• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.113-116
• /
• 2008

Pseudo-3D Spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio $(L/d_o)$ of 1.67 and at the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.05a
• /
• pp.145-148
• /
• 2008

A 50 Newton monopropellant thruster being developed for attitude control in a variety of aerospace application systems is described in this paper. A scaled down thruster with platinum on aluminum oxide in the reaction chamber was tested to determine the catalyst capacity. A scaled up thruster, was designed and fabricated using data obtained on small scale device, was evaluated by decomposition efficiency based on temperature, efficiency of characteristic velocity, and measurement of thrust. The performance of a scaled up thruster was 42 Newton in thrust, 98 % in efficiency of characteristic velocity, and 123 sec in specific impulse at sea level.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.3
• /
• pp.24-33
• /
• 2008

A 50 Newton monopropellant thruster being developed for attitude control in a variety of aerospace application systems is described in this paper. A scaled down thruster with platinum on aluminum oxide in the reaction chamber was tested to determine the catalyst capacity. A scaled up thruster which was designed and fabricated using data obtained from a small scale device was evaluated by its decomposition efficiency based on the temperature, the efficiency of characteristic velocity, and the measurement of thrust. The performance of a scaled up thruster was marked by a measured thrust of 42 Newton, 98 % efficiency of the characteristic velocity, a specific impulse of 123 sec at sea level.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.10a
• /
• pp.35-38
• /
• 2003

The purpose of this work is to introduce the 1-N grade thruster development program for attitude control of satellites and lunch vehicle systems. Characteristics of the thruster and its performance have been evaluated through hot-firing test of small liquid engine inside a vacuum test cell. Performance evaluation of thruster were made with a variation of propellant injection pressure at steady state and pulse firing mode, respectively. Also hot-fire test system and test procedure are briefly described, too.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.406-408
• /
• 2017

Ammonium dinitramide (ADN) Low toxicity monopropellant based 1N class thruster and test equipment were developed. Compared with the hydrazine which used in existing satellite thruster, ADN is easy to handle and has excellent physical characteristics such as density and specific impulse. Due to these characteristics, ADN is attracting attention as an eco-friendly propellant. In this paper, 1N class thruster and thrust measurement system was designed for performance testing of ADN monopropellant. The composition of the propellant for the design and experiment was set at 11.2: 25.4: 63.4 for each of Methanol: $H_2O$: ADN.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.288-293
• /
• 2001

This paper presents the water-hammer effect due to the rapid opening and closing of isolation valve and thruster valve in the spacecraft propulsion system. The single propellant feed system was modeled to investigate the maximum peak pressure due to the water-hammer effect. The test parameters are tank supply pressure, shape and throat length of orifice and line length. Kerosene was used as the inert simulant propellant liquid instead of hydrazine. As downstream line length after isolation valve increased from 1.5 to 2.5m, the maximum line-filling water-hammer peak pressure decreased, but the average time interval between peak pressures increased. The maximum line-filling water-hammer peak pressure with orifice was lower than without orifice, and the maximum line-filling water-hammer peak pressure with orifice at the back of isolation valve was lower than with orifice in front of isolation valve. Without orifice, the maximum water-hammer peak pressure due to the rapid opening and closing of the thruster valve was about 126% of tank supply pressure. With orifice, it decreased. As orifice throat length increased, it decreased. The maximum water-hammer peak pressure due to the rapid closing of the thruster valve with converging-diverging orifice was lower than normal orifice. It was found that the orifice as a means of pressure drop was very effective to reduce the water hammer peak pressure at the thruster valve. The results of this study can be used for the design of spacecraft liquid propulsion feed system.

• Journal of Aerospace System Engineering
• /
• v.6 no.4
• /
• pp.24-28
• /
• 2012

In this paper, 2-D experiment and steady-state computational fluid analysis were conducted for measuring the hear transfer coefficient of pintle type controllable thruster in high pressure and temperature. In case of 2-D experiment, transient liquid crystal technique was used for measuring heat transfer coefficient for the 2-D pintle model. The experimental result was used to validate the CFD result. The CFD results well predicted the heat transfer coefficient on the pintle surface except the nozzle downstream region, where the results by CFD was higher than experimental results. The CFD results were also compared with the result by Bartz equation and the it was shown that the Bartz equation overestimated the heat transfer coefficient on the nozzle throat as much as 80%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.275-278
• /
• 2010

By changing the nozzle throat area during the operation, thrust of a pintle thruster can be adjusted easily such as a liquid propulsion. In this paper, numerical analysis was carried out for SNECMA's pintle thruster with different pintle shapes. Flow field and aerodynamic load changed drastically with pintle shapes. Bore in the pintle decreased aerodynamic load significantly.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.739-745
• /
• 2017

Research of ADN-based monopropellant thruster is progressed by developed countries in Europe to replace toxic hydrazine, and ADN-based monopropellant thruster system is the only system that was proved in space environment. In this research, ADN-based propellant and catalyst was fabricated to develop ADN-based monopropellant thruster, and catalytic combustion performance with fabricated propellant and catalyst were evaluated with DSC-TG analysis. Catalytic combustion of propellant and catalyst was determined with firing test using 5 N scale liquid monopropellant thruster.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.17 no.1
• /
• pp.1-8
• /
• 2013

A liquid-monopropellant hydrazine thruster has several outstanding advantages such as relatively-simple structure, long/stable propellant storability, clean exhaust products, and so on. Therefore hydrazine thruster has such a wide application as orbit and attitude control system (ACS) for space vehicles. A hydrazine thruster with the medium-level thrust to be used in the ACS of space launch vehicles (SLV) has been developed, and its ground firing test result is presented in terms of thrust, impulse bit, temperature, and chamber pressure. It is verified through the performance test that the response and repeatability of thrust are very excellent, and the thrust efficiencies compared to its ideal requirement are larger than 93%.