Final Activity Report Summary - ECHTRA (Excellence in combustion and heat technology research and application)
The project ECHTRA was devoted to fundamental study of the lean-burn combustion systems. Application of these systems in engines and in industry makes possible to work with high thermal efficiency and low emission of toxic components of the combustion gases. Studies were carried out in a form of experiments and numerical simulations.
All scientific problems were studied in three groups of subjects:
1. Study of flame propagation and extinction in a swirling mixture. In many experiments and numerical simulations the most characteristic features of such flame were investigated. The mechanism of flame propagation and extinction in a field of high centrifugal forces was extensively discussed and presented at different international scientific meetings. The results were published in high level scientific journals and as a chapter of a book.
2. Study of limit flames propagating in flammability limit tubes, closed vessels and in quenching channels.
2.1. The most extensive activity was carried out in a study of the mechanism of flame propagation and extinction in flammability limit tubes. Experiments were performed in tubes of different diameters. The details of different phenomena observed in experiments were analysed with help of numerical simulations. It was found that the mechanism of flame extinction depended on mixture properties (Lewis number) and on tube diameter. The identified mechanisms of flame extinction were discussed in detail and summary of these discussions published in journals related to Combustion Institute. The results of this study were also included to one of the chapters of a book.
2.2. Constant volume combustion of lean-limit methane / air and lean-limit propane / air mixtures were extensively studied under gravity and microgravity conditions. The laminar burning velocity of limit flames, stretched and un-stretched, was determined. This velocity is one of the key parameters, which plays significant role in evaluating and calibrating chemical reaction mechanisms. The results were presented on several international scientific conferences and papers were sent for publication.
2.3. Extensive experimental study of flame propagation and extinction in quenching channels were carried out with the use of visualisation methods. Many fundamental parameters characterising flame under quenching conditions were determined as a function of equivalence ratio: quenching distance, radius of flame curvature, dead space and limit propagation velocity. The experiments were followed with numerical simulations. The results of simulations were compared with experimentally determined parameters. The thermal structure of near limit flames was determined and analysed. The results of experiments and numerical simulations were presented on many international scientific conferences and published in many journals. Summary of this study was published as a chapter of a book.
3. Experiments carried out in a rapid compression machine were devoted to detailed study of the combustion process in a swirling mixture, at high compression ratio, under engine like conditions. The results were presented at different international scientific meetings and published in internationally recognised journals. More detailed description can be found in periodical reports.
All scientific problems were studied in three groups of subjects:
1. Study of flame propagation and extinction in a swirling mixture. In many experiments and numerical simulations the most characteristic features of such flame were investigated. The mechanism of flame propagation and extinction in a field of high centrifugal forces was extensively discussed and presented at different international scientific meetings. The results were published in high level scientific journals and as a chapter of a book.
2. Study of limit flames propagating in flammability limit tubes, closed vessels and in quenching channels.
2.1. The most extensive activity was carried out in a study of the mechanism of flame propagation and extinction in flammability limit tubes. Experiments were performed in tubes of different diameters. The details of different phenomena observed in experiments were analysed with help of numerical simulations. It was found that the mechanism of flame extinction depended on mixture properties (Lewis number) and on tube diameter. The identified mechanisms of flame extinction were discussed in detail and summary of these discussions published in journals related to Combustion Institute. The results of this study were also included to one of the chapters of a book.
2.2. Constant volume combustion of lean-limit methane / air and lean-limit propane / air mixtures were extensively studied under gravity and microgravity conditions. The laminar burning velocity of limit flames, stretched and un-stretched, was determined. This velocity is one of the key parameters, which plays significant role in evaluating and calibrating chemical reaction mechanisms. The results were presented on several international scientific conferences and papers were sent for publication.
2.3. Extensive experimental study of flame propagation and extinction in quenching channels were carried out with the use of visualisation methods. Many fundamental parameters characterising flame under quenching conditions were determined as a function of equivalence ratio: quenching distance, radius of flame curvature, dead space and limit propagation velocity. The experiments were followed with numerical simulations. The results of simulations were compared with experimentally determined parameters. The thermal structure of near limit flames was determined and analysed. The results of experiments and numerical simulations were presented on many international scientific conferences and published in many journals. Summary of this study was published as a chapter of a book.
3. Experiments carried out in a rapid compression machine were devoted to detailed study of the combustion process in a swirling mixture, at high compression ratio, under engine like conditions. The results were presented at different international scientific meetings and published in internationally recognised journals. More detailed description can be found in periodical reports.