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Aerodynamics and interaction of single and multiple jets in rotation

Allen, Roger Ashton (1971) Aerodynamics and interaction of single and multiple jets in rotation. PhD thesis, University of Sheffield.

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The work contained within the body of this thesis is concerned with the isothermal aerodynamic study of multiple jet systems with special reference to flame interactions. The type of jets used were jets with or without recirculation (swirl) and simple flame interactions were shown to occur for the configurations studied. The main purpose of the study was to show the nature and degree of the aerodynamic interference and to relate these to the factors which govern flame length, stability and combustion intensity. The thesis also contains a study of the turbulence and mean flow characteristics of a swirling jet of variable swirl. The instrument used to measure the mean velocity and turbulence quantities was the hot wire anemometer, and since for the case of a strongly swirling jet each component of the mean velocity and the normal and shear stresses are significant, a technique was evolved capable of separating out each of the 9 individual terms associated with the above, namely ¯u,¯( v), ¯w, ¯(u'v'), ¯(u'w'), ¯(v'w'), ¯(〖u'〗^2 ), ¯(〖v'〗^2 ), ¯(〖w'〗^2 ). The method of analysis is based upon a new velocity voltage relationship which is accurate for all types of probe and/or flow velocity range. Previous methods of analysis were restricted to low turbulence levels where typically the local turbulence intensity (¯(〖u'〗^2 ) ½ / ¯u, ), is not more than 20%. The new method is shown to be valid until the onset of flow reversal which depends upon the type of waveform that the fluctuations in velocity take. The magnitude of the measured quantities are shown to be independent of the type of waveform and assuming that the fluctuations closely resemble a triangular waveform the maximum turbulence levels measurable are 57%.

Item Type: Thesis (PhD)
Other academic unit: Chemical Engineering and Fuel Technology
Identification Number/EthosID: uk.bl.ethos.532159
Depositing User: EThOS Import Sheffield
Date Deposited: 03 Mar 2016 10:54
Last Modified: 03 Mar 2016 10:54
URI: http://etheses.whiterose.ac.uk/id/eprint/10376

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