• Title/Summary/Keyword: wind-heat

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Characteristic of the Ion Wind Using Corona Discharge and Enhancement of Heat Transfer (코로나 방전을 이용한 이온풍의 특성분석 및 열전달 향상)

  • Lee Jae-Il;Hwang Yu-Jin;Joo Ho-Young;Ahn Young-Chull;Shin Hee-Soo;Lee Jae-Keun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.1022-1027
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    • 2005
  • An experimental study is conducted to investigate the characteristics of the ion wind generated by the electric field between a needle electrode and the parallel plate electrodes. The ion wind enhances heat and mass transfer between the surface and the surrounding gas. Moreover such enhancement makes no noise or vibration. This study is conducted to develop the electronic cooling device. The measured gas velocities and heat transfer coefficients are proportional to the applied voltage. The heat transfer coefficient can be increased as compared with a natural convection. The maximum enhancement of heat transfer obtained in this system is $47\%$ for 3 W in heat transfer rate.

An Experimental Study on Heatsink Temperature Distribution according to the Wind Speed of a 30W LED Floodlight (30W급 LED 투광등의 풍속에 따른 히트싱크 온도분포에 관한 실험적 연구)

  • Lee, Young Ho;Kim, Dae Un;Chung, Han Shik;Jeong, Hyo Min;Yi, Chung Seob
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.5
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    • pp.96-102
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    • 2019
  • This study investigated the heat dissipation characteristics of a heat-sensitive LED. More than 80% of the power supply is converted into heat energy, which has a fatal impact on the lifetime of the LED. Therefore, the effective heat dissipation characteristics of a heatsink, such as a 30W floodlight, through forced convection were grasped and the heat transfer characteristics were tested. As a result, it was confirmed that the smaller the number of fins, the more the temperature distribution varies according to the wind velocity. In addition, the larger the number of fins, the smaller the temperature difference according to the wind velocity. Therefore, it was found through this experiment that excellent heat dissipation performance was exhibited as the heat dissipation area and wind velocity increased.

Forced Convection Heat Transfer from an Inner Surface of a Two-Dimensional Rectangular Cavity (이차원 사각형 공동 내부에서의 강제 대류 열전달)

  • Seo, T.B.;Han, K.Y.;Kange, Y.H.
    • Journal of the Korean Solar Energy Society
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    • v.22 no.4
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    • pp.77-84
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    • 2002
  • In order to investigate forced convection heat transfer due to the wind from the inner surface of a cavity receiver for a parabolic dish type solar energy collecting system, a two-dimensional rectangular cavity receiver is prepared and installed in a wind tunnel. The convection heat transfer coefficient of the inner surface of the receiver is dependent on the direction and the velocity of the wind. The attack angle of the cavity and the air velocity in the tunnel are controlled in a wide range so that the effects of the attack angle and the wind velocity on the heat transfer coefficient can be studied. The skirt is installed at the aperture of the cavity in order to reduce convective heat loss. The effects of the length and the installation angle of the skirt on convection heat transfer of the cavity are tested. It is found that convection heat loss can be significantly reduced by installing the skirt. Also, it is known that heat transfer from the cavity can be minimized if the angle of the skirt is $90^{\circ}$ to the outer surface of the cavity.

ACCURATE ESTIMATION OF GLOBAL LATENT HEAT FLUX USING MULTI-SATELLITE DATA

  • Tomita Hiroyuki;Kubota Masahisa
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.14-17
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    • 2005
  • Global latent heat flux data sets are crucial for many studies such as those related to air-sea interaction and climate variation. Currently, various global latent heat flux data sets are constructed using satellite data. Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO) includes one of the satellite-derived global latent heat flux data (Kubota et aI., 2000). In this study, we review future development of J-OFURO global latent heat flux data set. In particular, we investigate usage of multi-satellite data for estimating accurate global latent heat flux. Accurate estimation of surface wind speeds over the global ocean is one of key factors for the improved estimation of global latent heat flux. First, we demonstrate improvement of daily wind speed estimation using multi-satellites data from microwave radiometers and scatterometers such as DMSP/SSMI, ERS/AMI, QuikSCAT/SeaWinds, AqualAMSR-E, ADEOS2/AMSR etc. Next, we demonstrate improvement of global latent heat flux estimation using the wind speed data derived from multi-satellite data.

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Numerical Simulation of Effect of Urban Land-use Type and Anthropogenic Heat on Wind Field (지표면 변화와 인공열이 바람장에 미치는 영향에 관한 수치 시뮬레이션)

  • 홍정혜;김유근
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.5
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    • pp.511-520
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    • 2000
  • The urban atmosphere is characterized by th difference in surface and atmospheric environment between urban and more natural area. To investigate th climatic effect of land use type and anthropogenic heat of urban on wind field, numerical simulations were carried out under typical summer synoptic condition. The wind model PNU_MCM(Pusan National University Mesoscale Circulation Model) is based on the three-dimensional Boussinesq equations, taking into account the hydrostatic assumption . Since lane-use differs over every subdivision on Pusan the surface energy budget model includes sub0grid parameterization scheme which can calculate the total heat flux over a grid surface composed of different surfaces. The simulated surface wind agrees well with the observed value, and average over 6 days which represent typical summer lan-sea breeze days, August 1998, i.e. negligible gradient winds and almost clear skies. Urbanization makes sea-breeze enhance at day and reduce land-breeze at night. The results show that contribution of land-use type is much larger than that of anthropogenic heat in Pusan.

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An Experimental study on Heat Transfer Characteristics of Horizontal Liquid Film Driven by Hot Wind (유동고온공기에 의해 유인되는 수평평판 액막류의 열전달에 관한 실험적 연구)

  • Park, J.H.;Park, S.K.;Yoon, S.H.;Oh, C.;Kim, M.H.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.83-88
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    • 2002
  • This study is to provide the experimental information and basic data on heat transfer characteristics of horizontal liquid film driven by hot wind. Heat transfer characteristics of the liquid film in the rectangular duct was observed and the change of film temperature was measured. The experiments were carried out for a variety of parameter, such as feed water rate and velocity and temperature of feed air. From the observation and the measurement the general understanding of heat transfer characteristics for liquid film driven by hot wind was provided.

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Performance Measurement of the Eddy Current Heat Generator with Different Array of Permanent Magnets (서로 다른 자석 배열을 가지는 와전류 열원화 장치의 성능 측정)

  • Yun, Teak-Han;Son, Young-Woo;Lee, Jang-Ho
    • New & Renewable Energy
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    • v.9 no.1
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    • pp.17-24
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    • 2013
  • Eddy Current is one of ways to make heat using rotational energy of wind turbine rotor. Four difference arrays of permanent magnets around rotor surface are used to generate heat using eddy current in this study. For the evaluation of heating performance, new test rig is prepared to measure water flow and temperatures in the inlet and outlet of the eddy current heat generator. In the test, torque and rotational speed are also measured in the motor driven system, and evaluated if the torque is matched with it of wind turbine rotor or not. It will be shown that the eddy current heat generator can be applied to real urban wind energy systems in this study.

A Study on the Relation of Urban Heat Island and Air Pollution in Seoul Area (서울지역의 도시열섬현상과 대기오염도의 관계에 관한 연구)

  • 장영기;김정욱
    • Journal of Korean Society for Atmospheric Environment
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    • v.7 no.1
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    • pp.49-53
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    • 1991
  • Relations of urban heat island and air pollution are analyzed by using $SO_2$ concentration data (winter season in 1985) from 10 sites of Seoul area and differences of wind speed and air temperature in urban and rural area. Urban heat island is developed when daily mean wind speed at urban site is lower than 1.5m/sec or in the interval of 3.0 $\sim$ 3.5m/sec. When differences between urban and rural air temperature is greater than the overall average of those differences, $SO_2$ concentrations of those above-average differences are 1.3 $\sim$ 1.8 times higher than those of below-average differences. The trends are shown obviously at north-eastern area of Seoul (Gilum Dong, Ssangmun Dong, Myeonmog Dong). When intensity of Urban Heat Island is weak, $SO_2$ concentration was reduced in propotion to a rise of wind speed. But $SO_2$ concentration is on the partial increase in spite of a rise of wind speed when intensity of urban heat island is strong.

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A Literature Study on Acute Laryngitis (급성(急性) 후두염(喉頭炎)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Jung, Chang-Ho;Kim, Yun-Hee
    • Journal of Haehwa Medicine
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    • v.14 no.1
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    • pp.113-128
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    • 2005
  • 1. Acute laryngitis is a hoarse voice or the complete loss of the voice because of irritation to the vocal folds. 2. Acute laryngitis belongs with the GeupHuEum, HuBi, HuPung in oriental medicine. 3. GeupHuEum is caused by wind and cold, weak of lung and kidney, evil energy of liver, sore throat, etc. It is treated with the methods of cooling lung and wetting, removing heat and changing phlegm, etc. 4. Hubi is caused by fire and wind, dampness, large lung. It is treated with the methods of removing heat and antidote, reinforcing and descending fire, bleeding by acupuncture, vomiting. 5. Hupung is caused by phlegm and heat of lung and stomach, wind and heat. It is treated with the methods of dispersing wind and removing heat and changing phlegm by medicine, acupuncture, moxibustion, vomiting, fumigation.

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The Oriental and Occidental bibliographic Study of Psoriasis (乾癬에 對한 東.西醫 文獻的 硏究)

  • Kim, Nam-Kwen;Hwang, Chung-yeon;Lim, Gye-sang
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.12 no.1
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    • pp.154-178
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    • 1999
  • Psoriasis is the recurrent disease of skin and till now its mechanism, pathogenesis and treatment are not clearly discovered. So, like these papers, we must investigate more safety and effective treatment of psoriasis. And I obtained the following condusions from the Oriental and Occidental bibliographic investigation. 1. In Oriental medicine. Baikbi, Pungsun, Eunselbyong, Songpisun, Baikselpung were the other names of Psoriasis. 2. In Occidental medicine, genetic factors, aggravation and inducible factors, biochemical factors, immunologic factors, disorder of epidermal kinetics, vascular malformation of dermis were cosidered to the pathogenic factors of psoriasis. 3. In Oriental medicine, the pathogenic factors of psoriasis were divided two parts. One is exogenous pathogenic factors which including the blood-heat, blood dryness, blood stasis, deficiency of liver and kidney, inharmony of impulsive and appointed pulsation, deficiency of blood. The other is exogenous pathogenic factors which including the wind-evil, wind-wetness, wind-heat, wind-cold, wetness-heat, cold-wetness, heat-evil. 4. In Occidental medicine, external applicative medicine, internal medicine, ultraviolet therapy, ultraviolet - external applicative medicine compound therapy and etc. were used the therapy of psoriasis. 5. In Oriental medicine, clean away heat and cooling blood, aliment the blood and moisturize, activating blood and expelling blood stasis, harmonize and invigorate the liver and kidney, invigorate the kidney, aliment the blood and moisturize the skin, aliment the blood and expelling the wind, expelling the wind and wetness, clean away heat and expelling wind, expelling the wind and scatter the cold, clean away heat and expelling the wetness, heat up the meridian and scatter the cold, clean away heat and remove the toxin and etc. were used the method of internal therapy of psoriasis. 6. Until Qing dynasty, wind expelling effective prescriptions like Bangpungtongsungsan, Sopungsan. Supungsunkisan and etc. were used and recently Yanghyelgeupungtang, Hwalhyelgeupungtang, Samultanggagam and etc. were used the internal therapy of psoriasis. 7. In the external therapy of psoriasis, Yuhonggo, Pungyugo, Sekryupiyeongo were used the plaster therapy and Folium Rerillae, Camphora, Fructus, Xanthii, Herba Spirodelae compound prescription were used the cleansing therapy, Okgisan, Chiunsan, Galmyogo, Hobunsan, Muisan, Madugo, Jeyugohengin were used the rubbing skin therapy. Rangdok Radix Aconiti, Bijeonilchoalkwang were used the attaching therapy, the extract of Rhizoma Et Radix Veratri was used the spreading pouder therapy. 8. In the acupuncture therapy of psoriasis, the Jelgol, chok Samni(S36), Kansa(P5), Haegye(S41), Wijung(B40) and etc. were used the acupuncture point, and the angle of helix incision threapy that disinfect and cut the angle of helix and plaster the Semen Glycine and Squama Manitis were used.

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