Aerosol Shock Tube Designed for Ignition Delay Time Measurements of Low-Vapor-Pressure Fuels and Auto-Ignition Flow-Field Visualization

• Published in: Energies (Basel) Vol. 13; no. 3; p. 683
• Main Authors: Liu, Erwei, Liao, Qin, Xu, Shengli
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2020
• Subjects: aerosol shock tube; Aerosols; Atomizing; auto-ignition flow-field visualization; Cameras; Charge coupled devices; Decomposition; Delay time; Droplets; Flow; Gases; Hydrocarbons; Ignition; ignition delay time; Laboratories; Nozzles; Particle size; Photomultiplier tubes; Polymethyl methacrylate; Premixing; Pressure; Pressure sensors; Sauter mean diameter; Spontaneous combustion; Steel pipes; Toluene; Vapors; Visualization
• DOI: 10.3390/en13030683
• ISSN: 1996-1073

An aerosol shock tube has been developed for measuring the ignition delay times (tig) 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 μ m at pressures of 0.14–0.19 MPa of dilute gases. In the case of a stoichiometric mixture of toluene/O2/N2, 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/T. In contrast to the reference data, ignition delay times of aerosol toluene/O2/N2 were generally larger. Sequential images of auto-ignition flow-field showed the features of flame from generation to propagation.