Scheme: Industry Fellowship
Organisation: University of Leicester
Dates: Aug 2012-Aug 2015
Summary: Thermoacoustics is a relatively new interdisciplinary topic in science and engineering combining the fundamental areas of fluid mechanics, heat transfer and acoustics. It is broadly concerned with a direct conversion of heat into sound, or using intense sound to transport heat. When a porous solid body (stack/regenerator) is immersed in an intense acoustic wave, the cyclic expansion and compression of the gas, coupled with its movement, can cause localised cooling and heating of the solid body, producing large temperature differentials. In a reverse effect, a high temperature differential imposed along the solid leads to a spontaneous generation of an acoustic wave, a form of useful work that can be converted to electricity. These effects are utilised in thermoacoustic (TA) coolers and engines, respectively. There are clear technological and environmental benefits of TA systems. Firstly, their engineering complexity is significantly reduced: a TA engine is essentially a pressurised network of acoustic ducts with heat exchangers and stacks/regenerators – having no moving parts – which generates useful work. This is a major advantage in applications where frequent maintenance is not possible. Secondly, they are environmentally friendly: the working medium is usually an inert gas such as helium, neon, argon or xenon, or their mixtures; cheaper systems can use air. Finally, they are potentially low-cost due to their simplicity, low maintenance and use of inexpensive parts, materials and working media. Potential applications include heat pumps for domestic use or upgrading industrial waste heat; direct conversion of waste or geothermal heat or solar power into electricity; solar driven cooling and air conditioning; separation of gaseous isotopes used in medical imaging, tumour detection and radiotherapy; cheap electricity generators driven by gas/biomass combustion, to name but a few. Thermoacoustics is an exciting technology with clear benefits to the public at large.