Thermofluids
People
Dr Frank Beyrau, Dr Simos Evangelou, Professor Yannis Hardalupas, Dr Andy Heyes, Dr Raad Issa, Professor William Jones, Professor Peter Lindstedt, Dr Ricardo Martinez-Botas, Dr Fred Marquis, Dr Salvador Navarro-Martinez, Dr Stelios Rigopoulos, Professor Alex Taylor, Dr Berend Van Wachem and Dr Tamer Zaki
Research Activities
The division has, over four decades, an internationally leading record in pure and applied research into Combustion, Heat and Mass Transfer and Fluid Flow. It has well equipped, recently refurbished laboratories and, as a result of recent College funding, hosts an extensive range of laser sources and detectors and extensive computational facilities. Our research is undertaken using advanced optical instruments and computational flow modelling methods (CFD). The ability of the division to undertake combined experimental and computational modelling studies at a fundamental level is an important aspect of the division’s capabilities and is, perhaps, unique within the UK.
We are developing computational modelling techniques, including both Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES). DNS is applied in fundamental studies of transition from laminar to turbulent flow and to heat transfer in two-phase flows. In LES, needed for high Reynolds number flows, the large scale motions are computed directly while the influences of the unresolved fine sub-grid scale are modelled. The method is being applied to inert mixing problems, combusting flows and to multi-phase problems including atomisation. Applications include gas turbine combustors, internal combustion engines, and spray drying.
We also develop optical instrumentation, including both single point techniques (such as laser-, phase- and Shadow – Doppler anemometers for velocity and the simultaneous sizing of droplets and non-spherical particles in the tens to hundreds of micrometers as well as two-colour pyrometry for ignition studies) and planar measurements (such as particle image velocimetry, intensity- and interferometric- Laser Imaging Droplet Sizing Planar for measurements of particle/droplet size, velocity, flux and concentration, Laser Induced Fluorescence of species such as OH and fuel-tracers) with the ability to make high cadence rate measurements in either 3 spatial dimensions or in 2 spatial dimensions and in time. In addition, quantitative versions of techniques such as Flame Chemiluminescence and Schlieren have also been developed. The main focus of the experimental research is to combustion and two-phase flows with the techniques being applied to both fundamental studies and to Diesel, Otto and so-called HCCI cycle engines as well as to gas turbine combustors and model coal burners.
In the context of turbochargers, the section has research on the application of unsteady fluid mechanics, instrumentation development and computational methods. Previous experience of high-speed generators for small scale and distributed power generation has enabled the development of dynamometers for torque measurement of turbocharger turbines operating at high rotational speeds. The latter has made possible research into turbocharger turbines operating in pulsating flows, which are more typical of the exhaust flow characteristics than the steady flow on which designs are usually based. Advanced and novel technologies for energy efficient engines, such as exhaust energy recovery for downsized boosting of engines, are being developed as well as active flow control and electric turbo-assisted technologies. There is also expertise in electrification and downsizing of turbochargers, increasing the engine efficiency to reduce the size.
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