Electrical Potential

ElectricalPotential manages the electrode configuration of an electrochemical simulation. It declares how many electrodes are present in the domain, pairs each with its counter-electrode, and reads the integer elementary-charge valence $z_q$ of every component. The module then computes each component's molar charge

$$\begin{array}{}\text{(1)}& {\mathtt{\text{MolarCharge}}}_q=z_{q}F,\end{array}$$

with $F$ the Faraday constant, which ElectricProperties uses to build the space charge density consumed by the Poisson solver described on the Electrics overview.

Key Classes and Concepts

• ElectricalPotential : public OPObject: holds the electrode list, the per-component ElementarCharges[q] and derived MolarCharge[q].
• Electrode: one electrode entry with an index, a charge, an interface volume, a 3-vector position, and a counter-electrode index.

Usage

Input

Defined in the @ElectricalPotential block. Electrodes are numbered 1-based in the input; inside the code they are stored zero-based (the reader subtracts 1).

@ElectricalPotential

$Nelectrodes    Number of electrodes in the domain       : 2

$CntElectr1     Counter-electrode index for electrode 1  : 2
$CntElectr2     Counter-electrode index for electrode 2  : 1

# Elementary charge valence of each component (zero-based) {#elementary-charge-valence-of-each-component-zero-based}
$Z0             Valence of component 0                   : 1
$Z1             Valence of component 1                   : -1

Token	Variable	Type	Required
$Nelectrodes	Nelectrodes	int	yes
$CntElectr<i>	electrodes[i-1].counterElectrode	int (1-based on input)	yes, one per electrode
$Z<q>	ElementarCharges[q]	int	yes, one per component

Output

No dedicated output file. The derived MolarCharge[q] array is forwarded to ElectricProperties::CalculateChargeDensity during the solve, whose result ends up in the VTK output written through the Electrics overview solver pipeline.

Example

#include "ElectricalPotential.h"
#include "Electrics/ElectricProperties.h"

ElectricalPotential  EPot(OPSettings, InputFile);
ElectricProperties   ElecP(OPSettings, InputFile);

for(RTC.tStep = RTC.tStart; RTC.tStep <= RTC.nSteps; RTC.IncrementTimeStep())
{
    // ElecP uses ElementarCharges published by EPot
    ElecP.CalculateChargeDensity(Cx);
    ElecP.SetBoundaryConditions(BC);
    // ... solver step ...
}

Dependencies

• Composition — component list.
• ElectricProperties — consumer of the per-component molar-charge array.
• Electrics (overview) — the spectral solver.
• PhysicalConstants::Faraday — the Faraday constant used in the ${\mathtt{\text{MolarCharge}}}_q=z_{q}F$ conversion.