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BioSim is a simulation tool which captures many basic life support functions in an integrated simulation. Conventional analyses can not efficiently consider all possible life support system configurations. Heuristic approaches are a possible alternative. In an effort to demonstrate efficacy, a validating experiment was designed to compare the configurational optima discovered by heuristic approaches and an analytical approach. Thus far, it is clear that a genetic algorithm finds reasonable optima, although an improved fitness function is required. Further, despite a tight analytical fit to data, optimization produces disparate results which will require further validation.

Biodiesel fuel can be produced from a wide range of source materials that affect the properties of the fuel. The diesel engine has become a highly tuned power source that is sensitive to these properties. The objectives of this research were to measure and predict the key properties of biodiesel produced from a broad range of source materials to be used as inputs for combustion modeling; and second to compare the results of the model with and without the biodiesel fuel definition. Substantial differences in viscosity, surface tension, density and thermal conductivity were obtained relative to reference diesel fuels and among the different source materials. The combustion model revealed differences in the temperature and emissions of biodiesel when compared to reference diesel fuel.

An optically accessible single-cylinder high-speed direct-injection (HSDI) Diesel engine equipped with a Bosch common rail injection system was used to study the spray and combustion processes for European low sulfur diesel, bio-diesel, and their blends at different blending ratio. Influences of injection timing and fuel type on liquid fuel evolution and combustion characteristics were investigated under similar loads. The in-cylinder pressure was measured and the heat release rate was calculated. High-speed Mie-scattering technique was employed to visualize the liquid distribution and evolution. High-speed combustion video was also captured for all the studied cases using the same frame rate. NOx emissions were measured in the exhaust pipe. The experimental results indicated that for all of the conditions the heat release rate was dominated by a premixed combustion pattern and the heat release rate peak became smaller with injection timing retardation for all test fuels.

Biodiesel fuels and their blends with diesel are often used to reduce emissions from diesel engines. However, biodiesel has been shown to increase the NOx emissions. Operating a compression ignition engine in low-temperature combustion mode as well as using multiple injections can reduce NOx emissions. Experimental data for biodiesel are compared to those for diesel to show the effect of the biodiesel on the peak pressure, temperature, and emissions. Accurate prediction of biodiesel properties, combined with the KIVA 3V code, is used to investigate the combustion of biodiesel. The volume fraction of the cylinder that has temperatures greater than 2200 K is shown to directly affect the production of oxides of nitrogen. Biodiesel is shown to burn faster during the combustion events, though the ignition delay is often longer for biodiesel compared to diesel.

A numerical study of micro-explosion in multi-component droplets is presented. The homogeneous nucleation theory is used in describing the bubble generation process. A modified Rayleigh equation is then used to calculate the bubble growth rate. The breakup criterion is then determined by applying a linear stability analysis on the bubble-droplet system. After the explosion/breakup, the atomization characteristics, including Sauter mean radius and averaged velocity of the secondary droplets, are calculated from conservation equations. Micro-explosion can be enhanced by introducing biodiesel into the fuel blends of ethanol and tetradecane. Micro-explosion is more likely to occur at high ambient pressure. However, increasing the ambient temperature does not have a significant effect on micro-explosion. There exists an optimal composition in the liquid mixture for micro-explosion.

An experimental study was performed at the University of Illinois at Urbana-Champaign Low-Speed Wind Tunnel to quantify the performance and flowfield effects of two-element open-wheel-race-car front wing configurations. Four distinct configurations were tested in- and out-of-ground effect and at various speeds (Reynolds numbers), angles of attack, and flap positions. A splitter plate was installed in the wind tunnel to act as the ground plane. Data presented include balance force measurements, surface pressure data, and downstream flow measurements using a seven-hole probe. Results show that these elementary factors in the design of race-car front wings have a significant effect on wing performance and behavior of the downstream flowfield.

The operation of a small bore high speed direct injection (HSDI) engine with a MVCO injector is simulated by the KIVA 3V code, developed by Los Alamos National Laboratory. The MVCO injector extends the range of injection timings over conventional injectors and it extra flexibility in designing injection schemes. Combustion from very early injection is observed with MVCO injections but not with conventional injection. This improves the fuel economy of the engine in terms of lower ISFC. Even better efficiency can be achieved by using biodiesel, which may be due to extra oxygen in the fuel improving the combustion process. Biodiesel sees a longer ignition delay for the initial injection. It also exhibits a faster burning rate and shorter combustion duration. Biodiesel also lowered both NOx and soot emissions. This is consistent with the general observation for soot emissions.

The KIVA-3V code, developed by Los Alamos National Laboratory, with modifications that improve its capability with biodiesel simulations was used to model the operation of an HSDI engine using blends of soybean biodiesel and diesel. Biodiesel and their blends with diesel are frequently used to reduce emissions from diesel engines, although previous studies showed that biodiesel may increase NOx emission. The paradox may be resolved by running the engine in low temperature combustion mode with biodiesel/diesel blends, as low temperature combustion simultaneously reduced NOx and soot. The modified KIVA code predicts the major combustion characteristics: peak combustion pressure, heat release rate and ignition timing accurately when compared with experimental measurements. It also correctly predicts the trend of NOx emissions. It was observed that the cylinder temperature distribution has a strong effect on emission levels.

The use of substances other than petroleum based fuels for power sources is not a new concept. Prior to the advent of petroleum fueled vehicles numerous other substances were used to create mobile sources of power. As the world's petroleum supply dwindles, alternative fuel sources are sought after to replace petroleum fuels. Many industries are particularly interested in the development of renewable fuel sources, or biologically derived fuel sources, which includes ethanol. The use of No. 2 diesel as well as many alternative fuels in compression ignition engines result in injector coking. Injector coking can severely limit engine performance by limiting the amount of fuel delivered to the combustion chamber and altering the spray pattern. Injector tip coking is also one of the most sensitive measures of diesel fuel quality [1]. A machine vision system was implemented to quantify injector coking accumulation when a compression ignition engine was fueled with oxydiesel.

Past research on airfoil and wing aerodynamics in icing are reviewed. This review emphasizes the periods after the 1978 NASA Lewis workshop that initiated the modern icing research program at NASA and the current period after the 1994 ATR accident where aerodynamics research has been more aircraft safety focused. Research pre-1978 is also briefly reviewed. Following this review, our current knowledge of iced airfoil aerodynamics is presented from a flowfield-physics perspective. This section identifies four classes of ice accretions: roughness, rime ice, horn ice, and spanwise ridge ice. In these sections the key flowfield features such as flowfield separation and reattachment are reviewed and how these contribute to the known aerodynamic effects of these ice shapes. Finally Reynolds number and Mach number effects on iced-airfoil aerodynamics are briefly summarized.

This paper examines the feasibility of modifying an existing semi-trailer air suspension system to function as an anti-rollover system in addition to its normal suspension operation. The semi-trailer model used is a dynamic, two-dimensional system. The anti-rollover system controller is formulated using projective control theory. All other factors being equal, simulations show that use of the modified suspension system decreases the weight shift when the semi-trailer undergoes lateral acceleration. By decreasing weight shift, the modified suspension system decreases the possibility of rollover.

The detailed mechanisms by which oxygenated diesel fuels reduce engine-out soot emissions are not well understood. The literature contains conflicting results as to whether a fuel's overall oxygen content is the only important parameter in determining its soot-reduction potential, or if oxygenate molecular structure or other variables also play significant roles. To begin to resolve this controversy, experiments were conducted at a 1200-rpm, moderate-load operating condition using a modern-technology, 4-stroke, heavy-duty DI diesel engine with optical access. Images of broadband natural luminosity (i.e., light emission without spectral filtering) from the combustion chamber, coupled with heat-release and efficiency analyses, are presented for three test-fuels. One test-fuel (denoted GE80) was oxygenated with tri-propylene glycol methyl ether; the second (denoted BM88) was oxygenated with di-butyl maleate. The overall oxygen contents of these two fuels were matched at 26% by weight.

This paper presents a programmable E/H control valve consisting of five individually proportional flow control valves. With a hybrid control algorithm, this valve has programmable valve characteristics, such as adjustable valve deadband and flow control gain, and programmable valve functions, such as different center functions. System analyses and experimental evaluations indicate that this programmable valve is capable of replacing conventional E/H control valves in practical applications.

Low aspect ratio wings are used extensively on open-wheeled race cars to generate aerodynamic downforce. Consequently, a great deal of effort is invested in obtaining wing profiles that provide high values of lift coefficient. If the wings are designed using 2-D methods, then it is necessary to take into account the change in operating angle of a typical airfoil section that occurs when it operates in the downwash generated by the wing. Accounting for this change during the design phase will ensure that the airfoil sections are optimized for their intended operating conditions. The addition of endplates to the wing serves to counteract the magnitude of the change in operating angle by effectively producing an increase in wing aspect ratio. During the design process at UIUC, an empirical method was used to provide an estimate of the effective aspect ratio of the wing and endplate combination.

The ability to categorize, compare and segregate the roll dynamical behavior of various vehicles from one another is a subject of considerable research interest. A number of comparison paradigms have been developed (static stability index, roll couple methods, etc.), but all suffer from lack of robustness: results developed on the basis of a particular comparison metric are often not able to be generalized across vehicle lines and types, etc., or they simply do not segregate vehicles at all. In addition, most models do not describe vehicle dynamics in sufficient detail, and some contain no dynamics at all (e.g., static stability index = t/2h). In the present work, static stability index, a two-degree-of-freedom roll model and a three-degree-of-freedom roll and handling model were used to locate eigenvalues for a sample of 43 vehicles consisting of (1) passenger cars, (2) light trucks, (3) sport/utility vehicles and (4) minivans.

Bio-butanol has been widely investigated as a promising alternative fuel. However, the main issues preventing the industrial-scale production of butanol is its relatively low production efficiency and high cost of production. Acetone-butanol-ethanol (ABE), the intermediate product in the ABE fermentation process for producing bio-butanol, has attracted a lot of interest as an alternative fuel because it not only preserves the advantages of oxygenated fuels, but also lowers the cost of fuel recovery for individual component during fermentation. If ABE could be directly used for clean combustion, the separation costs would be eliminated which save an enormous amount of time and money in the production chain of bio-butanol.

Bio-butanol has been considered as a promising alternative fuel for internal combustion engines due to its advantageous physicochemical properties. However, the further development of bio-butanol is inhibited by its high recovery cost and low production efficiency. Hence, the goal of this study is to evaluate two upstream products from different fermentation processes of bio-butanol, namely acetone-butanol-ethanol (ABE) and isopropanol-butanol-ethanol (IBE), as alternative fuels for diesel. The experimental comparison is conducted on a single-cylinder and common-rail diesel engine under various main injection timings (MIT) and equivalent engine load (EEL) conditions. The experimental results show that ABE and IBE significantly affect the combustion phasing. The start of combustion (SOC) is retarded when ABE and IBE are mixed with diesel. Furthermore, the ABE/IBE-diesel blends are more sensitive to the changes in MIT compared with that of pure diesel.

Biodiesel is a widely used biofuel in diesel engines, which is of particular interest as a renewable fuel because it possesses the similar properties as the diesel fuel. The pure soybean biodiesel was tested in an optical constant volume combustion chamber using natural flame luminosity and forward illumination light extinction (FILE) methods to explore the combustion process and soot distribution at various ambient temperatures (800 K and 1000 K) and oxygen concentrations (21%, 16%, 10.5%). Results indicated that, with a lower ambient temperature, the autoignition delay became longer for all three oxygen concentrations and more ambient air was entrained by spray jet and more fuel was burnt by premixed combustion. With less ambient oxygen concentration, the heat release rate showed not only a longer ignition delay but also longer combustion duration.

The formation of fuel film in the combustion cylinder affects the mixing process of the air and the fuel, and the process of the combustion propagation in engines. Some models of film evaporation have been developed to predict the evaporation behavior of the film, but rarely experimental results have been produced, especially when the temperature is high. In this study, the evaporation behavior of the film of different species of oil and their blends at different temperature are observed. The 45 μL films of isooctane, 1-propanol, 1-butanol, 1-pentanol, and their blends were placed on a quartz glass substrate in the closed temperature-controlled chamber. The shape change of the film during evaporation was monitored by a high-speed camera through the window of the chamber. First, the binary blends film of isooctane and one of the other three oils were evaporated at 30 °C, 50 °C, 70 °C and 90 °C.

An efficient multi-component fuel droplet vaporization model has been developed in this work using discrete approach. The precise modeling of droplet vaporization process is divided into two parts: vapor-phase and liquid-phase sub-models. Temporal evolution of flow inside the droplet is considered to describe the transient behavior introduced by the slow diffusion process. In order to account for the internal circulation motion, surface regression and finite diffusion without actually resolving the spatial governing equations within the liquid phase, a set of ordinary differential equations is applied to describe the evolution of the non-uniform distributions of universal diffusional variables, i.e. temperature and species mass fraction. The differences between the droplet surface and bulk mean states are modeled by constructing a quasi-1D frame; the effect of the internal circulations is taken into consideration by using the effective diffusivity rather than physical diffusivity.