| Summary: | An aerosol shock tube has been developed for measuring the ignition delay times (<i>t</i><sub>ig</sub>) of aerosol mixtures of low-vapor-pressure fuels and for visualization of the auto-ignition flow-field. The aerosol mixture was formed in a premixing tank through an atomizing nozzle. Condensation and adsorption of suspended droplets were not observed significantly in the premixing tank and test section. A particle size analyzer was used to measure the Sauter mean diameter (SMD) of the aerosol droplets. Three pressure sensors and a photomultiplier were used to detect local pressure and OH emission respectively. Intensified charge-coupled device cameras were used to capture sequential images of the auto-ignition flow-field. The results indicated that stable and uniform aerosol could be obtained by this kind of atomizing method and gas distribution system. The averaged SMD for droplets of toluene ranged from 2 to 5 <inline-formula> <math display="inline"> <semantics> <mi mathvariant="sans-serif">μ</mi> </semantics> </math> </inline-formula>m at pressures of 0.14−0.19 MPa of dilute gases. In the case of a stoichiometric mixture of toluene/O<sub>2</sub>/N<sub>2</sub>, ignition delay times ranged from 77 to 1330 μs at pressures of 0.1−0.3 MPa, temperatures of 1432−1716 K and equivalence ratios of 0.5−1.5. The logarithm of ignition delay times was approximately linearly correlated to 1000/<i>T</i>. In contrast to the reference data, ignition delay times of aerosol toluene/O<sub>2</sub>/N<sub>2</sub> were generally larger. Sequential images of auto-ignition flow-field showed the features of flame from generation to propagation.
|
|---|
