*4.2.2 The complete test setup*

The **Figure 9** shows the complete test setup including nitrous boost stage, main ignition stage and purge lines. Nitrous boost stage uses the Aluminum 6061 based oxidizer tank with maximum operating pressure of 280 bars. Nitrous oxide is stored around 50 bars. Nitrous line consist of Mv (manual) and Av (automatic) valves for the operation. Purge line uses the same tank as Nitrous line. Purge tank stores 30

**Figure 8.** *Actual experiment images.*

**Figure 9.** *The complete test setup.*

bars nitrogen to cool down the motor after the ignition. Main oxidizer tank is a 10-liter aluminum tank, includes *CO*2*=N*2*O* mixture in "blowdown" mode. Main tank has relief with 90 bars cracking pressure. Tank also has vent valves. In addition, mechanical pressure gauge shows the oxidizer pressure as a backup of the National Instruments DAQ system [19].

Check valves are used in all feed lines as well as just before the motor entrance. Check valve prevents hydrocarbon fuel leakage through to nitrous lines. If the nitrous vapor phase interacts with the hydrocarbon, it suddenly decomposes into nitrogen and oxygen (releases þ19*:*5 kcal*=*mole energy). Karabeyoglu [9] experienced decomposition hazard of nitrous due to deflagration wave as sudden pressure increase from 52 bars to 900 bars in 3 seconds. A K-type thermocouple is used to measure the temperatures. Pressure transducer has measuring efficiency � 0.5% of the full measurement scale of 70 bars with repeatability that is better than � 0.05%. Pressure/temperature are recorded by using a National Instruments Data Acquisition System and Lab View signal express software. The sampling rate of the DAQ system was set to 5120 Hz. Detail sensitivity features in error analysis is explained in appendix section of this thesis.
