Objective
Dust explosions continue to be a threat to a wide range of process industries. Reliable statistics are scarce not only in the NIS, but also in the German industry where there is about one significant dust explosion a week on average. In view of the great need for upgrading the technologies in NIS process industries in general, it seems reasonable to believe that dust explosions represent an even greater problem in these countries. The limited statistics available support this view. The Russian Foundation for Basic Research (S.A.Tsyganov) states that the present project is regarded as part of science priority direction N.
In EU and associated countries a major concern in the domain of dust explosion protection is that there is no really adequate method for predicting the violence with which a given dust will explode in a given process situation. The recent EU research project CREDIT showed that developing a comprehensive numerical code for predicting rates of explosion propagation and maximum explosion overpressures in realistic industrial scenarios is a feasible approach. Thus CMR in Bergen, Norway is just starting a three-year comprehensive effort (DESPRO) to explore this possibility. In this work establishing adequate -models for the combustion process is very important. The detailed mechanism of dust cloud combustion varies with the type of dust, and special models for metal dusts such as Al, Mg and their alloys, will be needed. The role played by thermal radiation in the flame propagation process must be clarified.
The main purpose of the proposed project is to provide the knowledge needed for developing adequate combustion models for metal dust clouds. The two NIS laboratories in which this research will mainly be done, are in an excellent position to be able to accomplish this demanding task by utilising high level expertise established through many years of research on the combustion of solid rocket fuels.
The project includes studies on combustion of single volatile metal particles (Al, Mg and Al/Mg alloys), considering microscopic processes in surface films and in the gas phase, as well as global processes in ignition of and flame propagation in dust clouds. Researchers from different research teams in different countries, working in different areas of combustion science (single particles, dust clouds) and using different experimental and theoretical methods, will co-operate in studying the complicated critical phenomena in metal particle combustion to establish a link between such phenomena and global laws of flame propagation in dust/gas mixtures.
The studies on combustion of single metal particles will make it possible for the first time to elucidate the mechanisms of transients and instability in combustion of volatile metals. In studies on flame propagation in dust/gas mixtures, conduction-to-radiation ratios and the role of hydrodynamic instabilities in different combustion modes and in transients will be determined. The roles played by different energy transfer mechanisms in spark and laser ignition of metal dust clouds will be revealed for the first time, and an adequate theoretical model of dust cloud ignition will be developed. The influence of metal particle combustion mechanisms on the critical ignition conditions and modes of flame propagation in dust clouds will be clarified. This knowledge is essential in formulation of combustion models for metal dust clouds, and such models will, in turn, make it possible to give more precise safe and cost effective recommendations on prevention and mitigation of metal dust explosions, than can be given today. Combustion models for metal dust clouds developed in the present project may be used as building blocks in the work towards developing a numerical code for predicting the rate of propagation of dust explosions, within the framework of a European research programme on dust explosion prevention and mitigaion in the process industries (DESPRO) conducted by CMR (Norway) in co-operation with UoB (Norway).
Improved industrial safety, through improved dust explosion protection, is the main aim of the present research, but the results may also prove to be useful for the development of new, promising rocket engines for Mars missions, using powdered metals as fuel, and also in possible new future useful applications of metal particle combustion.
Topic(s)
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5007 Bergen
Norway