Combustion characteristics of isolated sub-millimeter sized methyl butanoate (MB) droplets are studied at low gravity (10 4 m/s) in a 1.2 s drop tower. In the experiments, droplets were grown and deployed onto the intersection of two 14 lm silicon carbide fibers in a cross-string arrangement and exposed to symmetrically placed spark ignition sources. The initial droplet diameter was fixed at 0....

This work presents a study of non-premixed flames at supercritical-pressure conditions. Emphasis is placed on flame stability in liquid rocket engines fueled with liquid oxygen and gaseous hydrogen. The flame structure sensitivity to strain, pressure, temperature and real-fluid effects was investigated in detailed opposed-jet flames calculations. It is shown that the flame is very robust to str...

Turbulent combustion is an important process in many technical applications, e.g. industrial gas furnaces used for heating water, production of steam and combustion in jet and diesel engines. To control the turbulent combustion, simulation tools with predictive power are required. The basic equations for turbulent combustion are well known, but their application to the complex flows appearing i...

Stereo Imaging Velocimetry (SIV) is a NASA Glenn Research Center (GRC) developed fluid physics technique for measuring three-dimensional velocities in any optically transparent fluid that can be seeded with tracer particles. SIV provides a means to measure three-dimensional fluid velocities quantitatively and qualitatively at many points. This technique provides full-field 3–D analysis of any o...

We describe several laser fluorescence methods used to measure lead in flames and in post-flame gases. Each relies on excitation of the 7s P1 4 6p 2 3P0 transition from the ground state of lead and detection of fluorescence on the 7s P1 3 6p 2 P1 and 7s P1 3 6p 2 P2 transitions. Aqueous solutions of lead salts are atomized and injected into a lean flatflame. Dye laser excitation is used to dete...

A Rocket Based Combined Cycle combustor model is tested at a ground direct connected rig to investigate the flame holding characteristics with a small rocket exhaust using liquid kerosene. The total temperature and the Mach number of the vitiated air flow, at exit of the nozzle are 1505 K and 2.6, respectively. The rocket base is embedded in a fuel injecting strut and mounted in the center of t...

Enthalpy (fuel mass fraction and/or temperature) fluctuations in the oncoming mixture are known to have important impacts on premixed combustion and in particular on combustion instability. Theoretical modeling has primarily been following an empirical approach. In Part I of the present study, an asymptotically reduced first-principle theory was derived from the reactive Navier-Stokes equations...

The present work addresses unsteady flame dynamics in a lean-premixed swirl-stabilized combustor, with attention focused on the transition of flame structure from a stable to an unstable state. It was found that the inlet temperature and equivalence ratio are the two most important variables determining the stability characteristics of the combustor. A slight increase in the inlet mixture tempe...

MoO2 nanotube with rectangular cross sections can be prepared on Mo substrates by using an O2-C2H2 combustion-flame method [Jpn. J. Appl. Phys. 44 (2005) L449]. We have investigated the growth behavior of the nanotube in detail by using scanning electron microscopy and energy dispersive x-ray microanalysis. The precursor of the growth is produced onsite at the Mo substrate, through reactions wi...

Increasing requirements on the environmental acceptability of internal combustion engines led to strong efforts to meet the continuously getting stricter emission regulations. New concepts of combustion and injection have been developed together with appropriate techniques of exhaust gas aftertreatment. For diesel engines especially modern high pressure injection systems, such as the applicatio...