• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.121-128
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• 2005

This is about experimental comparison study between convective heating and radiation heating system to use the design criteria for residential house. Experiment was done in EC(environment chamber) under simultaneous outdoor condition for 4 kinds of heating system such as CRHP(Ceiling Radiant Heating Panel), BEHC( Bottom Electric Heating Coil Mat), EFCU( Electric Fan Coil Unit) and CEHU( Convective Electric Heating Unit). Result show that CRHP ,which is radiation heating system, can consume more 23% energy than convective heating system when it is operated by dry bulb temperature but can save 1 ${\sim}$ 10% when operated by glove temperature and 27% when operated by MRT.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.145-150
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• 2009

In this study, characteristics of microwave and convective drying are studied by using a multiphase porous media model. Temperature and moisture profiles for hot-air convective heating and microwave heating of 1-D porous media with varying time and space are numerically investigated. This result shows the microwave drying method is more effective than the convective drying method. Comparing to convective drying, microwave drying can increase temperature and evaporation rate significantly since microwave generates internal heat and increases internal pressure, which results in moisture movement toward the surface on which moisture is vaporized.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.570-577
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• 2007

A micromachined convective accelerometer is a recently developed device. Typical micromachined accelerometers use a solid proof mass for measuring acceleration. But a micromachined convective accelerometer does not use a solid proof mass. A micromachined convective accelerometer is composed of a heating resistor and temperature sensors. This device measures acceleration by using convective heat transfer phenomenon. Therefore characteristics of a micromachined convective accelerometer are different as compared with typical micromachined accelerometer. In this research, we analyze the convective accelerometer by using transient convective heat transfer analysis. Based on the results of a convective accelerometer, we propose a new model which has improved performance.

• Journal of the Korean housing association
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• v.6 no.1
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• pp.31-37
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• 1995

The purpose of this study is to analyse the distribution of thermal sensation response and thermal environment condition in convective heating space. The contents of this study are as follows: 1)the spatial distributions of thermal conditions are measured 2)the thermal sensation vote of residents is taken in order to investigate the relation between thermal condition and human thermal sensation in sedentary condition 3)to analyse the distribution of subject's thermal sensation vote and thermal environment condition by two methods-regression method and graph method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.450-458
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• 2000

This study deals with the unsteady close-contact melting of solid blocks on a flat surface subject to convective heating. Normalizing the model equations in reference to the steady solution successfully leads them to cover constant heat flux and isothermal limits at small and large extremes of the Biot number, respectively. The resulting equations admit a compactly expressed analytical solution, which includes the previous solutions as a subset. Based on the steady solution, the characteristics of close-contact melting can be categorized into constant heat flux, transition, and isothermal regimes, the boundaries of which appear to be nearly independent of the contact force. The unsteady solutions corresponding to Biot numbers in the transition regime show intermediate behaviors between those of the two limits. With a proper approximation, the present solution procedure can cope with the case of variable fluid temperature and heat transfer coefficient. Regardless of imposed conditions, the mean normalized Nusselt number during the unsteady process asymptotically approaches to a constant value as the Biot number comes close to each limit.

• Journal of computational fluids engineering
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• v.12 no.4
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• pp.7-13
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• 2007

Numerical analysis is carried out for combined heat transfer in an indirected NIR(Near Infrared Ray) heating chamber. Reynolds number and shapes of absorbed cylinder are known as important parameters on the combined heat transfer effects. Reynolds number based on the outer diameter of the cylinder is varied from $10^3$ to $3{\times}10^5$. Four difference heat transfer regimes are observed: forced convection and radiative heat transfer on the outer surface of the cylinder, pure conduction in the cylinder body, pure natural convection and radiation between lamp surface and inner surface of the cylinder, and radiation from the lamp. Flow and temperature characteristics are presented with iso-contour lines for the absorbed circular and elliptic cylinders to compare their differences. The convective and radiative heat transfer fluxes are also compared with different Reynolds numbers. As usual, Reynolds number is an important factor to estimate increasing convective heat transfer as it increases. The shape of absorbed cylinder results overall heat transfer rates remain unchanged.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.118-123
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• 2000

This experimental study was conducted to figure out the characteristics of convective heat transfer in non boiling vertical downward flow with polymer additives. This experiment was studied in 26mm diameter, 800mm heating length and $1{\times}10^5W/m^2$ heat flux. The polymer concentration ranged from 0PPM to 500PPM with corresponding from Reynolds number $3.3{\times}10^4$ to $6.8{\times}10^4$ in non boiling vertical downward flow. Experimental results show that the characteristics of convective heat transfer was a strong function of polymer concentration and it has decreased with increasing the polymer concentration in non boiling vertical downward flow.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.703-707
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• 1989

The ignition of solid particle under strong convective heating has been investigated by applying an asymptotic analysis to a semi-infinite body for varying values of gas recovery temperature and convective heat transfer coefficient. It was found that if the scale of the reaction zone is much smaller than the characteristic length of the body size, then infinite body theory can be used to estimate the ignition delay time. Furthermore, the convective heat transfer coefficient was found to have more influence on predicting the ignition delay times of particle exposed to an incident shock wave rather than the gas recovery temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.12
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• pp.1275-1281
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• 2001

Aqueous polymer solutions are known to have small pressure reduction. Paraffin slurries are known to have high thermal capacity. Paraffin particles are mixed into an aqueous polymer solution to make a new heat transfer fluid having high thermal capacity but low pressure reduction. The heat transfer characteristics of the new slurry was tested in a circular tube having a constant heat transfer boundary condition. The new slurry was found to have high Nusselt numbers as well as high thermal capacity and low pressure reduction in the laminar flow. The trends of the Nusselt numbers along the heating test section were studied for various heating conditions.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1996.04a
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• pp.30-30
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• 1996