PRELIMINARY STUDIES OF AUTOIGNITION AND FLASHBACK IN A PREMIXING-PRE VAPORIZING FLAME TUBE USING JET-A FUEL AT LEAN EQUIVALENCE RATIOS

摘要

Autoignition delay times are reported for a premixing-prevaporizing tube operated with liquid Jet-A fuel. Lean equivalence ratios ranged from 0.3 to 0.7. Combustor inlet air pressures were varied from 0.54 to 2.5 MPa, combustor inlet air temperatures from 550 to 700 K, and reference velocities from 8 to 35 meters per second. Autoignition delay times ranged from 15 to 100 milliseconds and varied inversely with pressure. The Arrhenius activation energy was 41 840 joules per mole (10 000 cal/mole). Temperature rise data were obtained in a long premixing-prevaporizing tube at a pressure of 0.56 MPa. Preflame temperature rise data were a function of equivalence ratio, inlet air temperature, and tube residence time. Significant temperature rise occurred above temperatures of 760 K, with autoignition occurring at 775 K for equivalence ratios greater than 0.47. The reactions were similar to cool-flame phenomena. Flashback velocities were measured at temperatures of 610 and 700 K, a pressure of 0.56 MPa and equivalence ratios from 0.6 to 1. Flashback velocities varied from 30 to 65 meters per second.