The extinction of a dilute spray flame burning in a steady, one-dimensional, low-speed, sufficiently off-stoichiometric, two-phase flow, and experiencing the external heat transfer from the spray to a tube wall upstream is further analyzed. The external heat transfer results in globally external heat loss, excess enthalpy burning and external heat gain, respectively, to the spray system with increasing the wall temperature. However, the droplet gasification provides the overall internal heat loss and heat gain for rich and lean sprays, respectively. Therefore, the burning and extinction of the dilute spray flame can be fully described by the interaction between external and internal heat transfers in two spray models which were identified to be the completely and partially prevaporized burnings. The C-shaped and S-shaped extinction curves are clearly classified and mapped with parameters of the wall temperature, the overall external heat transfer and the initial droplet size. Variations of the extinction curves under the influence of transition from overall external heat loss to heat gain, and the jump between the completely and partially prevaporized burnings on flame extinction, are reported and discussed for both lean and rich sprays.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes