Volcanic ash and aircraft safety

The study, led jointly by Dr Hongbiao Dong, Reader in Engineering Materials and expert in solidification (Department of Engineering), and Dr Mike Branney, an expert in explosive volcanoes in the Department of Geology, is about what happens when volcanic ash particles are heated in jet engines. It uses Thermal Analysis and X-ray Computed Tomography to analyse the temperature at which volcanic ash solidifies and melts.

The blades of aircraft engines operate at temperatures above their melting point and need a constant flow of cooling air blowing through tiny holes in the blades. The air floats onto the surface of the blades and forms a protective film that stops them reaching the same temperature as the combustion process of the engine.

Volcanic ash can reach a temperature of 2,000˚C in the engine, and will melt. If it is sucked into the tiny holes in engine blades the melted ash solidifies to a layer of glass and blocks the ventilation holes, and the engine will fail because the blades then melt.

Drs Dong and Branney are working with two contrasting types of volcanic ash, measuring their melting temperature in a Differential Scanning Calorimeter. They then study its morphology (structure) using X-ray Computed Tomography. The work is a new initiative that combines engineering and volcanology.

Volcanoes erupt frequently in Iceland and at other locations around the world, and the impact of ash on aviation can be considerable, depending on whether winds carry the ash across flight paths and airports.

The instrumentation used in this research is part of a new £1million hi-tech engineering centre, MaTIC, that works with industry to drive innovation in materials technology. The centre includes a range of advanced equipment for the understanding of materials behaviour.

Professor Sarah Hainsworth, who heads MaTIC, said: "MaTiC was initiated to bring together advanced techniques and equipment for studying a range of materials and materials problems, be they manufactured materials in components such as turbine blades or naturally occurring materials such as rocks, fossils, or in this case volcanic ash.

"It is investment in these types of equipment that have allowed the research into volcanic ash and flight safety to happen. It's the type of scientific techniques and application of expertise across the different academic disciplines that have allowed this research to go ahead. Research of this type allows us to develop greater insight into problems affecting industry."

An important concept of MaTIC is its interdisciplinary nature. Dr Hongbiao Dong said: "The establishment of this centre has encouraged us to collaborate across different areas of science and engineering and I hope exciting findings will emerge as a result of this interdisciplinary approach."