A Rapid Compression Machine for Chemical Kinetics Studies at Elevated Pressures and Temperatures
A rapid compression machine (RCM) has been designed and fabricated for the purpose of chemical kinetics studies at elevated pressures and temperatures. The present RCM is pneumatically driven and hydraulically actuated and stopped. Stroke of the machine varies from 7 to 10 inches and clearance is also adjustable. Compression ratio of up to 21 can be obtained. The optically-accessible reaction chamber is equipped with sensors for the measurements of pressure and temperature. In addition, a rapid sampling apparatus is incorporated in the reaction chamber for determining species concentration at specific post-compression time. A deliberately machined crevice on the cylindrical surface of the piston has been optimized, using STAR-CD CFD package, in order to suppress the formation of the roll-up vortex and provide a homogeneous core of reaction mixture. Temperature mapping using planar laser induced fluorescence of acetone shows that roll-up vortex is indeed suppressed by using the present creviced piston. Experiments with either inert gases or reactive mixtures demonstrate the reproducibility of pressure traces. Compression process is also shown to be very rapid and free from any significant mechanical vibrations. Measurements show that highly repeatable compressed conditions of up to 50 bar and greater than 1000 K can be obtained. A numerical model accounting for heat loss is also developed to simulate the RCM data. This work documents the design and operation of the present RCM as well as establishes its suitability for combustion studies.
Combustion Science and Technology
Mittal, Gaurav and Sung, Chih-Jen, "A Rapid Compression Machine for Chemical Kinetics Studies at Elevated Pressures and Temperatures" (2007). Mechanical Engineering Faculty Research. 712.