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...

The dynamics of soot formation in turbulent ethylene–air nonpremixed counterflow flames is studied using direct numerical simulation (DNS) with a semi-empirical soot model and the discrete ordinate method (DOM) as a radiation solver. Transient characteristics of soot behavior are studies by a model problem of flame interaction with turbulence inflow at various intensities. The interaction betwe...

A swirling CH4/air diffusion flame at atmospheric pressure was stabilized in a gas turbine model combustor with good optical access. The investigated flame with a thermal power of 10 kW and an overall equivalence ratio of 0.75 exhibited pronounced thermoacoustic oscillations at a frequency of 295 Hz. The main goal of the presented work was a detailed experimental characterization of the flame b...

We analyze the structure of diffusion flames at high pressure in the limit of large activation energy for the particular configuration of a steady flame in counterflow. We consider the fluid to be near the thermodynamic critical point in which case the effective mass diffusivity is negligible, and Soret diffusion is the dominant mechanism for fuel mass transport. Temperature and species profile...

Original scientific paper In this paper, influence of flame spraying and fusing on microstructure of substrates made from heat treated carbon steel C45, a heat treated low alloyed 42CrMo4 steel and stainless austenitic steel X6CrNiMo18-10-2, has been investigated. Flame spraying and fusing is a deposition technique commonly applied to nickel-base self-fluxing alloys (NiCrBSi alloys). Because of...

Our objective is to characterize gravity effects on the structure of laminar methane–air partially premixed flames through detailed simulations. We examine the heat loss due to radiation from similar flames that are established at various gravitational accelerations and coflow velocities. Radiation is modeled using the optically thin assumption that provides a limiting value for the radiation h...

Hot surface ignition was examined using a variety of heat sources in a series of premixed hydrocarbon, hydrogen, and air mixtures. Building off previous work, hexane-air, heptane-air and hydrogen-air experiments were performed in addition to the eventual hexane-hydrogen-air mixtures. Using high-speed schlieren photography, thermocouples, and a fast-response pressure transducer, flame characteri...