• Title/Summary/Keyword: Air Temperature

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CFD ANALYSIS OF DISTRIBUTION OF AIR TEMPERATURE ON PLATFORMS OF A LARGE RAILWAY STATION IN SUMMER SEASON

  • Tsukamoto Kenji;Iino Akinaru;Tominaga Yoshihide
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.173-177
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    • 2005
  • The purpose of this study is to analyze the principal causes of increases in air temperature on platforms of railway station. We analyzed the distribution of air temperature on Shinkansen platforms at Station 'A' using Computational Fluid Dynamics (CFD). We focused on the factors that influence the temperature dynamics associated with heat generated by trains and station buildings and their effect on the ambient temperature on platforms. In the case of heat generated by trains, air temperature on Shinkansen platforms increased by 4 to 7 degrees compared to when trains generated no heat. When a 50-m high station building was located on the windward side of the platforms, air temperature on Platform X was 2 degrees higher than when the station buildings were absent. Air? temperature on platforms VII to IX increased progressively, and the maximum air temperature on platform VIII was 3 K higher than if station buildings were absent.

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Seasonal Variations of Stream Water Temperature and its Affecting Factors on Mountain Areas (산지계류의 계절적 수온변동 특성 및 영향인자 분석)

  • Nam, Sooyoun;Choi, Hyung Tae;Lim, Honggeun
    • Journal of Korean Society on Water Environment
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    • v.35 no.4
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    • pp.308-315
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    • 2019
  • The objective of this study was to investigate mountain stream water and air temperatures, area, latitude, altitude, and forest coverage in headwater catchments located in Kangwon-do, Mid-eastern Korea from 2015 to 2017. Daily mean value of mountain stream water temperature was approximately $6^{\circ}C$ lower than the daily mean value of air temperature on the monitoring sites during the observation period. Monthly mean value of mountain stream water temperature increased with increasing monthly mean value of air temperature from May to August during the observation period. Seasonal variations of mountain stream water temperature were dependent on air temperature rising and falling periods. Correlation analysis was conducted on mountain stream water temperature to investigate its relationship with air temperature, area, latitude, altitude, and forest coverage of air temperature rising and falling periods. The correlation analysis showed that there exists a relationship (Correlation coefficient: -0.581 ~ 0.825; p<0.05), particularly the air temperature showed highest correlation with mountain stream water temperature. Regression equations could be developed due to contribution of air temperature to affect mountain stream water temperature (Correlation coefficient: 0.742 and 0.825; p<0.01). Therefore, a method using various parameters based on air temperature rising and falling periods, could be recommended for predicting mountain stream water temperature.

An Experimental Study of Temperature Profiles in Mixing Zone of AHU with an Air Mixer (에어믹서가 설치된 공조기 혼합실 내의 온도분포에 관한 실험적 연구)

  • Pak, Kwon-Jong;Lee, Sek-Jun;Jang, Young-Keun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.12
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    • pp.999-1006
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    • 2006
  • A study of temperature profiles in mixing zone of AHU (air handling unit) can contribute greatly to enhance performance of AHU system, so the study on the temperature distribution between RA (return air) and OA (outdoor air) is important to analyze the mixing characteristics in a mixing zone of AHU. Accordingly, the temperature profiles during RA (return air) and OA (outdoor air) supply process into mixing zone of AHU with an air mixer are studied experimentally. The effect of air mixer, OA temperature and RA/OA flow rate are studied in detail. In this study, the results show that the mixing efficiency is all high for installed the air mixer. The more OA temperature increase and OA flow rate decrease, the more mixing efficiency is high.

Investigation of Urban High Temperature Phenomenon in Summer using the High Density Ground Monitoring System in Daegu Metropolitan Area (지상 고밀도 관측 시스템을 이용한 대구의 여름철 고온현상 조사)

  • Kim, Sang-Heon;Cho, Chang-Bum;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.23 no.9
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    • pp.1619-1626
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    • 2014
  • We analyzed diurnal variations in the surface air temperature using the high density urban climate observation network in Daegu metropolitan city, the representative basin-type city in Korea, in summer, 2013. We used a total of 28 air temperature observation points data(16 thermometers and 12 AWSs). From the distribution of monthly average air temperature, air temperature at the center of Daegu was higher than the suburbs. Also, the days of daily minimum air temperature more than or equal to $25^{\circ}C$ and daily maximum air temperature more than or equal to $35^{\circ}C$ at the schools near the center of Daegu was more than those at other schools. This tendency appeared more clearly on the days of daily minimum air temperature more than or equal to $25^{\circ}C$. Also, the air temperature near the center of the city was higher than that of the suburbs in the early morning. Thus it was indicated that the air temperature was hard to decrease as the bottom of the basin. From these results, the influence of urbanization to the formation of the daily minimum temperature in Daegu was indicated.

Comparative Study of Maximum Temperature Condition in Green Space (녹지 조건에 따른 최고기온의 비교연구)

  • 윤용한
    • Asian Journal of Turfgrass Science
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    • v.15 no.4
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    • pp.181-186
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    • 2001
  • In this study, we observed air temperature to make clear that land coverage condition and forest form has a certain relationship to air temperature in a day in various green space. And with revolution analysis, interpreted relationship of air temperature distribution in the green space, of land coverage rate and air temperature, of volume of tree and temperature. With this experimental result, propose green plan, taking into consideration lower effect of air temperature. In this result lower zone is formed in forest and water area, higher zone is done in paved surface and barren ground. And arbor+subarbor area, water area sur-rounded forest and small river is formed relative lower air temperature. In my opinion to promote efficiency lower air temperature area, it is need to make water area surrounded forest, to make forest form lower air temperature 2∼3 layer forest. Lower air temperature effect is in order of arbor, subarbor, shrub and is proportioned increasing of tree.

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AN EXPERIMENTAL STUDY OF THE EFFECT ON PULP TEMPERATURE DURING ABUTMENT PREPARATION (지대치 형성이 치수온도에 미치는 영향에 관한 실험적 연구)

  • Kim, Byong-Ki
    • The Journal of Korean Academy of Prosthodontics
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    • v.14 no.1
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    • pp.47-54
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    • 1976
  • Pulpal temperature is changed in response for various conditions which were mechanical, thermal, chemical and biological stimuli. This study was performed to determine the pulpal temperature changes which were using air turbine with air-water coolant, water coolant, and conventional dental engine with water coolant and no coolant on 28 canine of dogs. In order to record pulpal temperature, pulp chamber was opened on the labiocervical area of canine. Thermocouple was inserted into pulp chamber and was fixed with filling material(dycal). Changes of pulpal temperature were recorded on the physiograph, which had been standardized temperature degree, through thermocouple to thermistor bridge and carrier preamplifier. The amount of experimental temperature change to that of control was interpreted in the pulpal cavity. The obtained results were as followings: 1. The mean normal temperature was 33.07 centigrade. 2. The temperature was decreased than normal pulpal temperature. It was 12.04 centigrade in reduction by air turbine with air-water coolant, 7.17 centigrade in reduction by air turbine with air coolant, 5.54 centigrade in reduction by conventional engine with water coolant, and 1.26 centigrade in reduction by conventional engine with no coolant. 3. The time for maximal temperature change was 53.3 seconds in reduction by air turbine with air-water coolant, 73.4 seconds in reduction by air turbine with air coolant, 50.9 seconds in reduction by conventional engine with water coolant, and 27.1 seconds in reduction by conventional engine with no coolant. 4.. After reduction was ceased, the recovery time to normal pulp temperature was 287.1 seconds in air turbine with air-water coolant, 189.0 seconds in air turbine with air coolant, 86.9 seconds in conventional engine with water coolant, and 52.9 seconds in conventional engine with no coolant respectively.

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Estimation of the air temperature over the sea using the satellite data

  • Kwon B. H.;Hong G. M.;Kim Y. S.
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.392-393
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    • 2005
  • Due to the temporal and spatial simultaneity and the high-frequency repetition, the data set retrieved from the satellite observation is considered to be the most desirable ones for the study of air-sea interaction. With rapidly developing sensor technology, satellite-retrieved data has experienced improvement in the accuracy and the number of parameters. Nevertheless, since it is still impossible to directly measure the heat fluxes between air and sea, the bulk method is an exclusive way for the evaluation of the heat fluxes at the sea surface. It was noted that the large deviation of air temperature in the winter season by the linear regression despite good correlation coefficients. We propose a new algorithm based on the Fourier series with which the SST and the air temperature. We found that the mean of air temperature is a function of the mean of SST with the monthly gradient of SST inferred from the latitudinal variation of SST and the spectral energy of air temperature is related linearly to that of SST. An algorithm to obtain the air temperature over the sea was completed with a proper analysis on the relation between of air temperature and of SST. This algorithm was examined by buoy data and therefore the air temperature over the sea can be retrieved based on just satellite data.

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Analysis of the Upper-Air Temperature Condition for Weapon System Operating in the Korean Peninsula (한반도 지역의 고층대기에서 운용되는 무기체계를 위한 기온 조건 분석)

  • Kim, Hyun-myung;Kang, Dong-sik;Yang, Won-seok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.1
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    • pp.141-149
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    • 2019
  • This study analyzed upper-air temperatures in order to make temperature conditions for weapon system operating in Korean Peninsula. One of important tasks of environmental analysis is to set-up suitable temperature conditions for successful development of weapon system. Many weapon system developers are setting air temperature conditions based on the MIL-STD-810G. However, for weapons systems that are used only in the upper-air of the Korean Peninsula, the air temperature conditions recommended by MIL-STD-810G are often not suitable. To establish the air temperature conditions for upper-air in the Korean Peninsula, the method of Percentage of Occurrence should has be built up as method of temperature analysis. Upper-air climate data of the Korea Peninsulas over the past decade is also analyzed based on this method. The study suggest upper-air temperature conditions for weapons systems that are operated only in the Korean peninsula.

Spray combustion with high temperature air in a Gas Turbine Combustor (가스터빈 연소기내의 고온공기 분무연소 해석)

  • Jo, Sang-Pil;Kim, Ho-Young;Park, Sim-Soo
    • 한국연소학회:학술대회논문집
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    • 2004.06a
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    • pp.192-198
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    • 2004
  • A numerical study was conducted to determine the effects of high temperature air, including equivalent ratio on flow field, temperature, evaporation, and overall temperature distribution in gas turbine combustor. A sector model of a typical wall jet can combustor, featuring introduction of primary air and dilution air via wall jet, was used in calculations. Flow field and temperature distribution were analyzed. Operating conditions such as inlet temperature and overall equivalent ratio were varied from 373 to 1300 K, and from 0.3 to 0.6, respectively, while any other operating conditions were fixed. The RNG ${\kappa}-{\varepsilon}$ model and eddy breakup model were used for turbulence and combustion model respectively. It was found that the increase with the inlet air temperature, velocity in the combustor is accelerated and evaporation of liquid fuel is not affected in primary zone, high temperature inlet air enhances the evaporation and improves overall temperature distribution factor.

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Selection of Diffuser for Lower Temperature Air Distribution System (저온공조용 취출구의 선정)

  • Park, Sung-Kyu;Yoo, Ho-Joon;Choi, Myeong-Shin
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.484-492
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    • 2008
  • Air Discharge pattern and even temperature distribution is critical for a successful lower temperature air distribution system, which would supply lower temperature air than normal HAVC system. Selection of appropriate diffuser is the most critical element in completing lower temperature system.

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