Learning Forum

[Zwernjayden]

Its steady state. Would it be like this? Im a bit confused how the arguments for the F_PROFILE work. What does the i and the i+1 do? It says its supposed to determine which profile is which but I don't see a way to actually select it in the GUI.

#include "udf.h"

#include

 

DEFINE_PROFILE(combined_surface_and_mass_flow_profile, t, i)

{

    face_t f;

    real Ts, heat_flux, Hv, r, Ts_old, Ts_new, m_dot, error;

    int iter;

   

 

    begin_f_loop(f, t)

    {

        if (THREAD_ID(t) == 6)  // Select fuel grain surface

        {

            // Initial values and heat flux retrieval

            Ts = F_T(f, t);

            heat_flux = BOUNDARY_HEAT_FLUX(f, t);

 

            // Iterative calculation for new surface temperature

            Ts_old = Ts;

            iter = 0;

            error = 1;

            while (error > 1e-6 && iter < 10)

            {

                Hv = 2033631 + 310000 + 1500 * (Ts_old - 298);  // Update Hv formula as needed

                r = heat_flux / (Hv * 754);  // Regression rate calculation

                Ts_new = 20557.188 / (8.314 * (log(0.01104) - log(r)));  // New surface temperature calculation

                error = fabs(Ts_new - Ts_old);  // Compute error

                Ts_old = Ts_new;  // Prepare for next iteration

                iter++;

            }

            // Update the surface temperature profile at the face

            F_PROFILE(f, t, i) = (Ts + 0.1 * (Ts_new - Ts));

    r = heat_flux / (Hv * 754);

            // Compute mass flow rate based on the final regression rate

            m_dot = 754 * r;  // Use the same r calculated for temperature

            F_PROFILE(f, t, i+1) = m_dot;  // Assuming 'position + 1' is the correct slot for mass flow rate

        }

    }

    end_f_loop(f, t)

}