Supervision: Metin Muradoglu

Start: Fall 2025

Duration: 3 years

Funding: Scientific and Technological Research Council of Türkiye (TUBITAK)

Requirements: Strong interest in fluid mechanics, turbulent flows, multiphase flows. Knowledge and experience in programming with a high-level language such as Fortran, C and C++, and familiarity with parallelization and high-performance computing are a big plus.

Summary: Droplet evaporation plays a crucial role in many industrial and natural processes such as spray combustion, food processing, spread of respiratory diseases, and cloud formation. Computational modeling of droplet evaporation is a challenging task due to continuous mass and energy exchange through evolving droplet-gas interface. Droplet evaporation in a convective environment makes the problem more complicated. Moreover, the Stefan flow, which arises due to the significant density change at the liquid-gas interface, can substantially alter the behavior of evaporating droplets, and its effect is amplified by an increase in the evaporation rate. Surfactant contamination adds a further complexity to this already highly complicated problem. It is generally infeasible to perform interface-resolved simulations of sprays and droplet clouds of practical importance due to prohibitively large computational requirements. Thus, large-scale spray simulations are usually carried out using point-particle methods where droplets are represented as point particles and low order models are employed for mass and energy transfer between droplets and the ambient gas. The current evaporation models involve gross assumptions and simplifications and thus perform unsatisfactorily in many practical applications. The conventional evaporation models are usually based on the boundary layer theory over the spherical droplet and do not consider the effects of droplet deformability, flow separation and wake behind the droplet, and surfactant contamination. Therefore, the performance of evaporation models needs to be assessed in detail against interface resolved simulation to improve their performance. More importantly, as the exiting models are old and somewhat outdated, it is pressing to develop new evaporation models in the light of detailed computational analysis.

In this project we aim to develop a high-fidelity numerical method for interface-resolved simulations of droplet evaporation and employ it to critically study the droplet evaporation under various conditions including convection and surfactant contamination, assess the performance of the exiting evaporation models, and improve/develop new low order evaporation models to be used in large scale spray simulations.