Atomization Models

The LISA Atomization model simulates a pressure-swirl atomizer.
The Huh Atomization model simulates a simple hole injector.

The LISA Atomization Model

The Linearized Instability Sheet Atomization (LISA) model is a primary atomization model for the thin liquid sheet at nozzle exit created by the action of a pressure-swirl atomizer. This model corresponds to the LISA model node in the Lagrangian phase model tree, and selecting it activates the Nozzle Injector type for injectors. The model generates initial size and velocity values for droplets entering through the injectors active for the Lagrangian phase, as described in the formulation.


Theory	LISA Model
Provided By	[physics continuum] > Models > Lagrangian Multiphase > [phase] > Models > Primary Atomization
Example Node Path	Continua > Physics 1 > Models > Lagrangian Multiphase > Phase 1 > Models > LISA Atomization
Requires	Optional Models: Lagrangian Multiphase From Lagrangian Multiphase > Lagrangian Phases > [phase] > Models: Particle Type: Material Particles Material: Liquid or Multi-Component Liquid
Activates	Materials	See Materials and Methods.
	Field Functions	Droplet Dynamic Viscosity Droplet Surface Tension

The Huh Atomization Model

The Huh Atomization Model is a primary atomization model that simulates the disintegration process of a liquid jet exiting from a hole-type injector at high speed. This model estimates the initial perturbations from an analysis of the flow through the nozzle and then uses established wave growth theory, together with other hypotheses, to represent the atomization process. This model corresponds to the Huh Atomization model node in the Lagrangian phase model tree, and selecting it activates the Nozzle Injector type for injectors. The Huh model assumes an initial droplet size equal to the nozzle diameter; droplet velocity and subsequent breakup is modeled as described in the formulation.


Theory	Huh Model
Provided By	[physics continuum] > Models > Lagrangian Multiphase > [phase] > Models > Primary Atomization
Example Node Path	Continua > Physics 1 > Models > Lagrangian Multiphase > Phase 1 > Models > Huh Atomization
Requires	Optional Models: Lagrangian Multiphase From Lagrangian Multiphase > Lagrangian Phases > [phase] > Models: Particle Type: Material Particles Material: Liquid or Multi-Component Liquid
Activates	Materials	See Materials and Methods.
	Field Functions	Droplet Dynamic Viscosity Droplet Surface Tension Droplet Weber Number Primary Atomization Status
Properties	See below.

Huh Atomization Model Properties

C1: Atomization length scale coefficient, $C_{1}$ used to define $κ$ in Eqn. (3085). The default value is 2.0.
C2: Wave length scale coefficient, $C_{2}$ used to define $κ$ in Eqn. (3085). The default value is 0.5.
C3: Spontaneous time scale coefficient, $C_{3}$ in Eqn. (3086). The default value is 1.0.
C4: Exponential time scale coefficient, $C_{4}$ in Eqn. (3086). The default value is 1.5.
CA1: Turbulence time scale coefficient, $C_{a 1}$ in Eqn. (3083) and Eqn. (3084). The default value is 0.92.
CA2: Turbulence length scale coefficient, $C_{a 2}$ in Eqn. (3083). The default value is 0.4565.
KA: Droplet breakup rate coefficient, $K_{A}$ in Eqn. (3087). The default value is 0.1.
Normal Velocity Coefficient: Controls the radial diffusion of the spray; $K_{3}$ in Eqn. (3118). The larger it is, the more rapid the radial diffusion of the spray. The default value is 0.
WeCrit: The critical Weber number ${W e}_{c r}$ . For the Huh model, the Weber number is given by Eqn. (3079). If $W e < {W e}_{c r}$ , the injected parcel bypasses the primary atomization process and proceeds directly to the secondary breakup process, if activated. The default value is 12.0.

Materials and Methods

The LISA and Huh Atomization models activate the following material properties under Lagrangian Phases > [phase] > Models > Liquid or Multi-Component Liquid:

Dynamic Viscosity

Dimensions: The dimensionality of the viscosity (read-only).
Method: Constant or Field Function.

Surface Tension

Dimensions: The dimensionality of the surface tension (read-only).
Method: Constant or Field Function.