Theoretical Evaluation and Experimental Validation of Performance Parameters of New Hypergolic Liquid Fuel Blends with Red Fuming Nitric Acid as Oxidizer

A number of fuel blends based on 3-carene, norbornadiene, furfuryl alcohol, ethylidene norbornene, and kerosene in different weight proportions have been developed as rocket fuels which exhibit synergistic hypergolic ignition with red fuming nitric acid (RFNA) as oxidizer with low ignition delays (IDs < 40 ms). The optimum compositions of fuel blends were determined by measuring ID values of different blends at optimum O/F ratios. Eight selected fuel blends and one neat fuel (ethylidene norbornene) were theoretically evaluated for their performance parameters using NASA-CEC-7.1. software with RFNA as oxidizer at different O/F ratios and at chamber pressure of P-c, 2451.66 and 4903.33 (or 5197.52) kPa, keeping the exit pressure constant at 98.07 kPa. For experimental validation of performance parameters, static firing trials of these fuel blends with RFNA were carried out using 735.5 N thruster at 2451.66 kPa chamber pressure using doublet or triplet impinging stream type of injector. The experimental C* values were compared with theoretically determined C* values to predict combustion efficiencies which were found to be more than 95% in all the cases.