EvaporationModelKnight< number, number_2 > Class Template Reference

Developer Documentation: MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 > Class Template Reference

Developer Documentation

This class implements the evaporative mass flux and temperature jump for rapid evaporation according to Knight's theory. More...

#include <evaporation_model_knight.hpp>

Public Member Functions
	EvaporationModelKnight (const number atmospheric_pressure, const number boiling_temperature_at_atmospheric_pressure, const number latent_heat_of_evaporation, const number specific_gas_constant, const number specific_heat_ratio_vapor)
	Constructor.

void	reinit (const number_2 &T_liquid, const number_2 &Ma_gas, const unsigned int n_active_lanes=dealii::VectorizedArray< number >::size())
	Use Knight's theory to evaluate the current evaporative mass flux and temperature jump T_liquid - T_gas.

number_2	get_evaporative_mass_flux () const
	Getter function for the evaporative mass flux.

number_2	get_temperature_jump () const
	Getter function for the temperature jump T_liquid - T_gas.

Private Member Functions
number_2	compute_temperature_ratio (const number_2 &m_g) const
	Calculate the temperature ratio T_gas/T_sat according to Knight's theory.

number_2	compute_density_ratio (const number_2 &T_gas_over_T_sat, const number_2 &m_g, const number_2 &exp_m_g_2, const number_2 &erfc_m_g) const
	Calculate the density ratio rho_gas/rho_sat according to Knight's theory.

number_2	compute_factor_beta (const number_2 &T_gas_over_T_sat, const number_2 &rho_gas_over_rho_sat, const number_2 &m_g, const number_2 &exp_m_g_2) const
	Calculate the factor beta according to Knight's theory.

void	apply_boiling_threshold (const number_2 &T_sat)
	Restrict evaporation to liquid temperatures above the boiling temperature.

Private Attributes
const number	atmospheric_pressure
	Atmospheric pressure in the gas phase (gas chamber pressure)

const number	boiling_temperature_at_atmospheric_pressure
	Boiling temperature of the considered material at atmospheric pressure conditions.

const number	latent_heat_of_evaporation
	Latent heat of evaporation.

const number	specific_gas_constant
	Specific gas constant.

const number	specific_heat_ratio_vapor
	Ratio of specific heats for the vapor phase.

const number	temperature_constant
	Temperature constant for Clausius-Clapeyron equation.

const number	helper_mass_flux
	Precomputed helper variable for the mass flux computation.

const number	helper_temperature_ratio
	Precomputed helper variable for the temperature ratio computation.

number_2	evaporative_mass_flux {}
	Evaporative mass flux from Knight's theory.

number_2	temperature_jump {}
	Temperature jump from Knight's theory.

Detailed Description

template<typename number, typename number_2 = number>
class MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >

This class implements the evaporative mass flux and temperature jump for rapid evaporation according to Knight's theory.

Knight, C. J. (1979). Theoretical modeling of rapid surface vaporization with back pressure. AIAA journal, 17(5), 519-523. DOI: 10.2514/3.61164

It is derived from kinetic gas theory and couples the liquid and gaseous phase in a thermodynamically consistent way.

Template Parameters

number	Floating point type.
number_2	A vectorized array data type can be passed as second template parameter, that is used for vectorized computation.

Note: By default, number_2 is set to the given floating point type number.; Currently, a monoatomic ideal gas is assumed. In addition, the material is assumed to consist of one species with averaged material properties. No component-wise evaporation behavior is considered for alloys.

Constructor & Destructor Documentation

◆ EvaporationModelKnight()

template<typename number , typename number_2 >

MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::EvaporationModelKnight	(	const number	atmospheric_pressure,
		const number	boiling_temperature_at_atmospheric_pressure,
		const number	latent_heat_of_evaporation,
		const number	specific_gas_constant,
		const number	specific_heat_ratio_vapor
	)

explicit

Constructor.

Parameters

atmospheric_pressure	Atmospheric pressure in the gas phase (gas chamber pressure).
boiling_temperature_at_atmospheric_pressure	Boiling temperature of the considered material at atmospheric pressure conditions.
latent_heat_of_evaporation	Latent heat of evaporation.
specific_gas_constant	Specific gas constant.
specific_heat_ratio_vapor	Ratio of specific heats for the vapor phase.

Member Function Documentation

◆ apply_boiling_threshold()

template<typename number , typename number_2 >

void MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::apply_boiling_threshold ( const number_2 & T_sat )

private

Restrict evaporation to liquid temperatures above the boiling temperature.

This function simply sets the evaporative_mass_flux and temperature_jump to zero, if the liquid surface temperature T_sat is below the boiling temperature.

Parameters

T_sat Saturated vapor temperature at liquid surface (=liquid surface temperature).

◆ compute_density_ratio()

template<typename number , typename number_2 >

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::compute_density_ratio	(	const number_2 &	T_gas_over_T_sat,
		const number_2 &	m_g,
		const number_2 &	exp_m_g_2,
		const number_2 &	erfc_m_g
	)		const

private

Calculate the density ratio rho_gas/rho_sat according to Knight's theory.

Parameters

T_gas_over_T_sat	Temperature ratio T_gas/T_sat.
m_g	Dimensionless gas velocity.
exp_m_g_2	Precomputed exponential of the squared dimensionless gas velocity `m_g`.
erfc_m_g	Precomputed complementary error function of the dimensionless gas velocity `m_g`.

Returns: Density ratio rho_gas/rho_sat.

◆ compute_factor_beta()

template<typename number , typename number_2 >

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::compute_factor_beta	(	const number_2 &	T_gas_over_T_sat,
		const number_2 &	rho_gas_over_rho_sat,
		const number_2 &	m_g,
		const number_2 &	exp_m_g_2
	)		const

private

Calculate the factor beta according to Knight's theory.

This factor corresponds to the amount of back-scattered atoms in the Knudsen layer. It can be determined from kinetic gas theory.

Parameters

T_gas_over_T_sat	Temperature ratio T_gas/T_sat.
rho_gas_over_rho_sat	Density ratio rho_gas/rho_sat.
m_g	Dimensionless velocity.
exp_m_g_2	Precomputed exponential of the squared dimensionless velocity `m_g`.

Returns: Factor beta.

◆ compute_temperature_ratio()

template<typename number , typename number_2 >

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::compute_temperature_ratio ( const number_2 & m_g ) const

private

Calculate the temperature ratio T_gas/T_sat according to Knight's theory.

Parameters

m_g	Dimensionless gas velocity.

Returns: Temperature ratio T_gas/T_sat.

◆ get_evaporative_mass_flux()

template<typename number , typename number_2 = number>

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::get_evaporative_mass_flux ( ) const

inline

Getter function for the evaporative mass flux.

Returns: Evaporative mass flux.

◆ get_temperature_jump()

template<typename number , typename number_2 = number>

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::get_temperature_jump ( ) const

inline

Getter function for the temperature jump T_liquid - T_gas.

Returns: Temperature jump T_liquid - T_gas.

◆ reinit()

template<typename number , typename number_2 >

void MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::reinit	(	const number_2 &	T_liquid,
		const number_2 &	Ma_gas,
		const unsigned int	n_active_lanes = `dealii::VectorizedArray<number>::size()`
	)

Use Knight's theory to evaluate the current evaporative mass flux and temperature jump T_liquid - T_gas.

Parameters

T_liquid	Current liquid surface temperature.
Ma_gas	Current Mach number in the gas phase at interface position.
n_active_lanes	Number of active lanes in the VectorizedArray.

Note: This function just updates the current values for the evaporative mass flux and temperature jump. Use the provided getter functions for access. Make sure to properly call this function before you apply the getter functions for mass flux and temperature jump.

Member Data Documentation

◆ atmospheric_pressure

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::atmospheric_pressure

private

Atmospheric pressure in the gas phase (gas chamber pressure)

◆ boiling_temperature_at_atmospheric_pressure

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::boiling_temperature_at_atmospheric_pressure

private

Boiling temperature of the considered material at atmospheric pressure conditions.

◆ evaporative_mass_flux

template<typename number , typename number_2 = number>

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::evaporative_mass_flux {}

private

Evaporative mass flux from Knight's theory.

◆ helper_mass_flux

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::helper_mass_flux

private

Precomputed helper variable for the mass flux computation.

◆ helper_temperature_ratio

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::helper_temperature_ratio

private

Precomputed helper variable for the temperature ratio computation.

◆ latent_heat_of_evaporation

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::latent_heat_of_evaporation

private

Latent heat of evaporation.

◆ specific_gas_constant

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::specific_gas_constant

private

Specific gas constant.

◆ specific_heat_ratio_vapor

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::specific_heat_ratio_vapor

private

Ratio of specific heats for the vapor phase.

◆ temperature_constant

template<typename number , typename number_2 = number>

const number MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::temperature_constant

private

Temperature constant for Clausius-Clapeyron equation.

◆ temperature_jump

template<typename number , typename number_2 = number>

number_2 MeltPoolDG::Evaporation::EvaporationModelKnight< number, number_2 >::temperature_jump {}

private

Temperature jump from Knight's theory.

The documentation for this class was generated from the following files:

include/meltpooldg/phase_change/evaporation_model_knight.hpp
source/phase_change/evaporation_model_knight.cpp

EvaporationModelKnight&lt; number, number_2 &gt; Class Template Reference

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ EvaporationModelKnight()

Member Function Documentation

◆ apply_boiling_threshold()

◆ compute_density_ratio()

◆ compute_factor_beta()

◆ compute_temperature_ratio()

◆ get_evaporative_mass_flux()

◆ get_temperature_jump()

◆ reinit()

Member Data Documentation

◆ atmospheric_pressure

◆ boiling_temperature_at_atmospheric_pressure

◆ evaporative_mass_flux

◆ helper_mass_flux

◆ helper_temperature_ratio

◆ latent_heat_of_evaporation

◆ specific_gas_constant

◆ specific_heat_ratio_vapor

◆ temperature_constant

◆ temperature_jump

EvaporationModelKnight< number, number_2 > Class Template Reference