In this paper, we present a detailed experimental study of turbulence chemistry interactions in the ‘‘DLR_B’’ turbulent jet diffusion flame. The flame operates on mixtures of CH4, H2, and N2 in the fuel stream at Re = 22,800 and is a target flame within the TNF workshop. Extinction and re-ignition events can be tracked in real time and related to the underlying flow field phenomena and temperat...

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...

A novel approach to simultaneously measure the translational temperature, bulk velocity, and density in gases by collecting, referencing, and analyzing nanosecond time-scale Rayleigh scattered light from molecules is described. A narrow-band pulsed laser source is used to probe two largely separated measurement locations, one of which is used for reference. The elastically scattered photons con...

Combustion instabilities in gas turbine has been a major setback in the quest for efficient and clean combustion. Accurate characterisation and prediction of these disturbances is required to suppress them either at the design stage or in a close loop control when the system is in operation. The use of flame transfer functions has been a common approach in different literatures. Flame temperatu...

Premixed methane-air mixture is introduced at the center of two parallel circular quartz plates separated by a millimeter scale distance (<or= 5mm). Two plates are heated with an external heater to create a positive temperature gradient condition along the flow direction. The combustion characteristics of lean methane-air mixtures are investigated at phi=0.67 and phi=0.85 in the laminar flow re...

Compared with conventional camera, the light field camera takes the advantage of being capable of recording the direction and intensity information of each ray projected onto the CCD (charge couple device) sensor simultaneously. In this paper, a novel method is proposed for reconstructing three-dimensional (3-D) temperature field of a flame based on a single light field camera. A radiative imag...

Melt flow and dripping of the pyrolysing polymer melt can be both a benefit and a detriment during a fire. In several small-scale fire tests addressing the ignition of a defined specimen with a small ignition source, well-adjusted melt flow and dripping are usually beneficial to pass the test. The presence of flame retardants often changes the melt viscosity crucially. The influence of certain ...

The development of flame ionization detection took place on an empirical basis without a clear understanding of the 1 mechanism. The study of flames by mass spectrometry showed that the all-important ion was the formylium ion CHO . The pre-combustion degradation was thought to be a pyrolytic degradation and hydrogenation at the high temperatures obtained close to the combustion zone. Using a ca...

A computational study was conducted on expanding spherical premixed flames to investigate the dynamics of flame-ball formation at elevated temperatures and pressures. Lean H2/air mixtures were investigated using a time-dependent, spherically symmetric code with detailed chemistry, transport, and radiation submodels. Results show that, with increasing pressure, both the steady-state flame-ball r...

Study of gas fuel temperature influence on combustion performance by means of numerical modeling is a main objective of this work. Combustion of a single jet of propane in a cross-flowing stream of preheated and oxygen deficient air is analyzed. Both Eddy-Break-Up and PDF/mixture fraction combustion models coupled with RNG k-ε turbulent model were applied and compared. Thermal and prompt NOx mo...