We explore the detailed structure of heat release and the energy budget for a freely-propagating lean, premixed hydrogen flame. At lean conditions, the flame is thermodiffusively unstable and spontaneously develops the cellular burning structures, characteristic of this type of flame. The instabilities in the system saturate quickly, resulting in robust, slowly evolving cellular burning feature...

The objective of this work was to investigate the influence of preferential diffusion on flame structure and propagation of lean-premixed hydrogen-carbon monoxide syngas-air flame at elevated pressure using direct numerical simulation (DNS) and detailed chemistry. The physical problem investigated is lean-premixed H2/CO outwardly propagating turbulent spherical flame at constant pressure of 4ba...

Combustion under high-pressure conditions holds the potential for improved thermodynamic efficiency, enhanced power generation, and reduced emission of some pollutants. It underlies the technology of internal combustion engines such as the automotive engine, the gas turbine, and the rocket engine, for which the operating pressure can reach as high as 100s atm. At such high-pressure conditions, ...

China is one of the largest producers and users of brominated flame retardants (BFRs) in the world. This has led to ubiquitous environmental occurrence of the main BFRs commercially available in China, namely polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and tetrabromobisphenol A (TBBPA). Wastewater from BFR manufacturing, manufacturing of BFR-based products, and e-wa...

We study the dynamics and properties of a turbulent flame, formed in the presence of subsonic, high-speed, homogeneous, isotropic Kolmogorov-type turbulence in an unconfined system. Direct numerical simulations are performed with Athena-RFX, a massively parallel, fully compressible, high-order, dimensionally unsplit, reactive-flow code. A simplified reaction-diffusion model represents a stoichi...

A time-based injection module for monosegmented continuous flow systems and related techniques, which uses three independently controlled solenoid valves, is described. A timer c'cuit employing three LC. 555s and three TIP-121 transistors was constructed to control the injection module valves. The injection device was tested with non-reacting chemical systems (for example with a spectro-photome...

An ethylene-air laminar diffusion flame successfully provided silicon substrates of anodic aluminum oxide (AAO) template with vertically oriented well-aligned carbon nanotubes. Field emission scanning electron microscopy (SEM) showed that open-tipped carbon nanotubes consisting of tube elements with the same length and diameter uniformly coated the template. High-resolution transmission electro...

Vanadium is found in many rocks and minerals, including asphaltite. Asphaltite is one of the naturally occurring black, solid bitumens, which are soluble at heating in carbon disulfide and fuse. Asphaltite is also a solidified hydrocarbon compound derived from petroleum. Determination of vanadium in asphaltite ash was performed by microwave-acid digestion followed by inductively coupled plasma-...

A flow injection system for the potassium speciation in fortified wines, using two detectors placed in series, is described. The free, or ionized form, is monitored in a tubular-shaped potassium ion-selective electrode, and the total potassium content in a flame emission spectrometer used as end-of-line detector. Potassium determinations can be carried out in a linear range from 300 to 2000 mg ...

A flame shape descriptor based on coordinates of edge of a flame is proposed. Artificial Neural Network is used to predict flame image edges .A flame with constant x-coordinate is used in the present study. Y-coordinates of flame edge are predicted using neural network. Recognition experiments were carried out using flame image sampled from a burning candle. The results show a good recognition ...