Ignition of a Liquid Fuel under High Intensity Radiation.
Abstract
The time sequence of behavior of liquid fuel and of the fuel vapor near the liquid surface during the laser-induced ignition period was observed by high speed schlieren and direct photography. A CW carbon dioxide laser with fluxes up to 2500 watts per square centimeter was used; beam incident angles were 30 and 90 degrees with respect to the liquid surface. Both n-decane and l-decene were used as the liquid fuel. The pictures reveal, in time sequence, the formation of a radial wave, a central surface depression, bubble nucleation/growth/bursting followed by complex surface motion and further bubbling; typically several (or many) bubble cycles preceded ignition. Effects of laser flux level, incident laser angle and absorption coefficient of the liquid on the formation of bubbles, the size of bubbles, the frequency of bubble formation and the vaporization process are studied. A feasibility study of the use of two-wavelength holographic interferometry to measure vapor concentration and its temperature during the ignition period has been undertaken. The design of a system to measure infrared absorption coefficients of liquid vapor at elevated temperatures was completed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1980
- Accession Number
- ADA095691
Entities
People
- Takashi Kashiwagi
- Thomas J. Ohlemiller
Organizations
- National Institute of Standards and Technology