Based on the original Rocket Workbench on SourceForge in CVS at:
https://sourceforge.net/projects/rocketworkbench
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156 lines
6.0 KiB
156 lines
6.0 KiB
/* Liquid rocket design */
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include "libcpropep/include/print.h"
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#include "libcpropep/include/type.h"
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#include "libthermo/include/thermo.h"
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#include "libcpropep/include/conversion.h"
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#include "liblrd/include/lrd.h"
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#ifndef M_PI
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#define M_PI 3.14159265358979323846
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#endif
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int LRD_compute_caracteristics(equilibrium_t *e, design_param_t *d, motor_t *m,
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liquid_propellant_t *p)
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{
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equilibrium_t *throat, *exit;
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throat = e + 1;
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exit = e + 2;
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m->mass_flow_rate = d->thrust / exit->performance.Isp;
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m->fu_flow_rate = m->mass_flow_rate / (p->o_f_ratio + 1);
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m->ox_flow_rate = m->mass_flow_rate - m->fu_flow_rate;
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m->throat_area = m->mass_flow_rate * throat->performance.a_dotm
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/ ATM_TO_PA;
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m->throat_diameter = 2 * sqrt(m->throat_area / M_PI);
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m->throat_radius = m->throat_diameter/2;
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m->exit_area = m->throat_area * exit->performance.ae_at;
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m->exit_diameter = 2 * sqrt(m->exit_area / M_PI);
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m->exit_radius = m->exit_diameter/2;
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m->Ac_At = pow(d->Dc_Dt, 2);
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m->chamber_volume = d->Lstar * m->throat_area;
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m->chamber_diameter = d->Dc_Dt * m->throat_diameter;
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m->chamber_radius = m->chamber_diameter/2;
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m->chamber_area = M_PI * pow(m->chamber_radius, 2);
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m->convergent_length = (m->throat_radius*(sqrt(m->Ac_At) - 1) +
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d->R_Rt*m->throat_radius*
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(pow(cos(d->theta*M_PI/180),-1) -1))
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/tan(d->theta*M_PI/180);
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/* m->convergent_volume = (M_PI/3)*m->convergent_length*
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(pow(m->chamber_radius, 2)+pow(m->throat_radius, 2)+
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m->chamber_radius*m->throat_radius); */
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m->convergent_volume = (1/3) * m->throat_area *sqrt(m->throat_area/M_PI) *
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pow(tan(d->theta*M_PI/180), -1)*(pow(m->Ac_At, 1/3) - 1);
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/*
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m->convergent_length = d->R_Rt*m->throat_radius*sin(d->theta*M_PI/180) +
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(m->chamber_radius - d->R_Rt*m->throat_radius*(cos(d->theta*M_PI/180)-1)
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- m->throat_radius)/tan(d->theta*M_PI/180);
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*/
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m->cylinder_volume = m->chamber_volume - m->convergent_volume;
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m->cylinder_length = m->cylinder_volume / m->chamber_area;
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m->chamber_length = m->cylinder_length + m->convergent_length;
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m->walls_area = 2*m->chamber_length*sqrt(M_PI*m->Ac_At*m->throat_area)
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+ pow(sin(d->theta), -1)*(m->Ac_At - 1)*m->throat_area;
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return 0;
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}
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int LRD_print_propellant_info(liquid_propellant_t *p)
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{
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printf("Propellant\n");
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printf("----------\n");
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printf("Fuel : %s\n", PROPELLANT_NAME(p->fuel));
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printf("Oxidant : %s\n", PROPELLANT_NAME(p->oxidant));
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printf("O/F ratio : %.2f\n\n", p->o_f_ratio);
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return 0;
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}
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int LRD_print_design_criteria(design_param_t *c)
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{
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printf("Design criteria\n");
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printf("---------------\n");
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printf("Chamber pressure (atm) (psi) : % 11.4f % 11.4f\n",
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c->chamber_pressure, c->chamber_pressure * ATM_TO_PSI);
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printf("Thrust (N) (lbf) : % 11.4e % 11.4e\n",
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c->thrust, c->thrust * N_TO_LBF);
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printf("L* (m) (in) : % 11.4f % 11.4f\n",
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c->Lstar, c->Lstar * M_TO_IN);
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printf("Chamber to throat diameter : % 11.4f\n",
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c->Dc_Dt);
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printf("R/Rt : % 11.4f\n",
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c->R_Rt);
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printf("Convergent half angle (deg) : % 11.4f\n", c->theta);
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printf("\n");
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return 0;
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}
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int LRD_print_design_information(motor_t *mf, motor_t *ms)
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{
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printf("\n");
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printf(" "
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"frozen | shifting\n");
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printf("Mass flow rate (kg/s) (lb/s) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->mass_flow_rate, mf->mass_flow_rate * KG_S_TO_LB_S,
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ms->mass_flow_rate, ms->mass_flow_rate * KG_S_TO_LB_S);
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printf("Fuel flow rate (kg/s) (lb/s) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->fu_flow_rate, mf->fu_flow_rate * KG_S_TO_LB_S,
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ms->fu_flow_rate, ms->fu_flow_rate * KG_S_TO_LB_S);
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printf("Oxidant flow rate (kg/s) (lb/s) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->ox_flow_rate, mf->ox_flow_rate * KG_S_TO_LB_S,
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ms->ox_flow_rate, ms->ox_flow_rate * KG_S_TO_LB_S);
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printf("Throat area (m^2) (in^2) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->throat_area, mf->throat_area * M2_TO_IN2,
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ms->throat_area, ms->throat_area * M2_TO_IN2);
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printf("Throat diameter (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->throat_diameter, mf->throat_diameter * M_TO_IN,
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ms->throat_diameter, ms->throat_diameter * M_TO_IN);
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printf("Exit area (m^2) (in^2) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->exit_area, mf->exit_area * M2_TO_IN2,
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ms->exit_area, ms->exit_area * M2_TO_IN2);
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printf("Exit diameter (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->exit_diameter, mf->exit_diameter * M_TO_IN,
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ms->exit_diameter, ms->exit_diameter * M_TO_IN);
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printf("Chamber volume (m^3) (in^3) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->chamber_volume, mf->chamber_volume * M3_TO_IN3,
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ms->chamber_volume, ms->chamber_volume * M3_TO_IN3);
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printf("Chamber diameter (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->chamber_diameter, mf->chamber_diameter * M_TO_IN,
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ms->chamber_diameter, ms->chamber_diameter * M_TO_IN);
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printf("Chamber length (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->chamber_length, mf->chamber_length * M_TO_IN,
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ms->chamber_length, ms->chamber_length * M_TO_IN);
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printf("Convergent length (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->convergent_length, mf->convergent_length * M_TO_IN,
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ms->convergent_length, ms->convergent_length * M_TO_IN);
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printf("Cylinder length (m) (in) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->cylinder_length, mf->cylinder_length * M_TO_IN,
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ms->cylinder_length, ms->cylinder_length * M_TO_IN);
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printf("Chamber walls area (m^2) (in^2) : %8.4e %8.4e | %8.4e %8.4e\n",
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mf->walls_area, mf->walls_area * M2_TO_IN2,
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ms->walls_area, ms->walls_area * M2_TO_IN2);
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return 0;
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}
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