Spark ignited turbulent flame kernel growth. Annual report, January--December 1991
An experimental study of the effect of spark power on the growth rate of spark-ignited flame kernels was conducted in a turbulent flow system at 1 atm, 300 K conditions. All measurements were made with premixed, propane-air at a fuel/air equivalence ratio of 0.93, with 0%, 8% or 14% dilution. Two flow conditions were studied: a low turbulence intensity case with a mean velocity of 1.25 m/sec and a turbulence intensity of 0.33 m/sec, and a high turbulence intensity case with a mean velocity of 1.04 m/sec and a turbulence intensity of 0.88 m/sec. The growth of the spark-ignited flame kernel was recorded over a time interval from 83 {mu}sec to 20 msec following the start of ignition using high speed laser shadowgraphy. In order to evaluate the effect of ignition spark power, tests were conducted with a long duration (ca 4 msec) inductive discharge ignition system with an average spark power of ca 14 watts and two short duration (ca 100 nsec) breakdown ignition systems with average spark powers of ca 6 {times} 10{sup 4} and ca 6 {times} 10{sup 5} watts. The results showed that increased spark power resulted in an increased growth rate, where the effect of short duration breakdown sparks was found to persist for times of the order of milliseconds. The effectiveness of increased spark power was found to be less at high turbulence and high dilution conditions. Increased spark power had a greater effect on the 0--5 mm burn time than on the 5--13 mm burn time, in part because of the effect of breakdown energy on the initial size of the flame kernel. And finally, when spark power was increased by shortening the spark duration while keeping the effective energy the same there was a significant increase in the misfire rate, however when the spark power was further increased by increasing the breakdown energy the misfire rate dropped to zero.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG04-90AL62353
- OSTI ID:
- 10161746
- Report Number(s):
- DOE/AL/62353-1; ON: DE94014214; BR: 35ED04000/ED3902000; TRN: AHC29414%%22
- Resource Relation:
- Other Information: PBD: Jun 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Spark ignited turbulent flame kernel growth. Annual report, January--December, 1992
Ignition flame kernel growth under simulated idle conditions