The use of a noble gas as an inert tracer for mixing studies in combustion systems is investigated. Simultaneous two-photon laser-induced fluorescence (LIF) of krypton and Rayleigh scattering are used for imaging measurements of mixture fraction and temperature in turbulent non-premixed jet flames. The turbulent flames investigated in this study include a piloted CH4/air flame (Sandia flame D) ...

Synthesis and characterization of long wavelength visible-light absorption Cu-doped TiO2 nanomaterials with well-controlled properties such as size, composition, morphology, and crystal phase have been demonstrated in a single-step flame aerosol reactor. This has been feasible by a detailed understanding of the formation and growth of nanoparticles in the high-temperature flame region. The impo...

A means of performing simultaneous, high-speed measurements of temperature and OH lifetime-corrected laser-induced fluorescence (LIF) for tracking unsteady flames has been developed and demonstrated. The system uses the frequency-doubled and frequency-tripled output beams of an 80 MHz mode-locked Ti:sapphire laser to achieve ultrashort laser pulses (order 2 ps) for Rayleigh-scattering thermomet...

Three-dimensional direct numerical simulation of lean premixed hydrogen flames is used to explore the influence of species and thermal diffusion and viscosity on the flame structure and turbulent flame response. The leadingorder flame response is shown to be due to the global Lewis number with little influence from the other species. The previously-reported observation of decorrelation of fuel ...

In this work we present a numerical iterative procedure for the evaluation of the effect of signal absorption in two-color laser-induced incandescence (2C-LII) measurements. The correction process is applied to experimental results, previously published by our group, in an axisymmetric diffusion flame. We have studied the influence of signal trapping on peak soot temperature and on soot volume ...

Sensitivity analysis is one of the most widely used tools in kinetic modeling. Typically, it is performed by perturbing the A-factors of the individual reaction rate coefficients and monitoring the effect of these perturbations on the observables of interest. However, the sensitivity coefficients obtained in this manner do not contain any information on possible temperature dependent effects. Y...

A study of the ignition of non-fire-resistant hydraulic fluid sprays was conducted by the National Institute for Occupational Safety and Health. Both an open flame and a hot steel surface were used as the external heat sources. With the open flame as the heat source, the minimum oil temperature and minimum spray nozzle pressure that resulted in an ignition were measured. The effects of the dist...

Introduction A hydrocarbon flame can naturally and readily provide an appropriate high-temperature environment with abundant radical concentrations required for the growth of carbon nanotubes (CNTs) [1] or carbon nano-onions (CNOs) [2]. Therefore, flame synthesis shows a more promising potential for inexpensive and mass production of high-purity carbon nanostructures than other synthesis method...

Raman spectroscopy is applied to diagnose nanoparticle presence and characteristics in a gaseous flow field. Specifically, in situ monitoring of the Raman-active modes of TiO2 and Al2O3 nanoparticles in aerosol form is demonstrated in high-temperature flame environments. This technique serves as a sensitive and reliable way to characterize particle composition and crystallinity (e.g. anatase ve...

A series of large-scale experiments were performed to measure heat transfer to a massive cylindrical calorimeter engulfed in a 30-minute circular-pool fire. The calorimeter inner surface temperature and the flame black body emissive power were measured at several locations as functions of time. An inverse conduction technique was used to determine the net heat flux to the calorimeter. Light win...