• Transactions of the Korean Society of Mechanical Engineers
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• v.1 no.4
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• pp.182-189
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• 1977

The propagating flame temperature of the Propane-Air premixture by using 30.$\mu$ and 50.$\mu$ diameter platinum sensing wires, that is, Two Wires Correction Method, Through the constant volume burining inside the 150mm diameter, 30mm height combustion chamber under the circumstances of the atomospheric pressure, and the room temperature was determined. Also the temperature distribution across High Temperature Region, i.e. Flame Front, and the temperature profile behind the flame the front have been obtained.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.05a
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• pp.267-270
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• 2005

The purpose of this study was to make clear the indoor environmental efficiency of front balcony 'in apartment houses during winter. The field measurements of indoor environmental elements were carried out at an ordinary house with an existing front balcony and a house renovated the front balcony into the living room. The measurements in two-subject houses were taken on simultaneously the 20$^{th}$ ${\sim}$ 21$^{th}$ of January 2003. As results, the averages indoor temperature in the ordinary house and the renovated house were same as 23.6${\circ}$C, and the averages globe temperature in two houses were same as 23.7${\circ}$C. But, estimated heating time of the renovated house was longer than that of the ordinary house. The daily ranges of indoor temperature and globe temperature in the renovated house were wider than the ordinary house. The daily ranges of indoor temperature and globe temperature in the renovated house was longer than that of the ordinary house. The uniformity ratio range of daylight in the ordinary house were calculated at 1/3.4${\sim}$1/6.2, but those of the renovated house were 1/6${\sim}$1/16.2. Therefore. it was found that indoor temperature, globe temperature and uniformity ratio of daylight in the ordinary house maintained more constant than the renovated house by green house effect and earning effect of front balcony.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.1-9
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• 2001

The soot yield has been studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effects of pressure, temperature and turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. The pressure and temperature during soot formation are changed by varying the initial charge pressure and the volume fraction of inert gas compositions, respectively. It is found that the soot yield increases with dropping temperature and rising pressure at constant equivalence ratio, and that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.116-121
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• 2021

A lot of research is being done to develop a high-efficiency heat pump to save energy, and research to reduce or eliminate the phenomenon of frost occurring in the outdoor unit coil is also being conducted at the same time. A curved constant temperature chamber was constructed that can be tested under the same conditions as in the natural state so that the research can be conducted in which frost does not occur on the outdoor unit of the heat pump regardless of the season. Simulations were performed to verity whether such a curved constant temperature chamber has feasibility as an experimental device. For CFD conditions, the length of the straight duct in front of the outdoor unit located in the duct-type constant temperature chamber was 1, 5, 10 and 15 times the diameter of the duct. As a result, it was found that a straight space must be secured 10 times the diameter of the duct.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.889-898
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• 2003

The soot yield is studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effect of turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures and high temperatures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. It is found that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.391-397
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• 2006

The soot yield has been studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effect of pressure, temperature and turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degrees intervals in order to observe the soot formation under high temperature and high pressure. The eight converged flames compress the end gases to a high pressure. The laser schlieren and direct flame photographs with observation area of 10 mm in diameter are taken to examine the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in-situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. The changes of pressure and temperature during soot formation are controlled by varying the initial charging pressure and the volume fraction of inert gas compositions, respectively. It is found that the soot yield increases with dropping the temperature and raising the pressure at a constant equivalence ratio, and the soot yield in turbulent combustion decreases as compared with that in laminar combustion because the burnt gas temperature increases with the drop of heat loss for laminar combustion.

• Solar Energy
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• v.18 no.2
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• pp.91-104
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• 1998

This study carried out a numerical analysis on a heat pump assisted dryer using HFC134a. Under the constant degree of superheat and that of subcooling, we analyzed the performance of heat pump assisted dryer with varying an air mass velocity, bypass air ratio, compressor speed and an inlet bulb temperature of dryer. Simulation results were compared with experimental results, so they were maximally agreed in the range of 10%. There was the proper bypass air ratio with varying an air mass velocity. As for the effect of SMER having the inlet temperature $35^{\circ}C$ and compressor speed 1360rpm, bypass air ratio was 30% at the front velocity 0.5kg/s, 40% at the front velocity 0.7kg/s and 50% at the front velocity 0.9kg/s and 1.1kg/s. As the compressor speed was increased, SMER decreased and COP increased. As the inlet bulb temperature was increased, SMER and COP decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.213-218
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• 1992

The reaching time to the freezing point was to be fast in the order of 2% agar gel, 5% agar gel, 20% gelatin gel, pork, respectively. The freezing time and the passing time through the zone of the maximum ice crystal formation had linear relationship with the coolant temperature. The average diameter d$_{p}$ of ice crystal in a soybean protein gel and the moving of freezing front were represented an inverse proportion, and the moving velocity of freezing front was shown as 3.4$\times$10$^{-6}$ $\textrm{cm}^2$/sec from predicted theoretical formula. This value was very close to experimental results. The storage temperature did not give any influences for the growth of ice crystal in inside soybean protein gels during freezing conservation. The relationship between freezing condition and structure of freezing front was as follows : (moving velocity of freezing front) : (mass transfer rate of water at freezing point)$\times$(surface area of freezing front).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.528-536
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• 1999

This work studies the effects of transient reflectance on the thermal responses of a metal(gold) thin-film during ultrashort laser heating. The heating process is calculated using the conventional conduction model (parabolic one-step: POS), parabolic two-step model (PTS) with and without variable properties, hyperbolic two-step model (HTS). Results from the HTS model are very similar to those from the PTS model, since the laser heating time in this study is greater than the electron relaxation time. PTS model with variable properties, however, results in totally different temperature profiles compared to those from POS models or calculation with constant properties. Transient reflectances are estimated from electron temperature distributions and based on the linear relationship between the electron temperature and complex dielectric constants. Reflectance of the front surface can be changed with respect to dielectric constants, while those of the rear surface remain unchanged.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.38-47
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• 1999

An improved one-dimensional modeling of snow melting was obtained by considering both the effect of heat capacity and the decreasing influence of porosity. Using the improved model, the effects of initial snow temperature, initial snow density and the heat flux on the snow melting were investigated. It is found that the drainage starting time is delayed and the drainage rate becomes smaller with lower initial snow temperature. ResuIts also show that the drainage starts at the same time when an initial snow density is over a certain value. Melting efficiency increases linearly with an increasing initial snow temperature. With increasing the initial density of the snow and the amount of heat supplied, the melting efficiency increases, then converges to a constant value.