Pearls of wisdom to the next generation of combustion engineersFrom the IFRF Office
Contributed by Philip Sharman
Sheffield, Monday 11th June 2018
Professor Jim Swithenbank, Emeritus Professor at the University of Sheffield, co-author of the ANSYS Fluent computational fluid dynamics (CFD) code and former IFRF Superintendent of Research took the opportunity of his after-dinner speech at the IFRF 2018 Conference ‘Gala Dinner’ at the Magna Science Adventure Centre, to both reminisce about his time working for IFRF and to offer some very sound advice to the next generation of combustion engineers and scientists…
“My recollections of IJmuiden days of IFRF must start with some comments on my situation at that time. My childhood ambitions were in aircraft flight, hence my first degree was in Nuclear Physics at the University of Birmingham since this technology appeared to offer great range for nuclear powered aircraft, and several aero-engine companies already had groups investigating the potential designs. However, due to military service regulations, I worked for five years at Bristol/Rolls-Royce on the Bloodhound guided missile using supersonic ramjet propulsion. There I learned supersonic fluid dynamics which could also be used for subsonic flow by simply deleting higher order terms from the equations. I also found that we could not solve by hand all the simultaneous equations for: scramjet engine thrust, vehicle aerodynamics, flight trajectory, meteorology effects, radar guidance and target manoeuvres. However, by using the first ‘electronic brain’, then being developed at the English Electric factory, allowed me to successfully predict the homing performance of the guided missile. Hence, I have been devoted to computers ever since 1952.
My next job – for four years – was to develop hypersonic scramjets at McGill University in Canada and these have now flown at Mach 9. However, there is little commercial need for them as they cannot be used at the orbital speed of Mach 25. I soon realised that the scramjets became very hot at high Mach numbers and I needed to take a suitable course on this topic. A few weeks later the next McGill lecture programme was published naming me as lecturer on Advanced Heat Transfer! When I pointed out this error to the Professor of Heat Transfer he told me “but you said you wanted to take the course”, and when I pointed out that I did not know much advanced heat transfer, his response was “you very quickly will”, and he was right! As a result of this experience, plus having a team of research students and good grant money from the Canadian government I was then appointed as Professor of Mechanical Engineering.
On returning to the UK, I was offered a job at the University of Sheffield’s Department of Fuel Technology to solve the global problem of rockets blowing-up soon after launch. This phenomenon was solved here successfully, well ahead of American research teams, by the use of anti-swirl baffles. These can be seen even now on the current space shuttle main engines. Professor Meredith Thring was Head of the Department at Sheffield, and plans to test rockets containing 20lbs of cordite in the room under his desk were quickly abandoned after marks on the room ceiling were noted, and a more suitable test site at Harpur Hill, Buxton (now the Health and Safety Laboratory) was obtained from the Air Ministry.
At that time, there were several combustion research groups investigating coal and oil fuel systems experimentally at Sheffield, Leeds, etc., with rigs capable of a few kilowatts, whilst some larger scale work was carried out at the National Gas Turbine Establishment (NGTE), Leatherhead, and in industrial facilities. The combustion system design methods were typically based on: entrainment coefficients, stirred reactor networks and furnace zone models.
As you all know, it was in this empirical environment that Professor ‘Med’ Thring set up the International Flame Research Foundation to carry out furnace combustion research at industrial Megawatt scale with state-of-the-art instrumentation and science-based data analysis. Most of the IFRF experimental furnaces were used to investigate coal combustion since this was the fuel used most widely by the steel, cement and power industries, due to its lower cost compared to oil and gas. Meanwhile, the underpinning physics and chemistry knowledge was developed using research projects such as single particle or droplet combustion, and the governing equations were enumerated by people such as Professor Spalding at Imperial College.
The IFRF technical programme was coordinated by a steering group of industrial and academic members, and excellent communication of results was achieved by regular meetings and publications. The task of Chairman and project guidance was carried out by the IFRF Superintendent of Research, Med Thring, who also held the position of Head of Department at the University of Sheffield. After a few years, and due to his wife being somewhat disabled, Med became interested in the technology of a ‘mechanical housemaid’ robot which would carry out tasks such as dusting the mantelpiece without knocking the clock off. Unfortunately it was not always successful and cheaper devices on the mantelpiece were certainly recommended! One ingenious device was developed that was intended to extinguish fires in warehouses by wandering around the building then shooting a water jet at any fire discovered by an electronic eye. This device was exhibited to a leading member of Royalty in the Department yard by using burning rags on a long pole carried by a ‘willing’ technician. Whilst success had been demonstrated in the laboratory, when used outside, it insisted on shooting water at the sun which was brighter than the burning rag. Unfortunately, the robot was unsuccessful at extinguishing the sun. Nevertheless, it was strongly recommended that you avoided standing with your back to the sun!
After a significant number of years, Professor Thring left Sheffield to take up a Mechanical Engineering Chair at Queen Mary College in London, where I understand that he investigated automatic control systems. Professor János (John) Beér was then appointed as Department Head at Sheffield, and he also took over the role of IFRF Superintendent of Research in 1970. John Beér is an outstanding world authority on coal-fired power stations, including the boilers and research into their combustion systems. Under his guidance, the IFRF did outstanding work on phenomena such as swirl burner characteristics and details of two-phase turbulent flame combustion dynamics.
After John Beér moved to MIT in the USA in 1989 and I became Sheffield Head of Department, I was asked to take on the role of IFRF Superintendent of Research. Based on my idea that each Superintendent could contribute their particular field of expertise to the overall programme, I recommended that the Superintendent of Research should spend three years as Deputy Superintendent, when they would help to specify the future programme. During the subsequent three years, they would help to see the implementation of their planned programme.
With the intention that I would encourage the use of CFD to assist the analysis, interpretation and use of the vast amount of IFRF experimental data, I accepted the task. My wish for a successor to follow me was to appoint an expert in the chemistry of environmental pollutants since this was a hot topic at that time. The chosen Superintendent was Gerard de Soete (of IFP in France), who was a leading expert on emissions and their complex chemical mechanisms.
In order to help IFRF utilise the Fluent features of CFD technology that Dr Boyson and I had developed at Sheffield, it was arranged that Roman Webber (who worked in our Team) would move to IFRF in 1985, where he was a tower of strength for many years. In my view this modelling approach nicely balanced the IFRF’s experimental programme, and subsequently gave industry the means to apply IFRF combustion information more readily in their specific situations.
Nevertheless, and finally, one of my strongest recollections of IJmuiden days at the IFRF is of the wonderful evenings, sailing on the canal and enjoying jazz played by the IFRF’s incredibly talented ‘Blue Flame Band’. In my quiet moments I still dream of those days…”
Throughout Jim’s recollections, you could have heard a pin drop in the cavernous former steel mill where the dinner was being held. Such is the respect in which this world-renowned combustion engineer is held.
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