pressure in the closed chamber. When the pressure reaches a critical point, the end of the exit valve is forced open and the hot fluid is ejected as a powerful burst of toxic steam in a process known as “flash evaporation”.

Once the gas is released, the exit valve closes, the inlet valve opens and the chamber fills again, preparing for the next venomous ejection.

Check out pictures of the process here.

The mechanism has been replicated by a research team at the School of Process, Environmental and Materials Engineering at Leeds University. They were able to spray distances of up to four meters and precisely control the size of the droplets.

In the short term, the technology appears to have the most promise for fire extinguishers and drug delivery tools (like inhalers). But more efficient fuel-injection car engines and, even, precise jet engines are possible in the future.

A species of beetle, that squirts its predators with a high-pressure spray of boiling liquid, could provide the key to significant improvements in aircraft engine design.

The bombardier beetle’s unique natural combustion technique is being studied to see if it can be copied for use in the aircraft industry.

Scientists studying the bombardier beetle’s jet-based defence mechanism hope it will help to solve a problem that can occasionally occur at high altitude – re-igniting a gas turbine aircraft engine which has cut out, when the outside air temperature is as low as minus 50 degrees Centigrade!

Due to start early next year, this innovative 3-year project at the University of Leeds is being funded by the Engineering and Physical Sciences Research Council (EPSRC).

The little bug has got my respect.

Matching all of the beetle’s natural talents could still be a mean feat. “If we can think of a mechanism, nature has already done it, and better,” Eisner said. He’s found, for example, that the beetle can discharge its toxic bursts more than 20 times in a row before depleting its glands. Not that such repeated blasts are usually necessary. “After firing once, he can walk through a crowd of ants, and they just literally part and let him pass,” he said.

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