repeatable. Experiments were carried out using the experi- mental facility shown in Fig. 2. The hybrid rocket motor used for the experiments is shown in Fig. 3. The pressure transducer (P3) was fixed to the hybrid rocket motor upstream of the nozzle end at a distance of around 30 mm. The sampling rate of the pressure transducer was 2 kHz. The transducer was protected from hot com- bustion products, by connecting it to the motor through a stainless steel tube (2 mm inner diameter and 150 mm length), where the intermediate medium between trans- ducer and hot combustion products was silicon oil. The settling chamber temperature (T1) and pressure (P2) were also recorded. The experiments were conducted for a burn time of 4 s. The pressure time data obtained for four different experiments are shown in Fig. 4. The pressure
data obtained was filtered through a low bandwidth filter to remove the noise due to the electrical signal.
It is observed from Fig. 4 that the combustion chamber pressure as well as the settling chamber pressure is repeatable. The temperature measured with the help of T-type thermocouple is shown in Fig. 5.
It is seen that the decrease in settling chamber tem- perature is negligible, hence an averaged temperature (307 K) was used in Eq. (2) for calculating the oxidizer mass flow rate. The total mass of fuel burnt and the total mass of oxidizer consumed in 4 s were also recorded and