For Fuel 1 (BDN) at 550, 1,100 and 1,650 Bar Injection Pressures
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City Research Online City, University of London Institutional Repository Citation: Fatmi, Zeeshan (2018). Optical and chemical characterisation of the effects of high-pressure hydrodynamic cavitation on diesel fuel. (Unpublished Doctoral thesis, City, University of London) This is the accepted version of the paper. This version of the publication may differ from the final published version. Permanent repository link: https://openaccess.city.ac.uk/id/eprint/22683/ Link to published version: Copyright: City Research Online aims to make research outputs of City, University of London available to a wider audience. Copyright and Moral Rights remain with the author(s) and/or copyright holders. URLs from City Research Online may be freely distributed and linked to. Reuse: Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. 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City Research Online: http://openaccess.city.ac.uk/ [email protected] OPTICAL AND CHEMICAL CHARACTERISATION OF THE EFFECTS OF HIGH-PRESSURE HYDRODYNAMIC CAVITATION ON DIESEL FUEL Zeeshan Fatmi This thesis is submitted in fulfilment of the requirements of the degree of Doctor of Philosophy School of Mathematics, Computer Science and Engineering Department of Mechanical Engineering February 2018 i Table of Contents 2.1 Diesel Fuel................................................................................................................... 7 2.1.1 Distillation from Crude Oil and Conversion Processes ....................................... 7 2.1.2 Diesel Fuel Components .................................................................................... 10 2.1.3 Diesel Fuel Properties and Performance Parameters ......................................... 14 2.1.4 Additives ............................................................................................................ 20 2.1.5 Alternative Fuels ................................................................................................ 21 2.2 Modern Diesel FIE .................................................................................................... 25 2.2.1 Spill Valves and In-Vehicle Fuel Recirculation ................................................ 26 2.3 Deposits in Diesel FIE............................................................................................... 30 2.3.1 Internal Injector Deposits ................................................................................... 31 2.4 Cavitation .................................................................................................................. 34 2.4.1 Cavitation Bubble Dynamics ............................................................................. 37 2.4.2 Acoustic Cavitation ............................................................................................ 46 2.4.3 Hydrodynamic Cavitation .................................................................................. 55 2.5 Effects of Cavitation on Diesel ................................................................................. 63 2.5.1 Cavitation Induced Pyrolysis ............................................................................. 63 2.5.2 Hydrodynamic Cavitation and Pyrolytic Effects ............................................... 67 3.1 High Pressure Cavitation Test Rig ............................................................................ 75 ii 3.1.1 Temperature Control System ............................................................................. 77 3.1.2 Nozzle Description............................................................................................. 78 3.1.3 Pressurised Receiving Cylinder ......................................................................... 80 3.2 In-situ Laser Transmission Setup .............................................................................. 82 3.3 Ultraviolet-Visible Spectroscopy .............................................................................. 84 3.4 Laser Particle Count .................................................................................................. 86 4.1 Fuel Filling, Flushing and Draining Procedures ....................................................... 90 4.2 In-situ Laser Transmission Setup Calibration ........................................................... 91 4.2.1 Spectral Attenuation Data Analysis ................................................................... 93 4.3 UV-Visible Spectra Measurement Sample Dilution Methodology........................... 94 4.3.1 Dilution Repeatability and Statistics .................................................................. 97 4.4 Author’s Note .......................................................................................................... 100 4.5 Laser Particle Count Dilution Methodology ........................................................... 102 4.6 Two Dimensional – Gas Chromatography (GC x GC) ........................................... 103 4.6.1 GC x GC Sample Preparation and Analysis .................................................... 107 5.1 High Pressure Cavitation Experiments and the Spectral Attenuation Coefficient Measurements .................................................................................................................... 109 5.2 Fuel Dependence Tests............................................................................................ 112 5.3 Particle Count Distributions .................................................................................... 150 5.4 Combined Discussion of Fuel Tests ........................................................................ 154 iii 6.1 Combined Discussion of Pressure Dependence Tests ............................................ 176 8.1 Combined Discussion for Receiver Pressure Tests ................................................. 209 9.1 Paraffins .................................................................................................................. 215 9.2 Mono-Aromatics ..................................................................................................... 217 9.3 Di- and Tri (+)-Aromatics ....................................................................................... 219 9.4 FAME ...................................................................................................................... 221 9.5 Overall Change in Chemical Composition from GC x GC Results ........................ 221 10.1 Fundamental Observations of Hydrodynamic Cavitation ................................... 225 10.2 Chemical Behaviour of Diesel Fuels Subjected to Cavitation ............................ 227 10.3 Observation of Deposit Formation ...................................................................... 230 11.1 Kinetic Model and Setup ..................................................................................... 236 11.2 Modelling Results ................................................................................................ 244 11.2.1 CASE I: Model Surrogate Diesel Fuel without Dissolved Oxygen ................. 245 11.2.2 CASE II: Model Surrogate Diesel Fuel with Dissolved Oxygen .................... 256 11.3 Overall Discussion of Kinetic Modelling and Comparison with Cavitation Experiments ....................................................................................................................... 265 iv 12.1 Observations for the Fundamentals of Cavitation ............................................... 271 12.2 Observations for the Chemical Behaviour of Diesel Fuels ................................. 273 12.3 Recommendations for Future Work .................................................................... 275 A.1 Spectra Measurements in the 190 nm – 405 nm range ................................................. B.1 Fuel 1 (BDN) Experiments ........................................................................................... C.1 Pre-cavitation Sample Chromatograms ......................................................................... D.1 Model Fuel without dissolved Oxygen gas (Case I) ..................................................... E.1 High-pressure Test-rig Draining, Refilling and Flushing Procedures........................... E.2 Sample dilution method for UV-Visible Spectra measurements .................................. E.3 Sample dilution method for Laser Particle Count ......................................................... v List of Figures Figure 2.1 Paraffins with the chemical formula C8H18: a) normal octane b) isooctane or 2,4- dimethylhexane ........................................................................................................................ 11 Figure 2.2 Naphthenes with a single and double ring formation a) ethylcyclohexane b) decalin (bicyclodecane) ........................................................................................................................ 12 Figure 2.3 A hexene molecule with a double bond between third and fourth carbon atoms. .. 13 Figure 2.4 A benzene molecule with six carbon atoms. The dotted line represents the aromatic bond.......................................................................................................................................... 14 Figure 2.5 Typical distillation curve