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The Parameter Signature Isolation Method And Applications, James Richard Mccusker

Open Access Dissertations

The aim of this research was to develop a method of system identification that would draw inspiration from the approach taken by human experts for simulation model tuning and validation. Human experts are able to utilize their natural pattern recognition ability to identify the various shape attributes, or signatures, of a time series from simulation model outputs. They can also intelligently and effectively perform tasks ranging from system identification to model validation. However, the feature extraction approach employed by them cannot be readily automated due to the difficulty in measuring shape attributes. In order to bridge the gap between the …

Modeling Of Flash Boiling Flows In Injectors With Gasoline-Ethanol Fuel Blends, Kshitij Deepak Neroorkar

Open Access Dissertations

Flash boiling may be defined as the finite-rate mechanism that governs phase change in a high temperature liquid that is depressurized below its vapor pressure. This is a transient and complicated phenomenon which has applications in many industries. The main focus of the current work is on modeling flash boiling in injectors used in engines operating on the principle of gasoline direct injection (GDI). These engines are prone to flash boiling due to the transfer of thermal energy to the fuel, combined with the sub-atmospheric pressures present in the cylinder during injection. Unlike cavitation, there is little tendency for the …

Modeling Of Thermal Non-Equilibrium In Superheated Injector Flows, Shivasubramanian Gopalakrishnan

Open Access Dissertations

Among the many factors that effect the atomization of a fuel spray in a com- bustion chamber, the flow characteristics of the fuel inside the injector nozzle play significant roles. The enthalpy of the entering fuel can be elevated such that it is higher than the local or downstream saturation enthalpy, which will result in the flash-boiling of the liquid. The phase change process dramatically effects the flow rate and has the potential to cause subsonic two-phase choking. The timescale over which this occurs is comparable to the flow-through time of the nozzle and hence any attempt to model this …

A Comprehensive Study Of The Extensional Rheology Of Complex Fluids, Manojkumar Chellamuthu

Doctoral Dissertations 1896 - February 2014

Non-Newtonian fluids play an important role in our daily life. The visco-elastic nature of these fluids comprises a class of materials found in variety of items ranging from food, to plastic products, to the cosmetic products. The design and tunability of non-Newtonian fluids is only possible through an understanding of their complex dynamics and rheology. In this thesis, a filament stretching rheometer is used to investigate the extensional rheology of three important classes of complex visco-elastic fluids namely surfactants, suspensions and polymers.

Surfactants with their unique molecular amphiphilic chemistry allow them to form long wormlike micellar structures, which behave like …

The Analytical Modeling Of The Thermometric Performance Of Total Temperature Thermocouple Probes, Leroy Bertram Butler

Open Access Dissertations

A total temperature thermocouple probe immersed in a moving gas stream undergoes thermal energy exchange by means of forced convection between the thermocouple wires and the flowing gas stream, conduction along the thermocouple wires to the probe mount, and radiation between the thermocouple junction wires and any surrounding structure. In general, the thermocouple junction does not indicate the true (stagnation) temperature of the gas stream, thus necessitating the calibration of total temperature probes to obtain correct temperature measurements.

Two models are developed to predict the temperature indicated by a total temperature probe (utilizing type K thermocouple wire) for a given …