Vaporization, Mixing, and Ignition Dynamics in High-Pressure Evaporating and Reacting Sprays
Abstract
The objective of the proposed research is to investigate vaporization, gas-phase mixing, and ignition dynamics in evaporating (non-reacting) and reacting sprays at high pressures and high temperatures. State-of-the art laser-based diagnostics are to be used for (i) analyzing the coupling between liquid droplets and the gas phase during vaporization and how this governs the structure of the fuel vapor-ambient mixing field, (ii) characterizing the effects of injection (pressure, mass, and duration) and operating conditions (ambient pressure and temperature) on gas-phase mixing topology, (iii) examining CH2O (low-temperature species) concentration fields, the correlation with the liquid spray and gas-phase mixing topology, and the dependence on injection and operating conditions, and (iv) providing new information regarding the role of low-temperature (first-stage) ignition and mixing dynamics on the onset high-temperature ignition. A major target is the measurement of a series of conditional statistics that detail the most probable mixture composition for facilitating ignition and the correlation between low-temperature species such as CH2O and the onset of high-temperature, second-stage ignition. Some fundamental questions to be answered include: (i) Where does vaporization occur in relation to the liquid spray plume, i.e., what is the correlation between fuel vapor (and vapor-ambient mixtures) and liquid droplet position? How does this change as a function of liquid mass injection and ambient density? (ii) When (time following fuel injection) and where (with respect to the liquid spray plume) do lower-temperature species such as CH2O form? What fuel vapor conditions are highly correlated with CH2O formation? (iii) What is the spatial structure of the CH2O field following fuel injection and how does it evolve during the induction period leading to second-stage ignition? What is the correlation between the local CH2O fluctuations and the equivalence ratio field? (iv) When and where (spatial location) does second-stage ignition occur? What are the most probable mixing (local equivalence ratio) conditions supporting ÒhotÓ ignition? (v) Does high-temperature ignition occur in regions of high CH2O concentrations (i.e., regions of fuel pyrolysis and partial oxidation) or regions with high CH2O gradients, indicating an importance in species transport and cool flame propagation?
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810086
Entities
People
- Jeffrey A Sutton
Organizations
- Army Contracting Command
- Ohio State University
- United States Army