Darwin Arifin is a return graduate student visitor from the University of Colorado. He will be participating in experiments related to the production of hydrogen and carbon monoxide via thermochemical redox cycles of ceria and doped ceria. Such thermochemical cycles are a means to produce precursors to fungible fuels, and research during his visit will focus on materials that can be used in concentrated solar power applications.
Arkke Eskola arrived in October from the University of Helsinki to begin a postdoctoral term in the Laser Chemistry Laboratory with Craig Taatjes. His work will focus on understanding the detailed autoignition chemistry of small hydrocarbon fuels.
Andrea Gruber is working with Jackie Chen to collaboratively perform direct numerical simulation of turbulent reactive channel flow to investigate flame-wall interactions.
Reliable methods are needed to predict flame light-up boundaries that result from compressed hydrogen bulk storage leaks without complex modeling or experimentation. Although modelers can determine the likelihood that an ignition kernel will form within a jet region when an ignition source is present, current methods do not effectively measure of whether sustained flame light-up will occur. In addition to the pre-combustion mixture stoichiometry, ignition kernel growth also depends on the local flame speed vs. the flow strain rate along with turbulence-chemistry interactions. Information regarding these phenomena requires simultaneous measurements of concentration and velocity within the turbulent jet both prior to and after the ignition kernel has developed. Torben will acquire these measurements using simultaneous acetone PLIF and stereoscopic PIV diagnostics.
Evatt Hawkes will visit to discuss and work on collaborative research in the area of direct simulation (DNS) of turbulent combustion and model development of extinction and reignition in turbulent jet flames. Specifically, we will continue our collaborations on reactive scalar mixing, extinction and reignition, soot formation and transport in turbulent jet flames, premixed flame structure and models for flame stretch in the thin reaction zones regime, premixed flame-wall interactions, models for autoignition at high pressure under HCCI environments.
Prof. Alejandro Molina, from the National University of Colombia, at Medellín, arrived to work in the Char Combustion Lab at Sandia with Chris Shaddix. His work will focus on computational and experimental determination of the influence of gas transport properties on the oxy-fuel combustion of pulverized coal, for CO2 capture during electrical power production.
Yanqing Niu, a PhD student from Xi’an Jiatong University in Xi’an, China, began a year-long research visit with Chris Shaddix and postdoc Manfred Geier, working in the Char Combustion Laboratory. Yanqing’s research at Sandia will focus on development of a predictive model for ash effects on char combustion and on measurements of the combustion and gasification reactivity of torrefied biomass.
Adam Scheer is arriving from the University of Colorado in January 2012 to take up a postdoctoral position in the Laser Chemistry Laboratory with Craig Taatjes. His work will focus on experiments and modeling of biofuel ignition chemistry.
Manqi Zhu will perform her Master’s internship (Ecole Centrale in Beijing) at Sandia working on analysis of direct numerical simulation data and performing unsteady 1D counterflow flame simulations.
Francisco Briceño Sánchez, a Ph.D. student of Prof. José M. García Oliver from the CMT-Motores Térmicos located at Universitat Politécnica of Valencia in Spain, recently completed a three-month visit to the heavy-duty optical diesel engine laboratory, working with Mark Musculus. Francisco’s project focused on using three simultaneous optical diagnostics (laser-extinction, two-color pyrometry imaging, and laser-induced incandescence) to evaluate the relative performance of these diangostics under low-temperature combustion conditions. He returned to Spain at the end of October to complete his graduate degree.
Matthew Dunn left Sandia in December 2011 to start an academic appointment at his home institution of Sydney University, Australia after two and a half years working with Rob Barlow as a postdoc in the Turbulent Combustion Laboratory. A highlight of Matt’s contributions at the CRF was his development of a noise reduction scheme for Raman/Rayleigh/LIF based on wavelet analysis.
Alexandre Flügel was a visiting Ph.D. student from the Department of Thermodynamics at the University of Erlangen-Nürnberg in Germany. He worked with Hope Michelsen for 3 months to study soot formation and detection in counter-flow and co-flow diffusion flames.
Katie Gabet & Dirk Geyer
Katie Gabet, a PhD student of Prof Jeff Sutton at Ohio State, visited the CRF and Rob Barlow’s Turbulent Combustion Laboratory last summer to learn about our experimental techniques and methods of data analysis for Raman/Raleigh scattering measurement. This was part of an ongoing multi-institution collaboration to extend quantitative Raman scattering methods to flames of dimethyl ether (DME) and other C2 hydrocarbons. Dirk Geyer from the Technical University of Darmstadt, Germany also visited last summer to work with Rob Barlow and Isaac Ekoto on the Raman spectroscopy of these molecules.
Esteban Gonzalez, who worked for two years as a postdoctoral associate in the Reacting Flows Research Department developing turbulence simulation codes, recently left Sandia for a staff position at Combustion Science & Engineering, Inc. in Columbia, MD, where he does computational fluid dynamics research and engineering studies.
Franz Holzleithner, a PhD student from the Technical University of Vienna, Austria, worked with Chris Shaddix and postdoc Manfred Geier on the analysis of the ratio of CO to CO2 produced during the combustion of coal chars. This factor is critical to determining the temperature and burning rate of coal chars during their combustion. Franz has returned to Vienna to complete his PhD research on modeling the Corex coal gasification process.
Chris Polonowski worked as a post-doctoral researcher in the Heavy-Duty Optical Engine and Fuels Research Laboratory with PI Chuck Mueller. His work focused on using high fuel-injection pressures, small injector-orifice diameters, and fuel-property changes to achieve mixing-controlled diesel combustion that does not produce soot because it occurs at equivalence ratios less than approximately two. Chris left Sandia at the end of December 2011 to take a position as a research engineer with Ford Motor Company.
For a part of 2011, Romina Rodriguez worked as a student intern in the Alternative Fuels DISI Engine Lab with Magnus Sjoberg. Her work focused on setting up and validating a GT-Power model of the engine to well capture the engine breathing across wide ranges of engine speed and boost pressures. The work also included high-speed imaging and analysis of the valve motion to be used as an important input to the model. After the project at Sandia, Romina returned to UC-Berkeley to continue her Ph.D. studies.
Martin Schiemann, a PhD student from the Ruhr-University Bochum, one of the largest universities in Germany, worked in the Char Combustion Laboratory with Chris Shaddix and postdoc Manfred Geier. He performed optical pyrometry measurements of coal char combustion temperatures using the same coal chars as he has been investigating using an image-based pyrometry system in Prof. Viktor Scherer’s lab at Bochum. He has returned to Bochum to compare the measurements and data analysis procedures at Sandia with similar approaches being used in Germany.
Alexis Sevault, a PhD student from the Norwegian University of Science Technology, completed a six month visit in April 2011 as part of a collaboration with SINTEF to study oxy-fuel combustion. Alexis worked with Rob Barlow and Matt Dunn in the Turbulent Combustion Laboratory to obtain detailed scalar measurements in jet flames of CH4/H2 mixtures burning in a coflow of O2 and CO2.
Kwee-Yan Teh, a postdoc who worked with Andy Lutz and Chris Shaddix on energy analysis of biofuel production pathways, has departed Sandia to accept a lecturer position at the University of Michigan-Shanghai, in Shanghai, China.
Subith Vasu worked as a postdoctoral associate in the Laser Chemistry Laboratory with Craig Taatjes. He carried out experimental investigations of fundamental autoignition chemistry as part of an LDRD project on co-development of novel biofuels and combustion strategies. He has left Sandia to take an assistant professor position in the Department of Mechanical, Materials and Aerospace Engineering at the University of Central Florida.
Guanghua Wang, a former Sandia postdoc who is now at GE CRD, returned to the Turbulent Combustion Lab to conduct some exploratory line-imaged temperature measurements using thin filament pyrometry (TFP). Tests were conducted calibration burners, laminar jet flames, and turbulent jet flames that have been very well characterized using well established laser diagnostics.
Jiayao Zhang departed Sandia after working as a postdoc with Chris Shaddix on making laser-based measurements in sooty turbulent non-premixed jet flames and with Bob Schefer on hydrogen safety research. Yao has accepted an engineering design position with KLA-Tencor, a major Silicon Valley engineering firm.