| Abstract: | A novel three-wavelength mid-infrared laser-based absorption/extinction diagnostic has been developed for simultaneous measurement
of temperature and vapor-phase mole fraction in an evaporating hydrocarbon fuel aerosol (vapor and liquid droplets). The measurement
technique was demonstrated for an n-decane aerosol with D
50∼3 μ
m in steady and shock-heated flows with a measurement bandwidth of 125 kHz. Laser wavelengths were selected from FTIR measurements
of the C–H stretching band of vapor and liquid n-decane near 3.4 μm (3000 cm
−1), and from modeled light scattering from droplets. Measurements were made for vapor mole fractions below 2.3 percent with
errors less than 10 percent, and simultaneous temperature measurements over the range 300 K<T<900 K were made with errors less than 3 percent. The measurement technique is designed to provide accurate values of temperature
and vapor mole fraction in evaporating polydispersed aerosols with small mean diameters (D
50<10 μ
m), where near-infrared laser-based scattering corrections are prone to error. |
