In this study of combustion under forced convection, the physical process of cigarette smoking has been investigated. The mechanism during the smoking cycle has been studied under a large variety of conditions by varying puff volumes, cigarette sizes and other parameters 0 A simple unidimensional theory of smoulder under forced convection has been derived and tested by experiments with an adiabatic graphite-particle bed. The theory is shown to be correct for the graphite bed but too elementary to represent cigarette combustion, except in differential form. A working hypothesis is suggested for the smoking process, which has been substantiated by experiments including the measurement of consumption patterns and the recording of the external distribution of hot gases by schlieren photography. Temperature distributions and absolute temperature maxima in cigarettes have been determined by two new methods one of which is dependent upon a new device - a high intensity, low energy, x-ray source.. This device was used for the recording of isothermals in opaque materials by the cine-x-radiography of the melting of finely divided inert metal inclusions. The second method is an extension of optical radiation pyrometry applied to the recording of rapid temperature fluctuations. A study of consumption patterns was made by quenching cigarettes in liquid nitrogen at different stages in the smoking process. Measurements on the resulting stubbs enabled amounts of tobacco consumed to be correlated with the parameters of smoking. An elementary diffusion-controlled theory for natural smoulder is developed and compared with practice. Experiments on the heat of co mbustion of tobacco and tobacco/air stoichiometry provide values enabling a theoretical natural smoulder combustion zone temperature to be predicted. This research has resulted in the elucidation of all the principal features of the physical mechanism of smouldering in cigarettes and in the development of new research methods.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602206 |
| Date | January 1963 |
| Creators | Gugan, Keith |
| Contributors | Weinberg, F.J. ; Egerton, Alfred C. |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/13276 |
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