• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.72-82
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• 2017

Nozzleless booster is one of the applicable components for integral rocket ramjet (IRR). In order to predict nozzleless solid booster performance, the simplified theoretical analysis was applied for L/D=5, 6, 7, 9, 11, and 13. Al-HTPB and Zr-HTPB propellant with a high metal content were used to increase the hardness because of the combustion gas flow effect. It was found that the trends between the simplified theoretical analysis and experiments were similar.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.4
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• pp.52-62
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• 2017

The study for the performance characteristics of the nozzleless booster used in ramjet booster was carried out. Performances related to pressure and thrust for nozzleless booster are lower than classical motor those because of absence of convergent and divergent sections of nozzle. To solve this problem, it developed a high-performance propellant with maximum impulse density included Al as metal fuel. Using the nozzleless booster casted the propellant, ground test of it was carried out by varying the length-to-diameter ratio (L/D ratio) of the propellant. Specific impulse of nozzleless booster was limited to about 75 percents of its value compared with that of classical motor adapted nozzle in the same propellant and propellant length and will be estimated approximately 85 percents of its value compared with that of classical motor at same average pressure in terms of the curve fitting by our test results.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.18-25
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• 2017

The study for the combustion characteristics of propellants for nozzleless boosters was carried out. The metal fuels of Al and Zr were introduced into solid propellant formulations in order to enhance the density-specific impulse and the high burning rate with low pressure exponent was investigated as the major combustion characteristic of propellant to design nozzleless boosters. The burning rate of Zr-containing propellant was higher than Al-containing propellant and, $13{\mu}m$ Zr-containing propellant exhibited the burning rate of 35 mm/s (at 1000 psi)and pressure exponent of 0.3282. The benefit of using Al and Zr-containing propellant into nozzleless boosters was demonstrated in these results.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.38-51
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• 2018

This study was carried out to improve the performance characteristics of nozzleless boosters that are used in ramjet boosters. A propellant using Zr as the metal fuel was developed, which provided a higher density than the propellant using Al as the metal fuel. The developed propellant was cast using the nozzleless booster and a ground test was carried out by varying the length-to-diameter ratio (L/D ratio) of the propellant. From a comparison between the performance characteristics of propellants using Zr and Al, it was proved that the performance of the propellant using Zr is higher than that of propellant using Al, except for the specific impulse, under all tested conditions. As the length-to-diameter ratio was increased, the specific impulse of the propellant using Zr was decreased by 88% compared with that of the propellant with Al. However, because of the density difference between the propellants, the impulse density of the propellant with Zr was higher than that of the propellant with Al under all tested conditions.