Dropletparticle

Dropletparticle is a term used in fluid dynamics and aerosol science to describe a discrete liquid droplet represented as a single computational particle within a carrier-phase flow. In Eulerian-Lagrangian simulations, each dropletparticle tracks its own position, velocity, and properties, while the surrounding gas is treated as a continuous field.

A dropletparticle is characterized by its diameter (or radius), mass, temperature, and composition. Evaporation is commonly modeled by mass and energy transfer equations, which cause the particle size to shrink as vapor diffuses away. Depending on volatility, droplets may fully evaporate, condense, or reach a state of thermodynamic equilibrium with the carrier phase.

Dynamics: The trajectory of a dropletparticle is influenced by gravity, drag, buoyancy, and possibly lift forces in sheared or turbulent flows. Turbulence can be modeled by stochastic or deterministic methods; for very small droplets Brownian motion may be included. Correlations with the carrier phase and effects of turbulence are important for dispersion.

Interactions and coupling: Dropletparticles may undergo coagulation, breakup, or collisions with surfaces, leading to deposition. In higher mass-loading scenarios, two-way coupling exchanges momentum and energy between the droplets and the gas.

Applications: Modeling sprays in combustion and engines, spray cooling, inkjet printing, spray drying, agricultural aerosol applications, and atmospheric science.

Modeling approaches: Point-particle or discrete-particle methods treat droplets as zero-size points with subgrid-scale physics for evaporation and drag; finite-size or corrections handle limits where particle size affects flow. The choice depends on the Reynolds number, droplet size, and computational resources.