add compressor outlet temperature output

1 files changed, 22 insertions, 1 deletions

diff --git a/engine.c b/engine.c
index 5c1568d..b4db059 100644
--- a/engine.c
+++ b/engine.c
@@ -1,3 +1,4 @@
+#include <math.h>
 #include <string.h>
 
 #include "unit.h"
@@ -5,7 +6,16 @@
 
 
 /* A four-stroke piston engine takes two revolutions per cycle. */
-#define REV_PER_CYCLE 2.0
+static const double REV_PER_CYCLE = 2.0;
+
+/* Specific heat of dry air at constant pressure at T=300K [J/(kg*K)]. */
+static const double C_P_AIR = 1005.0;
+
+/* Specific heat of dry air at constant volume at T=300K [J/(kg*K)]. */
+static const double C_V_AIR = 718.0;
+
+/* Heat capacity ratio of dry air at T=300K [J/(kg*K)]. */
+static const double GAMMA_AIR = C_P_AIR / C_V_AIR;
 
 
 void
@@ -28,6 +38,17 @@ comp_outlet_pressure(const Engine *e) {
 	return e->map + e->intercooler_deltap;
 }
 
+Temperature
+comp_outlet_temperature(const Engine *e) {
+	Temperature t1;
+	Pressure p1, p2;
+
+	t1 = e->ambient_temperature;
+	p1 = e->ambient_pressure;
+	p2 = comp_outlet_pressure(e);
+	return t1 * pow(p2/p1, (GAMMA_AIR-1.0)/GAMMA_AIR);
+}
+
 VolumeFlowRate
 volume_flow_rate(const Engine *e) {
 	double n = as_rpm(e->rpm);