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|Title:||The influence of jet precession on particle distributions.|
|Author:||Birzer, Cristian Heinrich|
|School/Discipline:||School of Mechanical Engineering|
|Abstract:||This thesis assesses the extent to which jet precession can be used to control the mean and instantaneous particle distributions in particle-laden jet flows. Investigations were conducted, providing quantitative, planar measurements of instantaneous particle distributions in the first 10 nozzle diameters of a particle-laden co-annular nozzle with centrally located Precessing Jet (PJ). Equipment was specifically designed to conduct the investigations, a laser diagnostic technique developed and a methodology to quantify particle clusters was devised. The experimental facilities are scaled to simulate the near burner region of a typical rotary cement kiln. The laser diagnostic technique, called planar nephelometry, enables non-intrusive, quantitative, instantaneous, planar measurements of particle distributions without the need to identify individual particles. The methodology to quantify particle clusters is designed to enable statistical comparison of clusters without ambiguity. Measurements of the influence of particle mass loading and jet precession on the distribution of particles emerging from an particle-laden co-annular nozzle, with a centrally located PJ nozzle, are presented. These data include mean and standard deviation of the particle distributions and statistics on particle cluster characteristics. The results indicate that small amounts of momentum through the PJ nozzle causes an elongation of the jet, but larger amounts of momentum through the PJ nozzle will result in a wider mean particle distribution and greater mean centreline decay rate. An increase in jet precession also results in an increase in the fluctuations in the particle distributions. The transition is determined by the interplay of momentum of the particle-laden and precessing streams. The physical characteristics of identified particle clusters in the instantaneous planar flow field are also influenced by jet precession. An initial increase in the amount of jet precession results in an overall decrease in the average number of both small- and large-clusters. The size of small-clusters generally reduces with increasing jet precession, whereas large-clusters reach maximum sizes for an intermediate relative momentum of jet precession. Analogous to the influence of jet precession on the mean distribution of particles, increasing jet precession also results in a greater spread of small- and large-clusters. Results also indicate that increasing the mass flow rate of particles results in an elongation of the jet. However, these variations correspond to an increase in annular jet momentum, rather than an addition of secondary phase. The particle mass flow rate has a minor influence on the general characteristics of particle clusters.|
Kalt, Peter Anthony Markus
Smith, N. L.
|Dissertation Note:||Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2009|
|Keywords:||jet precession; two-phase flows; laser diagnostics; particle clusters|
|Provenance:||Copyright material removed from digital thesis. See print copy in University of Adelaide Library for full text.|
|Appears in Collections:||Research Theses|
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