in this paper, the performance of a natural gas hcci engine is studied through a thermodynamic model including detailed chemical kinetics. it is shown that as hydroxyl radical has important effects on natural gas combustion, it is possible to quantify soc with hydroxyl concentration variations. meanwhile the influence of using formaldehyde as an additive on the engine characteristics has been i...

This paper simulates the density and temperature fields in the process of mixture formation with two combustion modes in a Diesel engine. The computational simulations and experiments show that in the normal combustion mode, the density and temperature of mixtures change greatly in the combusting sprays so that there are premixed combustion and diffusion combustion simultaneously, which results...

Large Eddy Simulation (LES) is applied to investigate the turbulent non-premixed combustion flow, including species concentrations and temperature, in a cylindrical combustor. Gaseous propane (C3H8) is injected through a circular nozzle which is attached at the centre of the combustor inlet. Preheated air with a temperature of 773K is supplied through the annulus surrounding of this fuel nozzle...

‘Thermal Overload’ can be defined as a condition under which design threshold values such as the surface temperature of combustion chamber components is exceeded. In this paper, a low λ value is identified as the most probable cause of voluminous flame production, resulting in high surface temperatures of engine components, i.e., engine thermal overload. Test results indicated that the flame be...

We report on the development and application of a broadband absorption spectrometer utilizing a pulsed supercontinuum laser light source and dispersion compensating fiber with a single-pass absorption path to obtain absolute methane mole fractions in a laminar nonpremixed CH(4)/air flame supported on a Wolfhard-Parker burner. The basic principle of supercontinuum broadband absorption spectrosco...

Based on tunable diode laser absorption spectroscopy (TDLAS), two-dimensional (2D) distribution reconstructions of gas concentration and temperature are realized using an algebraic reconstruction technique (ART). The influence of the beam distribution and grid size on combustion field reconstruction is investigated to attain optimal reconstruction results with a limited number of beams. Under l...

We demonstrate hybrid femtosecond/picosecond (fs/ps) coherent anti-Stokes Raman scattering for high-speed thermometry in unsteady high-temperature flames, including successful comparisons with a time- and frequency-resolved theoretical model. After excitation of the N(2) vibrational manifold with 100 fs broadband pump and Stokes beams, the Raman coherence is probed using a frequency-narrowed 2....

The e ect of initial nonequilibrium dissociated air constituents on the combustion of hydrogen in highspeed ows for a simulated Mach 17 ight condition was investigated by analyzing the results of comparative combustion experiments performed in a re ected shock tunnel test gas and in a shock expansion tunnel test gas. The results were analyzed and interpreted with a one-dimensional quasi-three-s...

The TOVS Path-B data set provides atmospheric temperature and water vapor profiles as well as cloud properties over the globe, from 1987 to 1995. Their relatively high spectral resolution yields reliable cirrus properties, day and night. First, we present average cirrus properties and their seasonal and diurnal variations. A reanalysis which will extend the present data set back to 1979 and up ...

There are many incentives to increase the fuel efficiency of combustion processes. This paper looks at two available options to achieve this goal. The former aims to develop an experimental method that can analyze combustion at extremely high pressures to improve the understanding of high pressure H2/air combustion. Experimental data has been lacking a suitable combustion diagnostic to visualiz...