• Journal of Korea Society of Industrial Information Systems
• /
• v.18 no.5
• /
• pp.81-92
• /
• 2013

The satellite includes many release mechanisms such as solar array deployment, antenna deployment, cover to protect contamination in scientific equipment, pyro value of the propulsion subsytem, and bypass device in Li-Ion cell module. A drive the initiators is a critical to the successful mission because the initiators of release mechanism driving by the pyrotechnic circuit is operated in single short. The pyrotechnic circuit has to provide switching network for safety. A typical switching network has defect consisting of high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit is required some form of power conditioning to reduce the peak power demanded from the bus if the initiators are to be fired from the main bus. This paper design a pyrotechnic circuit synchronized to the fire-command to activate the fire switch to overcome use high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit provides a current limited widow pulse for fire current synchronized to the fire-command to insure that fire switch will only carry the current but never switch it. The current limited widow pulse for fire current can be possible to use low current rating and light mass switch in switching network. The current limit function in the pyrotechnic circuit reduces supply voltage to initiator and provides the effect of power conditioning function to reduce peak bus power. The pyrotechnic circuit to apply satellite development on geostationary orbit is verified the function by test in development model.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.17 no.4
• /
• pp.404-412
• /
• 2014

We proposed a design method for squib current supply & interlock circuits in guided-missile fire control systems. In order to design squib current supply circuits, various missile squib loads including line resistance and squib devices have to be considered in advance minimizing probability of redesign of circuits and reducing the development cost by implementing the most proper squib current supply circuit. Also, we presented a hardware interlock logic instead of the commonly used software safety logic to improve the safety of guided-missile fire control systems. The proposed squib interlock circuit enhances safety requirements of guided-missile fire control systems. We confirmed that simulation and measurement results of the proposed design method are the same as theoretical analysis results.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.6
• /
• pp.11-18
• /
• 2018

A pulse detonation engine (PDE) requires high operating frequency greater than 100 Hz to get meaning thrust as a propulsion devise. Thus a PDE needs an ignition circuit operating precisely at high operating frequencies. In this paper AC(alternating current) and DC(direct current) types of ignition circuits were designed and compared. Each circuit was tested at operating frequencies from 16.66 to 100.00 Hz by measuring the input signal of each circuit and the voltage change in the primary coil of the transformer. Results show that the DC power circuit can attain a maximum error rate of 5.15% at higher operating frequencies, whereas the AC power circuit displays a negligible agreement with the operating signal at frequencies greater than 33.33 Hz. Therefore it is confirmed that DC-powered ignition circuit is preferable for the PDE operating at high frequencies.

• Journal of the Korean Chemical Society
• /
• v.48 no.1
• /
• pp.12-16
• /
• 2004

The ignition of ethanol-oxygen-argon mixture was studied in reflected shock waves over the temperature range of 1281-1625 K and the pressure range of 0.69-1.06 bar. The ignition delay time was measured by the sudden increase of pressure profile and the radiation emitted by OH radicals. The relationship between the ignition delay time and the concentrations of ethanol and oxygen was determined in the form of mass-action expressions with an Arrhenius temperature dependence. In contrast to the behavior observed in methanol, ethanol acts to inhibit rather than accelerate its own ignition. Several kinetic mechanisms proposed for ethanol oxidation at high temperatures have been tested by the computer simulation.

• Journal of Biosystems Engineering
• /
• v.12 no.1
• /
• pp.45-52
• /
• 1987

In order to improve the thermal efficiency of an internal combustion engine, various ignition timing control systems were examined and the best one was chosen. The parts used for the systems were a microcomputer system with DAS, 8 bit output port (D-FLIP FLOP), three types of isolation circuit, two types of ignition timing pulse generator, three types of switching circuit and two types of high voltage ignition circuit. Most systems did not operate well due to the effects of electromagnetic waves and surge currents occurring when the ignition began or ended with resulting high voltage. The best ignition timing control system was found to be the combination of (microcomputer system)-(ignition timing pulse generator using step motor position control pick-up)-(switching circuit using TR logic)-(high voltage ignition circuit using CDI).

• Fire Science and Engineering
• /
• v.24 no.1
• /
• pp.116-121
• /
• 2010

The present study has been performed to investigate the ignition characteristics of a n-dodecane fuel droplet on the hot surface. Simplified bench scale test setup was built to examine the effect of air flow on the ignition temperature of fuel droplet. IR pyrometric sensor was used to measure the surface temperature, the measured temperature using IR pyrometer was directly compared with k-type thermocouple. The ignition of n-dodecane fuel droplet was divided into two stage - cool flame and hot flame - with the air flow rate except the case of air flow rate 3.0 lpm. The ignition temperature and probability was greatly affected by the air flow rate and the MHSIT of the present study was about $300^{\circ}C$ for air flow rate of 0.5 lpm.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.15 no.4
• /
• pp.223-229
• /
• 2022

In this paper, the ignition trans used in boilers was studied. Regardless of the change in the ignition rod length and the ignition rod gap, the output frequency was measured between 59.5 and 61.3 Hz, and it was found that the low frequency circuit operated normally. When the ignition rod gap changed by 2 to 10 mm, the ignition rod length was measured from 2.8A to 3.45A at 30cm. The ignition rod length was measured from 9.37 A to 14.5 A at 500 cm and from 13.2 A to 32.6 A at 1000 cm. As the ignition rod length and the ignition rod gap increased, the current increased. As a result of measuring the secondary coil output voltage. The ignition rod length was measured from AC 0.84 kV to AC 1.75 kV at 30 cm, AC 1.17 kV to AC 1.944 at 500 cm, and AC 1.4 kV to AC 7.18 kV at 1000 cm. As the ignition rod length and the ignition rod gap increased, the output voltage of the secondary coil also increased. As a result of measuring the output voltage of the ignition trans, the ignition rod length was measured from DC 1.11 kV to DC 1.57 kV at 30cm, DC 2.49 kV to DC 3.72 kV at 500cm, and DC 3.78 kV to DC 9.42 kV at 1000cm, and the power voltage increased as the ignition rod length and interval increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.252-255
• /
• 2007

Recently military industrial company, utilizing company funded R&D and goverment and industry contracts, has developed ACTS/DACS technology. This technology can be utilized to rapidly steer "smart" bullets, "smart" rounds, tactical missile, cruise missile and kill vehicles for both endo- and exoatmospheric applications. The ACTS/DACS typically consists of a Smart Bus Controller(SCB), a proprietary network firing bus, Smart Pyrotechnic Devices(SPD), rocket motors, and a structure. The SCB communicates with the SPDs over the propretary network firing bus. Each rocket motor contains an SPD which provides rocket motor ignition. Firing energy is stored locally in the SPD so surge currents do not occur in the system as rocket motors are fired. This approach allows multiple, truly simultaneous firings without the need for large, dedicated batteries. Each SPD also functions as a network tranceiver and high reliability fir set all in the space of a single-sided 10 millimeter diameter circuit. The present work develops a new means for igniting explosive materials. The volume of semiconductor bridge (SCB) is over 30 times smaller than a conventional hot wire. We believe that the present work has a potential for development of a new igniter such as smart pyrotechnic device.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.5
• /
• pp.393-401
• /
• 2018

Reliability prediction of an electronic arm fire device(EAFD) was studied which is applied to prevent accidental ignition in a solid rocket motor. For predicting the reliability, the main components of the EAFD were first defined(Control unit, LEEFI, TBI) and the operating principle of each component was analyzed. Performance modeling of each part is established using selected input variables through system analysis. When complex analysis is required, we approximated it with polynomial equation using response surface method. Monte-Carlo simulation is applied to performance modeling to estimate the design reliability.

• Journal of the Korean Institute of Gas
• /
• v.1 no.1
• /
• pp.106-112
• /
• 1997

This study measured the ignition limits of methane-air, propane-air, ethylene-air, and hydrogen-air mixture gases by discharge spark of D.C. power resistive circuit. The used experimental device is the IEC type spark ignition test apparatus, it consists of explosion chamber and supply -exhaust system of mixture gas. Mixture gases (methane-air, propane-air, ethylene-air, and hydrogen-air) were put into explosion chamber of IEC type spark ignition test apparatus, then it was confirmed whether ignition was made by 3,200 times of discharge spark between tungsten electrode and cadmium electrode. The ignition limits were found by increasing or decreasing the value of current. For the exact experiment, the ignition sensitivity was calibrated before and after the experiment in each condition. The ignition limits were found by changing the value of concentration of each gas-air mixture in D.C. 24 [V] resistive circuit. As the result of experiment, it was found that the minimum ignition limit currents exist at the value of methane-air 8.3 [$Vol\%$], propane-air 5.25[$Vol\%$], ethylene-air 7.8 [$Vol\%$], and hydrogen-air 21[$Vol\%$] mixture gases. For each the minimum ignition concentration of gases, the relationships between voltage and minimum ignition current were found. The results are as follows. - The minimum ignition limits are decreasing in the order of methane, propane, ethylene, and hydrogen. - The value of ignition current is inversely proportional to the value of source voltage. - The minimum ignition limit currents increase sharply at more than 2 [A]. The reason is caused by overheating the electrode.