Scalar field measurements in reciprocating engines

Air-Fuel Mixture Characteristics of Reciprocating Engines

“…Centre-line results for nozzles A and C (Figures 3 and 4) show increased mixing and spread of the injected fuel with a bowl-lip piston geometry and the convergent (spray-type) nozzle (C) and a similar increase was found with a flat piston by Green and Whitelaw (1987). The bowl-lip piston with nozzle A (Figure 3a (Figure 3b), the centre-line of X'IX;, rises quickly from 6 percent to a maximum of around 12.5 percent and decreases gradually to around 10 percent near the piston.…”

“…Control of the fuel injection and timing synchronisation was carried out in the manner described by Green and Whitelaw (1987). The injection characteristics are presented in Table II and give rise to exit velocities for each nozzle as summarised in Table III together with the corresponding Reynolds numbers (Re), area ratios (A*) and time constants for the nozzles with Reynolds numbers based on the nozzle exit diameter and Freon-12 density at the in-cylinder conditions at the time of fuel injection.…”

“…The measurement uncertainties and sources of error in the Rayleigh scattering measurements for the time varying density field in the four-stroke engine have been examined by Green and Whitelaw (1987). To minimise the interference of dust particle scattering on the LRS signal, the intake air was passed through a filtering system which removed particles greater than 0.5 .urn before entering the engine cylinder.…”

“…The in-cylinder mole fraction distribution of Freon-12 was measured with the laser Rayleigh scattering system described by Green and Whitelaw (1987). A line diagram of the optical arrangement and signal instrumentation is shown in Figure 2.…”

“…Photography has provided useful information of simulated Diesel sprays, for example Tishkoff et al (1982) and Bracco (1985), but quantitative measurements of the instantaneous scalar properties in the cylinders of reciprocating engines remain to be obtained. Attempts to obtain such measurements using laser-excited fluorescence, Raman spectroscopy and laser Rayleigh scattering have been reported by Smith (1980), Cole and Swords (1980) and Green and Whitelaw (1987), but the emphasis has been on technique development. Efforts involving the study of turbulent combustion in engines using combined laser techniques have been reported on by Witze and Dyer (1986).…”