Mechanical Engineering Commons^™

An Experimental And Computational Study Of Fuel Spray Interaction: Fundamentals And Engine Applications, Le Zhao

Dissertations, Master's Theses and Master's Reports

An efficient spray injection results in better vaporization and air-fuel mixing, leading to combustion stability and reduction of emissions in the internal combustion (IC) engines. The impingement of liquid fuels on chamber wall or piston surface in IC engines is a common phenomenon and fuel film formed in the spray-piston or cylinder wall impingement plays a critical role in engine performance and emissions. Therefore, the study of the spray impingement on the chamber wall or position surface is necessary.

To understand the spray-wall interaction, a single droplet impingement on a solid surface with different conditions was first examined. The droplet-wall …

Spray And Combustion Studies Of High Reactivity Gasoline In Comparison To Diesel Under Advanced Compression Ignition Engine Conditions, Meng Tang

Dissertations, Master's Theses and Master's Reports

Gasoline compression ignition (GCI) technology has demonstrated great potentials in improving fuel economy and reducing engine-out NO_x and particulate matter emissions. Development and application of the GCI technology on multi-cylinder engines require both fundamental understandings of the gasoline spray combustion characteristics and accurate numerical tools. Due to the large differences in the thermo-physical and the chemical properties between gasoline and diesel range fuels, differences in the spray combustion characteristics between gasoline and diesel is expected. Reports on the gasoline spray combustion characteristics under conditions relevant to medium to heavy-duty engines are scarce and this dissertation aims to fill in …

Investigation On The Potential Of A Co2 Capture System, Downstream Of The Aftertreatment System For A Heavy-Duty Engine Application, Murchana Pathak

Dissertations, Master's Theses and Master's Reports

The transportation sector accounts for the second largest source of CO₂ emissions after power generation. New Corporate Average Fuel Economy (CAFE) regulations are focusing on improving energy through reduced fuel consumption and greenhouse gas emissions. This work investigates the potential of a CO₂ capture system downstream of an aftertreatment system for a heavy-duty engine application. Amine absorption has been described as one of the most effective ways to capture CO₂ from the exhaust for point sources. Therefore, using thermal-swing absorption process with potassium carbonate (K₂CO₃) as the absorbent liquid, a process was analyzed …

A New Technique To Determine Accommodation Coefficients Of Cryogenic Propellants, Kishan Bellur

Dissertations, Master's Theses and Master's Reports

The control of propellant boil-off is essential in long-term space missions. However, a clear understanding of cryogenic propellant phase change and the values of accommodation coefficients are lacking. To that effect, a new method to determine accommodation coefficients using a combination of neutron imaging, thin film evaporation modeling and CFD modeling has been established. Phase change experiments were conducted in the BT-2 Neutron Imaging Facility at the National Institute of Standards and Technology (NIST) by introducing cryogenic vapor (H2 and CH4) at a set pressure into Al6061 and SS316L test cells placed inside a 70mm cryostat. Condensation is achieved by …

Pyrolysis Of Fiber-Plastic Waste Blends, Shreyas Kolapkar

Dissertations, Master's Theses and Master's Reports

The main objective of this work is to investigate fast pyrolysis of fiber and plastic feedstocks in order to understand the synergistic effect from their co-pyrolysis. In this on-going work, fiber, plastic and their blend are characterized and pyrolysis oil is produced from them in the fast batch pyrolysis reactor. Based on a heat transfer model it is shown that results of oil produced from batch reactor will be applicable to the continuous paddle reactor. From feedstock characterization, chlorine was observed particularly in the plastic feedstock. Thus, chlorine removal method using torrefaction and high shear mixing was implemented and was …

Thermomagnetic Convective Cooling Of Hall Effect Thruster, Elizabeth M. Vanheusden

Dissertations, Master's Theses and Master's Reports

This work proposes and shows that thermomagnetic convection could be used in zero gravity to cool components of a Hall-effect thruster. A ferrofluid cavity was develop in the thermal and geometric model of a Hall-effect thruster. Simulations show that with an Ionic Liquid Ferrofluid after two minutes of thruster operations thermomagnetic convection occurs and in zero gravity will produce a larger velocity then natural convection that occurs in earth gravity. However, experiments did not result in heat transfer enhancement due to the limitation of the ferrofluid. Replacement of the Ferrotec EFH1 dispersant with dodecylbenzene did not result in Ionic Liquid …

Experimental And Computational Investigation Of Dual Fuel Diesel- Natural Gas Rcci Combustion In A Heavy-Duty Diesel Engine, Mufaddel Dahodwala

Dissertations, Master's Theses and Master's Reports

Among the various alternative fuels, natural gas is considered as a leading candidate for heavy-duty applications due to its availability and applicability in conventional internal combustion diesel engines. Compared to their diesel counterparts natural gas fueled spark-ignited engines have a lower power density, reduced low-end torque capability, limited altitude performance, and ammonia emissions downstream of the three-way catalyst. The dual fuel diesel/natural gas engine does not suffer with the performance limitations of the spark-ignited concept due to the flexibility of switching between different fueling modes. Considerable research has already been conducted to understand the combustion behavior of dual fuel diesel/natural …

Analysis Of Injection Parameters Influencing Gasoline Direct Injection Compression Ignition (Gdici) Engine Operation In Ltc Using Naphtha, Devyani Patil

Dissertations, Master's Theses and Master's Reports

A multi-dimensional CFD study using MTU-KIVA-Geq-CHEMKIN code has been carried out for direct injection compression ignition engine combustion fueled with heavy naphtha, light naphtha, and PRF50 in low-temperature combustion (LTC) regime. At constant fueling, combustion characteristics are investigated as a function of injection timing and injection pressure. Further, operating limits of fuel confined by combustion efficiency, noise level (Maximum Pressure rise rate) and emissions at exhaust valve opening (EVO) are evaluated using parametric variation of initial gas temperature, exhaust gas recirculation fraction, boost pressure. Research conducted focuses on ability of fuel to get good combustion which is combustion efficiency > / …

Cold Start Analysis And Modeling Of A Direct-Injection Gasoline Engine, Yash Borghate

Dissertations, Master's Theses and Master's Reports

In this thesis, two different works related to cold start of a direct-injection (DI) gasoline engine are shown. First, effect of split injection is studied on engine exhaust temperature and hydrocarbon emissions for cold start conditions. Instead of single injection, two injections are done, one injection during the intake stroke and one injection during the compression stroke. Split injection is known to reduce jet wall wetting, thus reducing the hydrocarbon emissions from engine itself. Further, split injection reduces engine cycle-by-cycle variability with respect to the single injection case. Correlations between start of injection for the injection in the intake stroke …

Capillary-Assisted Enhanced Condensation Heat Transfer For Low Surface Tension Liquids, Gnana Vishnu Durgam

Dissertations, Master's Theses and Master's Reports

Extensive research has been carried out over the course of the last few decades to induce dropwise condensation as it offers 5 - 7 times better heat transfer performance compared to filmwise condensation process. A number of methods such as low surface energy hydrophobic coatings, surface modification of hydrophobic surfaces to fabricate micro, nano and hierarchical structures, and the recent incorporation of jumping droplet phenomenon have provided effective means to further enhance the condensation heat transfer. However, existing methods to enhance condensation heat transfer rate fail in the case of low surface tension, highly wetting liquids such as hydrocarbons, cryogens, …

Experimental Investigation Of Impinged Droplet Dynamics, Nitisha Ahuja

Dissertations, Master's Theses and Master's Reports

The fuel spray wall interaction phenomenon plays an essential role in determining the emissions and performance of an internal combustion engine. The investigation of single droplet wall interaction is crucial to understanding of a spray wall impingement process. This report is a compilation of the experimental work done to understand the droplet impingement characteristics, through optical diagnostics and temperature measurement. Different fuels and different surface under ambient and elevated temperature conditions are used for these tests, with two objectives: Development of a common depositionsplashing criteria; and Understanding droplet post impingement dynamics variation with factors like: Weber number (ratio of inertia …