Statistics of Two-phase Coupling in Turbulent Spherically Expanding Flames in Mono-sized Fuel-droplet Mists

ABSTRACT

The statistics of flame–droplet interaction have been investigated for spherically expanding spray flames based on a three-dimensional DNS database. The source terms due to two-phase coupling arising from droplet evaporation in different governing equations for the gaseous carrier phase are considered to examine the effects of droplet diameter and overall (i.e. liquid+gaseous) equivalence ratio on the interaction between liquid and gaseous phases. Larger droplets are found to show higher probabilities of having greater values of slip velocity, and this behavior has been found to be unaffected by the overall equivalence ratio. Droplet diameter and number density have been found to significantly affect the interaction between liquid and gaseous phases since smaller droplets with overall fuel-lean equivalence ratio rarely interact with the flame in the reaction zone. Furthermore, source terms associated with the coupling between liquid and gaseous phases significantly contribute to mass, momentum, energy and mixture fraction transport equations. However, the contribution of droplet evaporation is relatively weak for the reaction progress variable transport equation.

KEYWORDS:

• Droplet combustion
• spherically expanding flame
• direct numerical simulations

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The financial support of the Republic of Turkey Ministry of National Education and EPSRC (EP/K025163/1 and EP/R029369/1) and the computational support of Rocket and ARCHER are gratefully acknowledged.