Calculated properties for a single component phase field model using polynomial free energies. More...

#include <PFParamsPolyFreeEnergy.h>

Inheritance diagram for PFParamsPolyFreeEnergy:

Public Member Functions
	PFParamsPolyFreeEnergy (const InputParameters &parameters)

Protected Member Functions
virtual void	computeQpProperties ()

Protected Attributes
const VariableValue &	_c
	Variable values. More...

const VariableValue &	_T

MaterialProperty< Real > &	_M
	Mateiral property declarations. More...

MaterialProperty< RealGradient > &	_grad_M

MaterialProperty< Real > &	_kappa

MaterialProperty< Real > &	_c_eq

MaterialProperty< Real > &	_W

MaterialProperty< Real > &	_Qstar

MaterialProperty< Real > &	_D

Real	_int_width
	Input parameters. More...

Real	_length_scale

Real	_time_scale

MooseEnum	_order

Real	_D0

Real	_Em

Real	_Ef

Real	_surface_energy

const Real	_JtoeV

const Real	_kb

Detailed Description

Calculated properties for a single component phase field model using polynomial free energies.

Definition at line 23 of file PFParamsPolyFreeEnergy.h.

Constructor & Destructor Documentation

◆ PFParamsPolyFreeEnergy()

PFParamsPolyFreeEnergy::PFParamsPolyFreeEnergy ( const InputParameters & parameters )

Definition at line 38 of file PFParamsPolyFreeEnergy.C.

   : Material(parameters),
     _c(coupledValue("c")),
     _T(coupledValue("T")),
     _M(declareProperty<Real>("M")),
     _grad_M(declareProperty<RealGradient>("grad_M")),
     _kappa(declareProperty<Real>("kappa")),
     _c_eq(declareProperty<Real>("c_eq")),
     _W(declareProperty<Real>("barr_height")),
     _Qstar(declareProperty<Real>("Qstar")),
     _D(declareProperty<Real>("D")),
     _int_width(getParam<Real>("int_width")),
     _length_scale(getParam<Real>("length_scale")),
     _time_scale(getParam<Real>("time_scale")),
     _order(getParam<MooseEnum>("polynomial_order")),
     _D0(getParam<Real>("D0")),
     _Em(getParam<Real>("Em")),
     _Ef(getParam<Real>("Ef")),
     _surface_energy(getParam<Real>("surface_energy")),
     _JtoeV(6.24150974e18), // joule to eV conversion
     _kb(8.617343e-5)       // Boltzmann constant in eV/K
 {
 }

Member Function Documentation

◆ computeQpProperties()

void PFParamsPolyFreeEnergy::computeQpProperties ( )

protectedvirtual

Definition at line 63 of file PFParamsPolyFreeEnergy.C.

 {
   // Convert mobility from m^2/s to the length and time scale
   Real D0_c = _D0 * _time_scale / (_length_scale * _length_scale);
  
   Real kbT = _kb * _T[_qp];
  
   // Compute equilibrium concentration and diffusivity
   _c_eq[_qp] = std::exp(-_Ef / kbT);
   _D[_qp] = D0_c * std::exp(-_Em / kbT);
  
   // Compute free energy integral constant, such that int^1_0 f_loc = KN*sqrt(W)
   Real KN = 0.0;
  
   switch (_order)
   {
     case 0: // Fourth oder
       KN = 2.0 / 3.0;
       break;
     case 1: // Sixth order
       KN = 3.0 / 16.0 * std::sqrt(3.0) + 9.0 / 64.0 * std::sqrt(2.0) *
                                              (std::log(-std::sqrt(2.0) + std::sqrt(3.0)) +
                                               std::log(std::sqrt(2.0) + std::sqrt(3.0)));
       break;
     case 2: // Eigth order
       KN = 0.835510425;
       break;
     default:
       paramError("polynomial_order", "Incorrect polynomial order");
   }
  
   // Convert surface energy from J/m2 to eV/length_scale
   Real surf_energy = _surface_energy * _JtoeV * _length_scale * _length_scale;
  
   // Set interfacial parameter and energy barrier
   _kappa[_qp] = surf_energy * _int_width / KN;
   _W[_qp] = surf_energy / (2.0 * _int_width * KN);
  
   Real Co = 0.0;
   Real a = _c_eq[_qp];
  
   switch (_order)
   {
     case 0: // 4th order polynomial
       Co = std::pow(2.0, 5.0) * (1.0 + 2.0 * a - 2.0 * a * a);
       break;
     case 1: // 6th order polynomial
       Co = std::pow(2.0, 7.0) * (9.0 / 2.0 * a - 9.0 / 2.0 * a * a + 3.0 / 4.0);
       break;
     case 2: // 8th order polynomial
       Co = std::pow(2.0, 9.0) * (15.0 / 4.0 * a - 15.0 / 4.0 * a * a + 3.0 / 8.0);
       break;
     default:
       mooseError("Error in PFParamsPolyFreeEnergy: incorrect polynomial order");
   }
  
   _M[_qp] = KN / Co * (_D[_qp] * _int_width / surf_energy);
   _grad_M[_qp] = 0.0;
  
   _Qstar[_qp] = -4.0; // eV
 }