ThermalResistancesCoaxial.h

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <cmath>
#include <numbers>
 
#include "GroutParameters.h"
#include "Pipe.h"
#include "RefrigerantProperties.h"
#include "ThermalResistanceHelpers.h"
 
namespace ProcessLib
{
namespace HeatTransportBHE
{
namespace BHE
{
struct AdvectiveThermalResistanceCoaxial
{
    double const inner_pipe_coaxial;
    double const a_annulus;
    double const b_annulus;
};
 
struct PipeWallThermalResistanceCoaxial
{
    double const inner_pipe_coaxial;
    double const annulus;
};
 
struct GroutAndGroutSoilExchangeThermalResistanceCoaxial
{
    double const conductive_b;
    double const grout_soil;
};
 
inline AdvectiveThermalResistanceCoaxial calculateAdvectiveThermalResistance(
    Pipe const& inner_pipe, Pipe const& outer_pipe,
    RefrigerantProperties const& fluid, double const Nu_inner_pipe,
    double const Nu_annulus)
{
    double const hydraulic_diameter =
        coaxialPipesAnnulusDiameter(inner_pipe, outer_pipe);
 
    auto advective_thermal_resistance = [&](double Nu, double diameter_ratio)
    {
        return 1.0 / (Nu * fluid.thermal_conductivity * std::numbers::pi) *
               diameter_ratio;
    };
    return {advective_thermal_resistance(Nu_inner_pipe, 1.),
            advective_thermal_resistance(
                Nu_annulus, hydraulic_diameter / inner_pipe.outsideDiameter()),
            advective_thermal_resistance(
                Nu_annulus, hydraulic_diameter / outer_pipe.diameter)};
}

inline PipeWallThermalResistanceCoaxial calculatePipeWallThermalResistance(
    Pipe const& inner_pipe, double const lambda_p_inner, Pipe const& outer_pipe,
    double const lambda_p_outer)
{
    return {pipeWallThermalResistance(inner_pipe, lambda_p_inner),
            pipeWallThermalResistance(outer_pipe, lambda_p_outer)};
}
 
inline GroutAndGroutSoilExchangeThermalResistanceCoaxial
calculateGroutAndGroutSoilExchangeThermalResistance(
    Pipe const& outer_pipe, GroutParameters const& grout_parameters,
    double const borehole_diameter)
{
    double const outer_pipe_outside_diameter = outer_pipe.outsideDiameter();
    double const chi =
        std::log(std::sqrt(borehole_diameter * borehole_diameter +
                           outer_pipe_outside_diameter *
                               outer_pipe_outside_diameter) /
                 std::sqrt(2) / outer_pipe_outside_diameter) /
        std::log(borehole_diameter / outer_pipe_outside_diameter);
    double const R_g =
        std::log(borehole_diameter / outer_pipe_outside_diameter) / 2 /
        (std::numbers::pi * grout_parameters.lambda_g);
    double const conductive_b = chi * R_g;
    double const grout_soil = (1 - chi) * R_g;
    return {conductive_b, grout_soil};
}
}  // namespace BHE
}  // namespace HeatTransportBHE
}  // namespace ProcessLib