• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.5
• /
• pp.91-96
• /
• 2004

An optimal design of the gas generator for Liquid Rocket Engine (LRE) was conducted. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton in thrust with RP-1/LOx propellant. The optimal design was done for maximizing specific impulse of thrust chamber with constraints of combustion temperature and for matching the power requirement of turbopump system. Design variables are total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design provide length, diameter, and contraction ratio of gas generator. And the operational condition predicted by design code with resulting configuration was found to maximize the objective function and to meet the design constraints. The results of optimal design will be tested and verified with combustion experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.10
• /
• pp.1027-1037
• /
• 2009

The development of a combustion chamber for a 30-$ton_f$ regeneratively-cooled space liquid rocket engine is described. Starting from the development of bi-propellant swirl coaxial injectors, essential technologies were verified through subscale combustion chambers and afterwards applied to the full-scale combustion chambers. A total of 5 full-scale combustion chambers have been utilized to verify ignition, combustion efficiency and stability, cooling, and duration requirements. A total of 46 combustion tests were performed among which 23 tests were parallely performed with stability rating tests using a pulse gun device. The test results have revealed that the 30-$ton_f$ regeneratively-cooled combustion chamber fully complies to the performance and combustion stability requirements and thus concluded that the development is successfully completed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.6
• /
• pp.78-84
• /
• 2020

The performance of pintle thruster is analyzed by using the pintle thruster performance analysis model which integrating the element models introduced in Part I. To verify the performance analysis, the results of the developed program are compared with the experimental data of kerosene/hydrogen peroxide liquid pintle thrusters. Based on the results, the characteristics of the pintle thruster are analyzed. The sensitivity analysis is performed to investigate the effect of thruster shape and operation parameters on performance characteristics using both OAT and scatter plot methods. The four performance parameters such as droplet diameter, film flow rate, O/F ratio, and nozzle throat diameter are evaluated to investigate their effects on characteristic speed, combustor pressure, and specific thrust.

• The Korean Journal of Mycology
• /
• v.31 no.1
• /
• pp.22-27
• /
• 2003

This research aimed at developing the efficient method and device applicable to the inoculation of mushroom using (spawn was intended to utilize) liquid spawn for the stable production of mushroom. For the mass production of liquid culture, optimal inoculum volume and cultural period were $5{\sim}6%$ and 4 days for Flammulina velutipes and 4% and 5 days for Pleurotus ostreatus. Fruit body weight in 850 ml polythene bottle was highest at 6% or 15 ml liquid inoculum for P. ostreatus and $4{\sim}6%$ or $10{\sim}15ml$ for F. velutipes. Weight of fruit body by the application of liquid spawn inoculation system increased up to 33.7% for P. ostreatus and 32.8% for F. velutipes, respetively, compared to conventional spawn making system. The system of liquid spawn inoculation was successfully operated without malfunction in opening or closing the lid, and it took 26 min to inoculate 1200 bottles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2000.04a
• /
• pp.7-7
• /
• 2000

액체추진 로켓 분야에서 비연소 혼합시험(cold flow mixing test)은 로켓엔진의 성능을 예측하고 인젝터와 관련된 문제의 진단에 도움을 줄 수 있는 자료를 확보할 수 있는 수단이 된다. 비연소 혼합시험이 실제 연소시험을 대신할 수 있는 신뢰성 있는 자료를 제공할 수는 없지만, 인젝터의 최적형상을 설계하기 위해서 실시해야할 고 비용의 연소시험에 대한 횟수를 줄일 수 있는 보조시험으로서의 역할을 할 수 있다. 혼합시험 성능이 우수한 인젝터가 수력학적인 혼합성능을 능가하는 연소반응에 의해서 실제 연소시험에서는 성능이 저하되는 경우도 있을 수 있으나 대부분의 경우에는 비연소 혼합시험에서 좋은 성능을 나타내는 인젝터는 실제 연소시험에서도 좋은 성능을 나타낸다. 일반적으로 비연소시험과 연소시험 사이의 상관 관계를 정확히 정립하기 위해서는 많은 상관 관계 변수의 적용 및 충분한 혼합시험 자료가 요구된다.

• 한국전산유체공학회:학술대회논문집
• /
• 2009.04a
• /
• pp.130-134
• /
• 2009

CFD analysis of the fuel injection pattern and the flow field surrounding the liquid propellant injector of a small thruster is performed. A good agreement is shown with PIV test data for the initial configuration. Analysis on various injector shapes is performed to observe the effect of injector shape on the trajectories of liquid droplet. A various shapes of injector is investigated to enhance spray pattern of the small injector.

• Journal of the Korean Chemical Society
• /
• v.44 no.4
• /
• pp.316-321
• /
• 2000

We have constructed and tested a new reflectance spectrometer. Both the radiation source and the detector are embedded on the same side of the cell compartment..Its performance has been compared with that of the conventional absorption spectrometer ('Spectronic 20') using standard solutions of $Cu^{2+}$. The sen-sitivity of the reflectance spectrometer was found to be much higher than that of'Spectrortic 20' over the ana-lytical concentration range of l.00 ${\times}$$10^{-4}$M and 1.00 ${\times}$$10^{-1}$M of $Cu^{2+}$.

• Journal of ILASS-Korea
• /
• v.10 no.1
• /
• pp.35-42
• /
• 2005

The present study has numerically and experimentally investigated the spray behavior of liquid jet injected in subsonic cross-flow. The corresponding spray characteristics are correlated with jet operating parameters. The spray dynamics are known to be distinctly different in the three regimes: the column, the ligament and the droplet regimes. The behaviors of column, penetration and breakup of liquid jet have been studied. Numerical and physical models are base on a modified KIVA code. The primary atomization is represented by a wave model base on the KH(Kelvin-Helmholtz) instability that is generated by a high interface relative velocity between the liquid and gas flows. In odor to capture the spray trajectory, CCD camera has been utilized. Numerical and experimental results indicate that the breakup point is delayed by increasing gas momentum ratio and the penetration decreases by increasing Weber number.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.4
• /
• pp.132-144
• /
• 2003

Numerical analysis of the spray angles of Dual swirl injector were investigated to obtain basic design data and to predict the combustion performance. Using the commercial thermal hydraulic program, discharge coefficients and spray angles were numerically analyzed with recess length, pressure drop, velocity ratio, mixture ratio and back hole length. Water was used as simulants for oxidizer and fuel, respectively to compare the experimental results. Swirl injectors were designed to inject oxidizer of 70.5g/s and fuel of 29.5g/s at the pressure drop of 1MPa and two recess lengths were considered. In addition, the effect of injector geometry coefficient and velocity ratio on the discharge coefficient was studied.

• 한국연소학회:학술대회논문집
• /
• 1999.10a
• /
• pp.21-26
• /
• 1999

Liquefied petroleum gas(LPG) has been used as motor fuel due to its low emissions and low cost. The fuel feeding system has been improved with stringent requirement for exhaust emissions. LPG carburation system was firstly introduced, then the system changed into a gas injection system controlled precisely, but those gas feeding system has a limitation on improving power output. In order to improve an engine performance, a multi-point port injection system was introduced recently, and a liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray from diesel injectors. The spray images are visualized and compared with diesel sprays in a wide injection pressure range. The photographs show much wider dispersion of LPG sprays.