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U.S. Naval Academy 410-293-6339 / [email protected] Current and Future Navy Challenges with Hydrocarbon Fuels

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U.S. Naval Academy 410-293-6339 / Prak@Usna.Edu Current and Future Navy Challenges with Hydrocarbon Fuels U.S. Naval Academy 410-293-6339 / [email protected] Current and Future Navy Challenges with Hydrocarbon Fuels Petroleum-based fuels sources around the world vary in properties • Need to constantly monitor fuel quality • Europe mixes biodiesel with diesel Conventional petroleum prices are currently low (< $50 / barrel) • Favorable situation for petroleum-based fuels • Alternative fuels: currently more expensive ‒ Environmental movement maintains interest ‒ Future costs may increase economic viability ‒ The composition of these fuels can be dramatically different than conventional fuels. These differences can lead to performance issues. NEEDED: Ability to predict properties and performance given knowledge of fuel composition Image from https://en.wikipedia.org/wiki/World_map#/media/File:Winkel_triple_projection_SW.jpg http://www.cnbc.com/2015/10/25/oil-prices-drop-demand-seen-sagging-towards-year-end.html 2 Fuel Hydrocarbon Distribution HRD-algae olefins HRJ-camelina CHC cyclo- Jet/Diesel DSH-sugars/biomass oils alkanes iso-alkanes HDCD-wood ATJ-sugars/biomass aromatics Reactivity (cetane) Number of Carbon Atoms 3 Goals of Neptune Funding Measurement of Chemical and Thermophysical Properties of Fuels and Organic Liquid Mixtures • Chemical composition, density, viscosity, surface tension, flash point, heat of combustion, distillation curve Prediction of Thermophysical Properties through Atomistic Modeling • Develop a computer model for calculating thermophysical properties of fuels based on their chemical composition Characterization of Diesel Engine Combustion • Evaluate Fuels and fuel blends of interest to the Navy • Study the effects of changing physical and chemical properties Support the Navy Mission • Educate future Navy leaders in the Science and Engineering of Fuels • Support Navy and NAVAIR to help them respond to emerging Navy fuel needs NAVY IMPACT: Facilitate the “fit for purpose” determination of Navy fuels. Educate future Navy leaders. Support the Navy response to emerging fuel needs. 4 Synergy of the USNA Research Efforts Jim Cowart Combustion Physical/Chemical Properties Len Hamilton Modeling Fuel Determination Development of Properties & of the impact model of properties composition on combustion Refinement Combustion behavior Pure & multi- & validation of fuels & component of mixtures data predictive models Preparation and measurement of properties of mixtures Dianne Luning Prak with known composition Dan O’Sullivan Judith Harrison Paul Trulove Mixture Development Fuels & some fuel Navy Air Systems Andy McDaniel properties Command Terrence Dickerson 5 Physical and Chemical Analysis of Fuels Gas Chromatograph / Analytical Methods Mass Spec (GC/MS) • Gas Chromatograph / 200 100 Mass Spec (GC/MS) for Fuel JP-5 fuel characterization Properties & • Density composition • Viscosity 100 0 • Speed of Sound ATJ-8 Dianne Luning Prak Relative Intensity • Surface Tension Dan O’Sullivan Paul Trulove 0 -100 • Heat of combustion 25811 • Bulk modulus Time (min) Major components Alcohol-to-Jet fuel (ATJ-8) • 2,2,4,4,6,8,8- heptamethylnonane • 2,2,4,6,6-pentamethylheptane Fuel spray We= ρ v2 l / σ 6 Development of Surrogate Mixtures Fuel Properties & composition Preparation and measurement of properties of mixtures with known composition Fuel Surrogate** Mixture Development **Fuel Surrogates are mixtures of one or more simple fuels that are designed to emulate the physical properties/combustion properties of a more complex fuel. 7 Development of Surrogate Mixtures for Alcohol-to-Jet fuel (ATJ-8) Determination of optimal mixture composition for ATJ-8 surrogate using measured properties Similar 790 behavior for 780 other properties -3 770 /kg∙m 760 density 750 ATJ fuel density 740 0 0.2 0.4 0.6 0.8 1 mole fraction of 2,2,4,4,6,8,8-heptamethylnonane in 2,2,4,6,6- pentamethylheptane 0.23 mole fraction of 2,2,4,4,6,8,8-heptamethylnonane in 2,2,4,6,6- pentamethylheptane mixture tested in combustion experiments 8 Combustion of Fuels and Surrogates using Various Military Engines Jim Cowart Combustion Len Hamilton Fuel Determination of the impact Properties & of properties composition on combustion Combustion behavior of fuels & mixtures Preparation and measurement of properties of mixtures with known composition Mixture Development Fuels & some fuel Navy Air Systems Andy McDaniel properties Command Terrence Dickerson 9 Combustion of Fuels and Mixtures using Various Instrumented Engines Jim Cowart Len Hamilton Humvee Diesel Yanmar Small Diesel Generator Waukesha Cetane Cummins Diesel Test Engine (small boat propulsion) 10 New Fuel Combustion Acceptance Criteria Impact on Torque & Power Top Dead Center (TC) ±5 % ± 10% Ignition Delay Ratio Injection Peak Pressure Location Chamber Pressure Rate of Heat Release Ratio Acceptance criteria built upon Time comparison to key combustion properties of existing (base) fuel Cowart, J.S., Hamilton, L.J., Williams, S.A. and McDaniel, A., ‘Alternative Diesel Fuel Combustion Acceptance Criteria for New Fuels in Legacy Diesel Engines’, Society of Automotive Engineers’ International Congress, Detroit, MI, April 2013. 11 Combustion of Fuels & Mixtures: Analysis of Engine RPM & Centane Number 4000 Derived Cetane Number 3500 JP-5 45 3000 80% JP-5/20% ATJ 42 2500 70% JP-5 2000 70% JP-5, 30% ATJ 70% JP-5, 30% optimal surr. ATJ 40.4 RPM (rev/min) RPM 1500 70% JP-5, 30% isododecane Optimal surrog. 40.2 70% JP-5, 30% isocetane JP-5 Isododecane 40.6 1000 60% JP-5, 40% ATJ Isocetane 39.1 80% JP-5, 20% ATJ 500 0 10 20 30 60% JP-5/40% ATJ 38 time since start (sec) • Navy target: 10 s for emergency diesel generators Yanmar L100V single-cylinder diesel engine 12 Combustion of Fuels & Mixtures: Analysis of Engine RPM & Centane Number 4000 Derived Cetane Number 3500 3000 80% JP-5/20% ATJ 42 2500 70% JP-5 2000 70% JP-5, 30% ATJ 70% JP-5, 30% optimal surr. ATJ 40.4 RPM (rev/min) RPM 1500 70% JP-5, 30% isododecane Optimal surrog. 40.2 70% JP-5, 30% isocetane JP-5 Isododecane 40.6 1000 60% JP-5, 40% ATJ Isocetane 39.1 80% JP-5, 20% ATJ 500 0 10 20 30 60% JP-5/40% ATJ 38 time since start (sec) • JP-5: ramps up to rated speed the fastest 13 Combustion of Fuels & Mixtures: Analysis of Engine RPM & Centane Number 4000 Derived Cetane Number 3500 JP-5 45 3000 2500 70% JP-5 2000 70% JP-5, 30% ATJ 70% JP-5, 30% optimal surr. ATJ 40.4 RPM (rev/min) RPM 1500 70% JP-5, 30% isododecane Optimal surrog. 40.2 70% JP-5, 30% isocetane JP-5 Isododecane 40.6 1000 60% JP-5, 40% ATJ Isocetane 39.1 80% JP-5, 20% ATJ 500 0 10 20 30 time since start (sec) > 30 seconds • JP-5: ramps up to rated speed the fastest • Increasing ATJ: Time to reach the rated speed increases – combustion fails above 60% JP-5/ 40% ATJ 14 Combustion of Fuels & Mixtures: Analysis of Engine RPM & Centane Number 4000 Derived Cetane Number 3500 JP-5 45 3000 80% JP-5/20% ATJ 42 2500 70% JP-5 2000 70% JP-5, 30% ATJ 70% JP-5, 30% optimal surr. ATJ 40.4 RPM (rev/min) RPM 1500 70% JP-5, 30% isododecane 70% JP-5, 30% isocetane JP-5 1000 60% JP-5, 40% ATJ 80% JP-5, 20% ATJ 500 0 10 20 30 60% JP-5/40% ATJ 38 time since start (sec) • JP-5: ramps up to rated speed the fastest • Increasing ATJ: Time to reach the rated speed increases – combustion fails • All surrogates similar to ATJ: optimal surrogate 0.23 isocetane in isododecane 15 Combustion of Fuels and Mixtures: Change in Ignition Delay with Time Large Yanmar Derived Cetane Number 100 80 60-40ATJ 45 60 80% JP-5/20% ATJ 42 40 70% JP-5/30% ATJ 40 IGD-ten (deg) 20 60% JP-5/40% ATJ 38 0 0 5 10 15 20 25 30 time since start (sec) • JP-5: has the smallest ignition delay • ATJ: Ignition delay increases and combustion is uneven as ATJ is added and is accompanied by an increase in cetane number 16 Synergy of the Research Efforts Physical/Chemical Properties Modeling Fuel Development of Properties & model composition Refinement Pure & multi- & validation component of data predictive models Preparation and measurement of properties of mixtures with known composition Judith Harrison 17 Molecular Dynamics Simulations: Predicting Fuel Properties Pre-Processing: Simulation Setup z (User Supplied Input or GC/MS measurement ) e.g.) Positions, velocities, charges, topology of all atoms, y temperature , flags for simulation parameters x Calculate Interatomic Forces (Potential Function Selection) F = - dV(r)/dr V = AIREBO1 OPLS-AA3 Bulk Properties: 2 or mod-LJ AIREBO Non-Reactive Force Fields, updated recently Hydrocarbon liquid Reactive Potentials, Input = Positions only Input = Positions, Topology, charges, etc. Fuel Properties of Interest (all as a function of temp) Mathematically Integrate Equations of Motion • Density -Predictor-Corrector, Berendsen Thermostat, Nose-Hoover • Bulk modulus - NVT, NVE or NPT dynamics • Heats of vaporization ----Future work----- Output or Calculation of Values for FFP Calculation • Viscosity • Surface Tension Creation of Algorithms: (1) scripts for creating fuel simulation • Heat of combustion systems, (2) calculation of run-time quantities, (3) creation of • Specific Heat data files and algorithms for post-processing analysis • Interfacial Tension 1J. Chem Phys. 112, 6472 (2000); 2J. Comp. Chem., 29, 601-611 (2008); 3J. Am. Chem. Soc. 118 , 11225 (1996) 18 Selecting Systems for Fuel Property Prediction Strategy: Examine the performance of the mod-LJ AIREBO and OPLS-AA potentials predicting properties as a function of temperature of complex, pure hydrocarbons and surrogate mixtures. USNA collaborators are able to provide any needed experimental data. For example: J. Chem. Eng. Data, (2014) 59, 1334. AJT data/surrogates:
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