diff options
| -rw-r--r-- | wi.c | 67 |
1 files changed, 65 insertions, 2 deletions
@@ -2,6 +2,7 @@ #include <math.h> #include <gsl/gsl_vector.h> #include <gsl/gsl_multiroots.h> +#include <gsl/gsl_interp2d.h> #define CP_DFM CP_AIR /* specific heat of dry mixture at constant pressure at 273K [kJ/(kg*K)] --- CP_DFM=CP_AIR assumes no fuel */ @@ -63,6 +64,19 @@ const unsigned int ve_tbl[N_P_BRPOINTS][N_RPM_BRPOINTS] = { {75, 80, 85, 90, 95, 95, 93, 90} /* - rpm + */ }; +const double w_eq_ratio[N_P_BRPOINTS][N_RPM_BRPOINTS] = { + {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}, + {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}, + {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}, + {0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}, + {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0} +}; /* function definitions */ @@ -125,8 +139,57 @@ m_rate_air(double p, double t, unsigned int s) { /* volumetric efficiency at air pressure p [Pa] and engine speed s [rpm] */ double ve(double p, unsigned int s) { - /* TODO */ - return 1.0; + size_t i, j; + double *xa, *ya, *za; + + /* allocate axes */ + if (!(xa = calloc(N_RPM_BRPOINTS, sizeof(double)))) { + fprintf(stderr, "failed to allocate x-axis\n"); + return 0.0; + } + if (!(ya = calloc(N_P_BRPOINTS, sizeof(double)))) { + fprintf(stderr, "failed to allocate y-axis\n"); + free(xa); + return 0.0; + } + if (!(za = calloc(N_RPM_BRPOINTS*N_P_BRPOINTS, sizeof(double)))) { + fprintf(stderr, "failed to allocate z values\n"); + free(xa); + free(ya); + return 0.0; + } + /* copy axis values */ + for (i = 0; i < N_RPM_BRPOINTS; i++) { + xa[i] = (double) rpm_brpoints[i]; + } + for (i = 0; i < N_P_BRPOINTS; i++) { + ya[i] = p_brpoints[i]; + } + + /* initialize interpolator */ + const gsl_interp2d_type *interpt = gsl_interp2d_bilinear; + gsl_interp2d *interp = gsl_interp2d_alloc(interpt, N_RPM_BRPOINTS, N_P_BRPOINTS); + (void) gsl_interp2d_init(interp, xa, ya, za, N_RPM_BRPOINTS, N_P_BRPOINTS); + gsl_interp_accel *xacc = gsl_interp_accel_alloc(); + gsl_interp_accel *yacc = gsl_interp_accel_alloc(); + /* copy ve table to za */ + for (j = 0; j < N_P_BRPOINTS; j++) { + for (i = 0; i < N_RPM_BRPOINTS; i++) { + (void) gsl_interp2d_set(interp, za, i, j, ve_tbl[j][i]/100.0); + } + } + + /* interpolate table */ + double res = gsl_interp2d_eval_extrap(interp, xa, ya, za, s, p, xacc, yacc); + + gsl_interp2d_free(interp); + gsl_interp_accel_free(xacc); + gsl_interp_accel_free(yacc); + free(xa); + free(ya); + free(za); + + return res; } /* specific enthalpy of mixture h [kJ/kg] at temperature t [K] and specific water content w */ |