91̽»¨

Abstract:

A technique has been developed for full bore imaging, and a high speed video camera used to obtain images that have been processed for soot temperature and loading, and flame growth. The soot measurements have been made with a colour ratio technique that avoids the need for an in-situ absolute radiation calibration. Instead, the spectral response of the camera has to be determined for each of the red, green and blue channels. Planar Laser-Induced Fluorescence (PLIF) has been extensively used for visualizing species of combustion and reacting flows. However, the relationship between PLIF signal strength and species concentration is complicated by other dependencies, so careful calibration is essential. In order to study the effects of evaporation of a multi-component fuel in an IC engine, a gasoline-like component fuel has been devised which has three components of low, medium and high-volatility. Each component is made from two non-fluorescing constituents chosen so that the component (as a whole) will co-evaporate with one of three selected tracers: namely acetone, toluene or 1,2,4-trimethylbenzene (TMB). Calibration results are presented along with fuel concentration distributions derived from the PLIF images that have been analyzed on a cycle-by-cycle basis. © IMechE 2007.

Abstract:

Multi-mode absorption spectroscopy, MUMAS, in the near-infra-red is reported for the first time. A diode laser pumped Er/Yb:glass micro-cavity laser emitting multiple longitudinal modes at 1.53 microm was used to detect several transitions in the nu(1)+nu(3) overtone band of C2H2.

Abstract:

The use of multi-mode absorption spectroscopy (MUMAS) to detect multiple transitions in the A-band b(1)Sigma(g) (+)-X-3 Sigma(-)(g) of molecular oxygen is reported. The modelling of MUMAS signatures and the procedure for fitting such model signatures to experimental data obtained using a multi-mode diode laser is described. The technique is shown to allow accurate and precise measurement of concentration, temperature over the range 300 to 500 K and of pressure over the range 0.2 to 1 bar. Extension of the technique to other ranges of temperature and pressure and to other species is discussed.