Study of Hydrogen/Syngas Combustion and NO Emissions at High Pressures and Temperatures Yiguang Ju, Mechanical and Aerospace Engineering, Princeton University, D330, E-quad, Olden Street, Princeton, NJ 08544 Background: Power generation from hydrogen/syngas derived from coal and biomass with carbon capture and storage is a new technology to reduce CO2/NOx emissions. However, combustion properties and NOx emissions of hydrogen/syngas with CO2/N2 dilutions at high pressures and temperatures in gas turbine conditions have been rarely studied. Fundamental data of flame speeds and flame instability are urgently needed for the design of hydrogen/syngas gas turbine engines. Research goal: The goal of this study is to measure the flame speeds, flammability limits, and the NO emissions of hydrogen/syngas flames accurately, and to study the effects of N2 and CO2 dilution on NO formations at high pressures and temperatures. The purpose of the present study is to develop a rigorous method for accurate measurement of syngas flame speeds at high pressures and temperatures by using a spherical bomb. Achievements: Laminar flame speeds for syngas mixtures of various compositions up to 20 atm were measured with outwardly propagating spherical flames. A theoretic model to consider flow compression and flame geometry for accurate flame speed determination was developed. A time-accurate and front-adaptive numerical algorithm was developed to simulate the outwardly propagating spherical flame and to validate the kinetic mechanism. An accurate spectral dependent radiation model was developed to predict flame speed and flammability of mixtures by including radiation reabsorption at high pressures.