Argonne Researchers to Be Honored for "Best" Paper at an ASME Conference

On October 26, 2004, mechanical engineer Stephen Ciatti will receive an award from the American Society of Mechanical Engineers (ASME) for having given the best presentation at the 24th Conseil International des Machines a Combustion (CIMAC)/ASME World Congress on Combustion Engine Technology, in Kyoto, Japan, last June. The award ceremony will be held as a part of the banquet program at the ASME Internal Combustion Engine Division's 2004 Fall Technical Conference, in Long Beach, California.

Ciatti will accept the award on behalf of himself and his colleagues, researchers Chris Powell, Seong-Kyun Cheong, and Jinyuan Liu and Michigan Technological University professor Franz X. Tanner. Their paper, 'Comparison of X-Ray-Based Fuel Spray Measurements with Computer Simulation Using the CAB Model,' pinpointed the reason for discrepancies that had arisen between Argonne's X-ray measurements of diesel fuel spray profiles and optical measurements made by other research groups. This study is based on additional X-ray experiments at the Advanced Photon Source and computer simulations using the Cascade Atomization and Breakup (CAB) model.

The study showed that the discrepancies between the optical and X-ray experiments resulted from the use of fundamentally different definitions of fuel spray width. Optical methods, which rely on the scattering of visible light by fuel spray droplets, use a definition that depends on the reflective properties of the outer droplets in the spray. X-ray absorption measurements, by contrast, can penetrate the droplet sheath to make time-resolved measurements of the relatively dense core of the spray, and this increased capability is reflected in the way spray width is defined in this context. When the two definitions of spray width were applied in computer simulations with the CAB model, results agreeing with both sets of measurements were obtained, indicating that the definitions themselves were the distinguishing factor.

The importance of the paper derives ultimately from the importance of fuel injection to the operation of diesel engines. Fuel spray characteristics are crucial to engine performance and the emissions released to the atmosphere. Fuel spray measurements of those characteristics, in turn, are fundamental to modeling how fuel injectors work. Therefore, it is vital that the differences between these measurement techniques are understood and communicated to the research community.