Spark ignition (SI) and compression ignition (CI) engine fuels are characterized by standards developed in 1927 and 1932, respectively. Over the course of these years, modern engines have drastically changed their operating conditions; however, these fuel indexes are still used today with no significant change to their definition. The requirements for fuels in future advanced engines, employing low temperature combustion (LTC) concepts, may be somewhere between gasoline and diesel in terms of their autoignition characteristics. With this focus, this study examines methodologies to bridge the gap between those fuels classified between gasoline and diesel. First, the ignition delay times (IDTs) at various temperatures obtained from an ignition quality tester (IQT), was correlated with the octane index (OI), an anti-knock scale combining the effect of the operating condition and the anti-knock quality of the fuel given by the RON/MON. This study was extended to introduce a new concept of IDT sensitivity (IDS) in an IQT. It was observed that IDS could be correlated with fuel octane sensitivity (OS = RON − MON), offering an additional methodology to estimate RON/MON with an IQT. Chemical kinetics are most sensitive to fuel molecular structure; remarkable progress has been made in covering high carbon-number fuels, relevant to gasoline fuels, for better understanding of the chemical processes that lead to engine knock. To this end, a methodology to relate IDTs calculated from homogeneous batch-reactor simulations with gasoline fuel indexes was developed. This methodology enabled correlation of a kinetic property (i.e., IDT) with RON/MON values. The influence of various components present in gasolines, and their anti-knock quality, was investigated. A spinning band distillation system was utilized to separate the components of various gasolines. Ignition quality and the functional group distribution of various boiling ranges were investigated with an IQT and 1H nuclear magnetic resonance (NMR) spectroscopy. Finally, the importance of physical and chemical fuel properties in fuel stratification in LTC engine concepts was undertaken in a CI engine with a multi hole solid-cone injector. The findings suggest that the physical properties of fuel played a dominant role when fuel stratification occurred in the engine combustion chamber.

Variable valve actuation remains one of the most studied technologies for diesel engines for fuel benefits, efficiency improvements and emission control. The same can be implemented on natural gas engines however presence of throttle valve in the spark ignited natural gas engine leads to different set of challenges and outcomes. In this document, focus is on GT power led analyses for a mid-range natural gas engine and the VVA strategy applied is modulation of intake valve closure timing. The simulations are run for early intake valve closure and late intake valve closure, both applied independently and run for steady state conditions. The focus is on the low torque range to study the impact of IVC modulation on throttling losses for low torque region. The simulation studies showed that IVC strategies both early as well as late IVC do benefit in terms of thermal efficiency improvements by up to 3% and reduction in brake specific fuel efficiency by up to 13%.It also showed considerable reduction in pumping loop and increase in open cycle efficiency when IVC modulation is applied. Validating the model further with real on-engine data and then calibrating the existing GT power with the on-engine data to validate the conclusions drawn would be the next set of goals for this project.<div><br></div><div>Second part of this document is focused on real life testing of soy biodiesel fueled heavy duty on-road engine with modern exhaust aftertreatment system with SCR. Soybean based biodiesel remains one of the most sought-after alternate fuel and biofuel to be used in on-road engines. Burning biodiesel leads to a cleaner exhaust compared to conventional diesel as the biofuel is oxygenated fuel leading to more complete combustion and lower amount of emission species such as CO, CO2and PM in the exhaust. The experiments discussed in this document consisted of developing torque curve envelopes and steady state tests (RMC set points). Three soy biodiesel blends were studied which included B20-20% biodiesel, B50 –50% biodiesel and B100 –100% biodiesel. NOx emissions were observed to be considerably higher for B100 at engine outlet by up to80% as well as at tailpipe outlet increased by up to380%, compared to that of conventional diesel which is attributed to the thermal mechanism of NO production. The exhaust gas temperatures were observed to be lower by up to40-degreeC while the urea dosing was considerably higher by up to83% when using biodiesel blend B100.Thisresearch paves the way to testing further using varying biodiesel blends for regulation certification trials, for tuning the diesel engines for different biodiesel blends and for developing the control strategy for the existing diesel engines to accommodate biodiesel.<br><div><br></div></div>

This thesis concerns with design of manufacturing system for specific company. Object of manufacture is warmwater boiler for solid fuels. Analysis of this object, design of necessary technologies, manipulation and transportation concept, layout concept and economic efectiveness of investment realization evaluation are apart of this thesis.

Although the suspended droplet evaporation and combustion have been studied for decades, fundamental research pertaining to the stochastic phenomena of complex multicomponent mixtures is extremely rare. In this work, an experimental suspended droplet study of Arabian light oil was held to study the frequency of puffing and micro-explosion phenomena during the evaporation/pyrolysis process. The experiments were conducted at three different evaporation temperatures (350 C, 440 C, and 570 C), chosen in accordance with the TGA profle obtained. The suspended droplet experiments were conducted on a furnace with optical access and a gas controlled-preheating system. The droplet size was optically registered at 500 fps by a LaVision Imager Pro HS high-speed camera coupled with a magnification lens Nikon AF-S Micro Nikkor 105 mm. Furthermore, a computer-vision data postprocessing program was developed to identify contours and measure the size of the objects in the frame in order to register the temporal evolution of the droplet size. Additionally, a new approach for characterizing the droplet vaporization of complex multi-component fuels is proposed. This method allowed us to study the continuum (ideal evaporation) and stochastic processes separately, by following the profile of the average normalized square diameter ((D=D0)2) and quantifying the breakup intensity (β) of each stochastic event. Based on the behavior of (D=D0)2, two consecutive stages were identified at every temperature investigated, the swelling and the regression stage. At 350 ◦C and 440 ◦C, the evaporation was finally controlled purely by the diffusion evaporation, whereas at 570 ◦C a pure diffusion stage was not spotted. Instead, a second swelling was registered, where an amorphous carbonaceous structure was formed. Due to the pyrolysis of the heavy hydrocarbons dominated the process. The stochastic events involved during the evaporation were successfully identified and classified in breakup modes depending on their β. Additionally, the effect of the temperature on the breakup events was assessed. Showing that the number of breakup events increased exponentially with temperature.

>Magister Scientiae - MSc / The global dependence on non-renewable fossil fuels to meet energy needs cannot be sustained for a long time and it is already evident in the escalation of fuel prices over the past decade. This research was performed towards renewable energy production from agricultural and food waste. The use of agricultural and food waste has benefits such as being grown in a land that is not in competition with food crops protein, all year round availability, and having high lipid content. The produced bio-crude oil can be upgraded to remove moisture and acidity level, and can be used as a substitute for heavy oils such as diesel to power static appliances or can be used as petrol distillate fuel alternative. Hydrothermal liquefaction (HTL) process is one of the commonly used technologies for converting agricultural and food waste into liquid biofuels.

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Atomization can be achieved by discharging liquid at relative high velocities into a slow moving environment (hydraulic nozzles) or by discharging liquid at low velocities into a fast moving gas flow (air-blast nozzles). These two types of injector nozzles are featured in majority of the industry applications such as power generation, food or pharmaceutical powder formation, spray painting, petroleum refining, and thermal sprays. The most common atomizer used in combustion engines is the pressure-swirl nozzle (Simplex nozzle) to obtain a homogenous mixture at different equivalence ratios. The experimental studies performed with pressure-swirl nozzles have reported contradictory results over the last few years. Thus, the fundamentals of spray dynamics, such as spray formation, liquid breakup length, droplet breakup regimes, and coalescence still need to be understood for a pressure-swirl nozzle. An experimental study of the breakup characteristics of various liquids and fuels with different thermal physical properties emanating from hollow cone hydraulic injector nozzles induced by pressure-swirling was investigated. The experiments were conducted using two nozzles with different orifice diameters 0.3mm and 0.5mm and injection pressures (0.3-4MPa) which correspond to Rep = 7,000-31,000 depending on the liquids being tested. Three laserbased techniques, i.e., Shadowgraph, Particle Image Velocimetry (PIV) and Phase Doppler Particle Anemometry (PDPA) were utilized in this study. Although each technique had its limitation in different flow regimes, the results were cross-validated, and generally showed correct trends in axial and radial measurements of velocity and diameter for different nozzles, Weber and Reynolds numbers. iii The spatial variation of diameter and velocity arises principally due to primary breakup of liquid films and subsequent secondary breakup of large droplets due to aerodynamic shear. Downstream of the nozzle, coalescence of droplets due to collision is also found to be significant. Different types of liquid film break up was considered and found to match well with the theory. The spray is subdivided into three zones: near the nozzle, a zone consisting of film and ligament regime, where primary breakup and some secondary breakup take place; a second zone where the secondary breakup process continues, but weakens, and the centrifugal dispersion becomes dominant, and a third zone away from the spray where coalescence is dominant. Each regime has been analyzed in detail to understand the effect of surface tension and viscosity. Surface tension and viscosity were engineered to mimic fuels, which were then compared with real fuels such as Ethanol, Jet-A and Kerosene. Results show similarity in the diameter in the beginning stages of breakup but in the coalescence regime, the values deviate from each other, indicating that the vapor pressure also plays a major role in this regime.

ABSTRACT EFFECTS OF WILDLAND-URBAN INTERFACE FUEL TREATMENTS ON POTENTIAL FIRE BEHAVIOR AND ECOSYSTEM SERVICES IN THE CENTRAL SIERRA NEVADA MOUNTAINS OF CALIFORNIA Christopher C. Hamma For the past several decades, the wildland-urban interface (WUI) has been expanding in the low- to mid-elevation mixed-conifer belt of California’s Sierra Nevada mountain range. Concurrently, the effects of fire exclusion and shifting climatic patterns in this region have led to increases in wildfire size and severity, posing an ever-greater risk to life and property. As a result, the need for implementation of fuel treatments to reduce fire hazard is generally recognized to be urgent. However, by removing vegetation, these treatments may also diminish the ability of forest ecosystems to provide valuable ecosystem services to society. Forest managers, landowners, and other WUI stakeholders would therefore benefit from a better understanding of the effects of various fuel treatment types on both fire hazard reduction and ecosystem benefits. The present study examined the effects of four commonly-used fuel treatment types on stand-level forest structural characteristics, surface and canopy fuel loading, potential fire behavior, air pollution removal, and carbon sequestration and storage. Fuel treatments involving thinning and/or prescribed burning were largely successful at reducing live and dead fuel loading, with corresponding reductions in predicted fire behavior. The little-studied but increasingly popular practice of mastication (chipping or shredding small trees and brush and leaving the debris on the ground) was associated with significantly increased surface fuel loading, although deleterious effects on potential fire behavior were not found. Overall, the findings from the fire and fuels portion of the present research largely match those reported in other, similar studies in Sierra Nevada mixed-conifer forest. However, the current analysis found little in the way of significant treatment effects on stand-level air pollution removal or carbon dynamics. This study was affected by challenges including small sample size and high variability in the data; nonetheless, the results underscore the general validity of fuel treatment implementation in central Sierra Nevada WUI areas for moderating wildfire severity and effects, with the recognition that the efficacy of such treatments may be limited under extreme weather conditions.

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