Evaporation and clustering of ammonia droplets in a hot environment

Angelilli, Lorenzo; Pérez, Francisco E. Hernández; Im, Hong G.; Ciottoli, Pietro Paolo; Valorani, Mauro

doi:10.1103/physrevfluids.7.114301

Cited by 11 publications

(3 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where F d is the aerodynamic drag force and F g is the gravity force, ṁevap 2)-( 4) are outside the scope of this work. Interested readers can find the details in [4,5,8,[25][26][27][28].…”

Section: Numerical Modelmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of droplet evaporation dynamics using computational singular perturbation and tangential stretching rate

Angelilli,

Galassi,

Ciottoli

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

Computational singular perturbation (CSP) has been successfully used in the analysis of complex chemically reacting flows by systematically identifying the intrinsic timescales and slow invariant manifolds that capture the essential subprocesses driving the dynamics of the system. In this article, the analytical and computational framework is applied for the first time to analyze the Lagrangian droplets undergoing evaporation and dispersion in the surrounding gases. First, a rigorous mathematical formulation is derived to adapt the CSP tools into the droplet dynamics equations, including the formal definition of the tangential stretching rate (TSR) that represents the explosive/dissipative nature of the system. A steady ammonia and a falling water droplet studies are then conducted to demonstrate the utility of the CSP methodology in identifying various physical mechanisms driving the evolution of the system, such as the distinction of thermal-driven and mass-driven regimes. Various definitions of the importance indices are also examined to provide in-depth analysis of different subprocesses and their interactions in modifying the droplet dynamics.

show abstract

Section: Numerical Modelmentioning

confidence: 99%

“…An accurate description of the fundamental characteristics of break-up, dispersion, and evaporation is essential for designing effective combustion systems. Such a high-fidelity spray model can improve the fidelity of engineering simulations in the Reynolds-average Navier-Stokes (RANS) [4,5] or large eddy simulations (LES) [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Analysis of droplet evaporation dynamics using computational singular perturbation and tangential stretching rate

Angelilli,

Galassi,

Ciottoli

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Beroun et al tested LPG injection in the intake manifold of an engine and explained that the extreme low temperature generated in the spray caused injector tip icing [28]. Angelilli et al noticed that liquid ammonia also has a cooling effect because of its large latent heat, preventing droplets from boiling in hot environments [29]. Ainsalo et al compared the spray characteristics of liquid propane with other conventional liquid fuels [30].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of High-Pressure Liquid Ammonia Injection under Non-Flash Boiling and Flash Boiling Conditions

Fang

Zhang

et al. 2023

Energies

View full text Add to dashboard Cite

Liquid ammonia is an ideal zero-carbon fuel for internal combustion engines. High-pressure injection is a key technology in organizing ammonia combustion. Characteristics of high-pressure liquid ammonia injection is lack of research. Spray behaviors are likely to change when a high-pressure diesel injector uses liquid ammonia as its fuel. This study uses high-speed imaging with a DBI method to investigate the liquid penetration, width, and spray tip velocity of high-pressure liquid ammonia injection up to 100 MPa. Non-flash and flash boiling conditions were included in the experimental conditions. Simulation was also used to evaluate the results. In non-flash boiling conditions, the Hiroyasu model provided better accuracy than the Siebers model. In flash boiling conditions, a phenomenon was found that liquid penetration and spray tip velocity were strongly suppressed in the initial stage of the injection process, this being the “spray resistance phenomenon”. The “spray resistance phenomenon” was observed when ambient pressure was below 0.7 MPa during 0–0.05 ms ASOI and was highly related to the superheated degree. The shape of near-nozzle sprays abruptly changed at 0.05 ms ASOI, indicating that strong cavitation inside the nozzle caused by needle lift effects is the key reason for the “spray resistance phenomenon”.

show abstract