• Journal of the Korean Society of Combustion
• /
• v.21 no.2
• /
• pp.7-14
• /
• 2016

Evaporation and combustion characteristics of fuel droplet with carbon nanoparticle were investigated in a rapid compression machine(RCM). RCM is an experimental equipment to simulate one compression stroke of reciprocating engine. Nitrogen was charged into reaction chamber for evaporation experiment, while oxygen was charged for combustion experiment. N990 carbon black and n-heptane were used to synthesize the carbon nanofluids. Surfactant, span80, was used to make synthesis easier. The droplet pictures were taken using a high speed camera with 500 frames per second. Thermocouple, of which tip is $50{\mu}m$, was used not only to measure transient bulk temperature, but also to suspend the droplet. Reaction chamber temperature was calculated from pressure data. The evaporation rate of nanofluids was improved compared to pure fuel. The ignition delay was promoted due to the nanoparticle, but the burning rate was decreased.

• Fire Science and Engineering
• /
• v.24 no.1
• /
• pp.111-115
• /
• 2010

For the development of fire detector equipments that was fused independent type of fire detector and a wireless communication function, this paper adopted a signal processing method of an independent formation fire sensor by a ZigBee communication method, and it was designed that the combinations of fire detector and wireless communications network were enabled. When a fire occurred, output voltage of a fire detector was 0.4 V, the movement pulse width was $600{\mu}s$, and that was confirmed by an experiment. When it has lookout state, LED worked by 30 s cycle and working current is 0.12 mA. When a fire occurred, LED worked by 0.5 s cycle and working current was 7 mA, and through this experiment of power source, Chamber tester, smoke tester,IRED, LED lighting, the propriety of the method that we showed in this paper confirmed.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.1174-1179
• /
• 2006

This study aims to reduce the pollutant emission for improving the IAQ by finishing with natural materials. To investigate the concentration of pollutants such as Vocs, HCHO, both the chamber experiment and field measurement were conducted. The results of the study can be summarized as flows. (1) According to the chamber experiment of pollutant-emitting porwer of diatomite materials showed that VOCs and formaldehyde emission rates were lower and satisfied to the most on the HB Grade. (2) The field measurement of pollutant-emitting concentration of clay materials were lower 35% than other materials. (3) The Vocs and formaldehyde were most emitted from furnitures and the emission rate were found to be proportional to indoor air temperature. To control the emitted pollutants efficiently, the reasonable selection of finishing with natural materials are required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.6 s.121
• /
• pp.612-619
• /
• 2007

In this paper, a Four-wired antenna was designed and manufactured using Four-wires in order to perform EMI/EMC experiments. As compared with a TEM cell, the feature of the Four-wired antenna has simple installment with broadband balun, a Four-wired antenna, and loading resistances in an anechoic chamber. And the E-field polarization of antenna can be easily changed. Without the limitation of space, EMI/EMC experimental environment could be built within the anechoic chamber with the moderate cost. In S, C, and X-bands, the manufactured antenna was able to make an experiment on EMI/EMC with the DUT which has the quiet zone of the height, width, length equal to about 10 cm.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.11
• /
• pp.1457-1463
• /
• 2000

Experimental studies on determination of the supply leading time of propellants to combustion chamber have been made to stably and efficiently guarantee the ignitions process with liquid rocket engine. The propellant used is a Kerosene as fuel and a liquid oxygen as oxidizer. FOOF type of three injectors are set with an angle of 135。 and the combustion chamber pressure is 200psi. The present experiment program also includes the stability on the quadlet type of ignitor using the triehylaluminum (TEAL) as an ignition source. Experimental results clarifies that the propellant supply through LOx leading to combustion chamber is proper for stable ignition and combustion processes based on the fuel and oxidizer manifold pressures, combustion chamber pressure, and the variation of flame length from the nozzle exit with lapse time, and shows that the leading supply time pf propellants effects the engine performance little.

• Journal of Sensor Science and Technology
• /
• v.13 no.4
• /
• pp.258-263
• /
• 2004

In this study, we carried out a basic study for the development of optical transcutaneous $pCO_{2}$ gas sensor and analyzer using non-invasive method. The basic principle of $pCO_{2}$ measurement is adapted Beer lambert's law and embodied the system using NDIR method. This measuring system was composed of a IR lamp, a optical filter, a optical reaction chamber, pyroelectric sensor and a signal process. We measured $EtCO_{2}'s$ concentration in basis step instead of $pCO_{2}$ gas that can collect by inflicting heat in outer skin. We minimize the size of optical reaction chamber which takes up the largest volume, to make the portable sensor. We made optical reaction chamber in Si wafer using MEMS technology and the optical reaction chamber was shortened to 2 mm and we carried out an experiment. When we injected the $EtCO_{2}$ to the inside of the optical reaction chamber, we could confirm change of 4.6 mV. The system response time was within 2 second that is fairly fast.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.869-872
• /
• 2005

The purpose of this study is on the prediction of the acoustic performance of the lined rectangular plenum chamber which can be used in the HVAC systems. The lined plenum chamber is modeled as a piston driven rectangular tube without mean flow and the acoustic pressure in the lined chamber is obtained by superposing the three dimensional pressure due to each of uniformly and harmonically fluctuating pistons. The arbitrary locations of inlet/outlet ports as well as the acoustic higher order modes generated at the area discontinuities of the port chamber interfaces are taken into consideration. The four-pole parameters can be derived by imposing the proper boundary conditions on each inlet and outlet ports. The lining material on the internal wall is assumed to be a bulk-reacting model. A single weak variation statement which satisfies the fluctuating rigid piston condition and the pressure and displacement continuity condition at the interface between the lining material and the airway was developed. The set of cosine functions were used as the admissible function when applying the Rayleigh-Ritz method. Computed results are compared with those predicted by using the locally-reacting lining material and experimental results, respectively. There are a good agreement shown between the results by the Rayleigh-Ritz method and the experiment results. The derived transfer matrices can be easily combined with other four-pole parameters of different types of mufflers for the calculation of the whole system performance.

• Journal of IKEEE
• /
• v.22 no.2
• /
• pp.302-308
• /
• 2018

Multi-Layer Sputtering is aim to develop desired thickness thin film multi-layer with different materials. The multi-layer thin film deposition process occupies a relatively large portion in the process time, because the main reason is that it takes much time to move the substrate to be deposited and to make the chamber into a high vacuum state compared to the process time. Most of semiconductor and display industries sputter a single substance in one chamber and move boards through multi-continuous robots to another chamber to sputter other materials. This will inevitably require multiple chambers, vacuum pumps, and multi-contamination robots within the process facility. To solve these problems, this paper proposes a control system for multi-layer thin film sputtering devices that deposit different materials within a single vacuum chamber and is applied in TFT process. The manufacture and experiment of the control system proved its validity.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.4
• /
• pp.551-561
• /
• 1998

This paper was studied to understand the characteristics of heat transfer coefficients and surface temperature distributions around a circular combustion chamber within the heat-intercept duct of kerosene fan heater. The experiment was carried out in the heat-intercept duct of kerosene fan heater attached to the blow-down-type subsonic wind tunnel with a test section of 240 mm * 240 mm * 1200 mm. The purpose of this paper was to obtain the basic data related with normal combustion for new design from conventional kerosene fan heater, and to investigate the effect of surface temperature, local and mean heat transfer coefficients versus flow-rate of convection axial fan according to the variations of heat release conditions from kerosene fan heater during normal combustion. Consequently it was found that (i) the revolution of convection axial fan during combustion had a smaller value than that of non-combustion because of the thermal resistance due to the high temperature in the heat-intercept duct, (ii) the pressure ratio P$_{2}$/P$_{1}$ had a comparatively constant value of 0.844 according to the revolution increase of turbo fan and the heating performance of kerosene fan heater had a range of 1,494 ~ 3,852 kcal/hr, (iii) the local heat transfer coefficient around a circular combustion chamber had a comparatively larger scale in the range of 315 deg. < .theta. < 45 deg. than that in the range of 90 deg. < .theta. < 270 deg. as a result of heat transfer difference between front and back of a circular combustion chamber, and (iv) the mean heat transfer coefficient around a circular combustion chamber increased linearly like a H$_{m}$=95.196Q+104.019 in condition of high heat release according to the increase of flow-rate of axial fan.n.

• Current Optics and Photonics
• /
• v.1 no.3
• /
• pp.186-195
• /
• 2017

Obtaining accurate visibility measurements is a common atmospheric optical problem, and of vital significance to civil aviation. To effectively evaluate and improve the accuracy of visibility measurements, an outdoor atmospheric simulation chamber with dimensions of $1.8{\times}1.6{\times}55.7m^3$ was constructed. The simulation chamber could provide a relatively homogeneous haze environment, in which the visibility varied from 10 km to 0.2 km over 5 hours. A baseline-changing visibility measurement system was constructed in the chamber. A mobile platform (receiver) was moved from 5 m to 45 m, stopping every 5 m, to measure and record the transmittance. The total least-squares method was used to fit the extinction coefficient. During the experiment conducted in the chamber, the unit weight variance was as low as $1.33{\times}10^{-4}$ under high-visibility conditions, and the coefficient of determination ($R^2$) was as high as 0.99 under low-visibility conditions, indicating high stability and accuracy of the system used to measure the extinction coefficients and strong consistency between repeated measurements. A Grimm portable aerosol spectrometer (PAS) was used to record the aerosol distribution, and then Mie theory was used to calculate the extinction coefficients. The theoretical results were found to be consistent with the measurements and exhibited a positive correlation, although they were higher than the measured values.