An electrostatic atomiser is an energy-eﬃcient device that can be used to promote theatomisation of highly viscous ﬂuids, for example biodiesel. It imposes an electrical chargeonto the liquid that creates enough Coulombic repulsive force to lower the surface-tensionforce of the liquid and result in atomisation.In this study, the vaporisation of electrically charged fatty-acid methyl-ester (FAME)droplets are reported as a function of the initial charge density, ambient temperature, anddroplet Reynolds number. Existing data from a direct numerical simulation (DNS) of chargeinjection are also post-processed to better understand the physics of electro-convection as afunction of the average bulk-ﬂow velocity and the electrical Rayleigh number.The model predictions are assessed by comparing with experimental results, and themaximum deviation in evaporation time is reported to be 13.6% for C12:0. The eﬀectof charge increases with increasing initial charge density and decreases at high ambient temperatures, while the droplets Reynolds number shows a mixed eﬀect. The DNS dataprocessing reveals that the developed electro-convective instabilities force the liquid into aroll-like structured motion and in a high-ﬂow-rate atomiser, higher instability could maximisethe amount of charge in the middle of the domain.
Table of ContentsAcknowledgements -- Nomenclature -- Abstract -- List of Publications -- List of Figures -- List of Tables - 1 Introduction -- 2 Literature Review -- 2.1 Introduction -- 2.2 Evaporation models for a single biodiesel droplet -- 2.2.1 Biodiesel as a single-component fuel -- 2.2.2 Biodiesel and its constituent components -- 2.3 Electrostatic atomiser -- 2.4 Chapter summary -- 3 Methodology -- 3.1 Introduction -- 3.2 Model formation -- 3.2.1 Assumptions -- 3.2.2 The governing equations -- 3.2.3 Fuel Properties -- 3.3 Solution approach -- 3.4 Evaporation of charged droplet -- 3.4.1 Charge-only case -- 3.4.2 Charge and combustion case -- 3.5 Chapter summary -- 4 Results and Discussion 4.1 Introduction -- 4.2 Model validation -- 4.3 Model predictions -- 4.3.1 Eﬀect of initial charge density -- 4.3.2 Eﬀect of ambient temperature -- 4.3.3 Eﬀect of Reynolds number -- 4.4 Chapter summary -- 5 EHD ﬂow inside the atomiser -- 5.1 Introduction -- 5.2 Theoretical study -- 5.3 Governing equations -- 5.4 Charge distribution analysis -- 5.4.1 Eﬀect of electrical Rayleigh number (T) -- 5.4.2 Eﬀect of average bulk-ﬂow velocity (Uav) -- 5.5 Chapter summary -- 6 Conclusions and future work -- 6.1 Introduction -- 6.2 Main Findings -- 6.2.1 The eﬀect of charge on FAMEs' droplet vaporisation -- 6.2.2 The charge distribution between the electrodes -- 6.3 Future work --A Appendix -- References
Bibliography: pages 65-70
Awarding InstitutionMacquarie University
Degree TypeThesis MRes
DegreeMRes, Macquarie University, Faculty of Science and Engineering, Department of Engineering
Department, Centre or SchoolDepartment of Engineering
Year of Award2017
Principal SupervisorSammy Diasinos
RightsCopyright Tushar Ahmed 2017.
Copyright disclaimer: http://mq.edu.au/library/copyright
Extent1 online resource ( xx, 70 pages) illustrations, tables