Infrared measurements of soot formation and droplet sizes in diesel sprays. Final report, June 6, 1987--December 31, 1990
This report describes an investigation of diesel sprays using a combination of infrared wavelength optical diagnostics to probe the high droplet number density region surrounding the injector tip. Infrared wavelengths were shown to be more effective than visible or ultraviolet wavelength light at penetrating this region of the spray. This success is easily explained by the decrease in optical cross section of small diameter drops (less than 10 {mu}m) for a wavelength shift from the visible to wavelengths near 10 {mu}m. Two types of diagnostics were implemented. First, a custom manufactured, high speed infrared spectrometer was used to monitor the spectral region between 6 and 12 {mu}m in 0.5 {mu}m intervals. Spectra from this instrument, for specific locations in the combusting spray were used to monitor the development of soot in the spray. The second diagnostic technique used three collinear laser beams focussed into a 0.25 mm beam to monitor the droplet size in the spray. This measurement uses a ratio of signals to remove the droplet number density as a variable and the observed signal ratio is a direct indication of the average (using an approximate radius to the fourth power weighting function) droplet size. The experiments were performed using a shock tube to simulate the conditions typical of diesel combustion (700 to 900 K in temperature and approximately 3.0 MPa in pressure) and a custom manufactured single shot fuel injection system. Optical access in the shock tube included visible and infrared transmissive windows arranged to provide orthogonal access in two directions and perpendicular to the spray axis. The fuel injection system for this work was configured to produce approximately 20 MPa of injection pressure and produced a single injection approximately 2 ms after the injection trigger. This system could therefore be controlled to inject into the quiescent reflected region of the shock tube after the incident shock reflection from the end wall.
- Research Organization:
- Physical Sciences, Inc., Andover, MA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-87AL42881
- OSTI ID:
- 10152227
- Report Number(s):
- DOE/AL/42881--T1; PSI--1040/TR-1207; ON: DE94012308
- Country of Publication:
- United States
- Language:
- English
Similar Records
A constant volume diesel spray combustion facility and the corresponding experimental diagnostics
Engine combustion and flow diagnostics