Velocity and Turbulence Measurements in a Combustion Chamber of S. I. Engine under Motored and Firing Operations by L. D. A. with Fiber-Optic Pick-Up

870166

02/01/1987

Event
SAE International Congress and Exposition
Authors Abstract
Content
In order to improve adaptability of the laser Doppler anemometer (LDA) to measurement of gas flow velocities in an internal combustion engine, an optical fiber system composed of a couple of single mode, polarization-preserving optical fibers has been developed to transmit the incident beams. The overall light transmission efficiency of the system is 24 % and not so high, but the system enables real-time measurements of gas flow velocity in the combustion chamber of a small two-cycle engine during firing operation.
The velocity data measured are processed with cycle by cycle analysis by stationary time-averaged method to obtain bulk velocity Ū, turbulence intensity u′ and integral time scale of turbulence Lt. The results indicate that Ū varies very much depending on motored and firing operations due to the expansion flow of combustion, accompanying a new flow field formation, and that u′ is about twice and Lt is 40 - 50 % higher during combustion period than the respective values during the same period of motored operation.
Meta TagsDetails
DOI
https://doi.org/10.4271/870166
Pages
20
Citation
Obokata, T., Hanada, N., and Kurabayashi, T., "Velocity and Turbulence Measurements in a Combustion Chamber of S. I. Engine under Motored and Firing Operations by L. D. A. with Fiber-Optic Pick-Up," SAE Technical Paper 870166, 1987, https://doi.org/10.4271/870166.
Additional Details
Publisher
Published
Feb 1, 1987
Product Code
870166
Content Type
Technical Paper
Language
English