• 제목/요약/키워드: Cooling coil

검색결과 204건 처리시간 0.028초

열전소자를 이용한 액체 냉각기의 냉각열전달 특성 (Cooling characteristics of a Liquid cooler Using Thermoeletric Module)

  • 박민영;이근식
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2007년도 동계학술발표대회 논문집
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    • pp.197-202
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    • 2007
  • In this study, the cooling characteristics of a liquid cooler using thermoelectric module was experimentally investigated. The experiment was conducted for various inner structures of liquid cooler (4 cases), hot fluid flow rates (0.15-0.25 L/min), number of T.E module (2, 4, 6 set), and the cooling water flow rates (200-600 cc/min) for both parallel and counter flow types. Among the results, better cooling performance geometry was selected. And experiment was also carried out to examine further enhancement of cooling performance by inserting coils (pitches: 0.2, 3, 6 mm) into the hot-fluid channel. Present results showed that the short serpentine type(case2) indicated the best cooling performance. In the case of coil pitch of 3 mm, the best cooling performance was shown, more than 10% increase of the inlet and outlet temperature difference, compared with the case of the cooler without coil. Consequently, the inserted coil pitch should be properly selected to improve cooling performance.

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Analysis on electrical and thermal characteristics of MI-SS racetrack coil under conduction cooling and external magnetic field

  • Chae, Yoon Seok;Kim, Ji Hyung;Quach, Huu Luong;Lee, Sung Hoon;Kim, Ho Min
    • 한국초전도ㆍ저온공학회논문지
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    • 제23권4호
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    • pp.61-69
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    • 2021
  • This paper presents the analysis and experiment results on the electrical and thermal characteristics of metal insulation (MI) REBCO racetrack coil, which was wound with stainless steel (SS) tape between turn-to-turn layers, under rotating magnetic field and conduction cooling system. Although the field windings of superconducting rotating machine are designed to operate on a direct current, they may be subjected to external magnetic field due to the unsynchronized armature windings during electrical or mechanical load fluctuations. The field windings show the voltage and magnetic field fluctuations and the critical current reduction when they are exposed to an external magnetic field. Moreover, the cryogenic cooling conditions are also identified as the factors that affect the electrical and thermal characteristics of the HTS coil because the characteristic resistance changes according to the cryogenic cooling conditions. Therefore, it is necessary to investigate the effect of external magnetic field on the electrical and thermal characteristics of MI-SS racetrack coil for further development reliable HTS field windings of superconducting rotating machine. First, the major components of the experiment test (i.e., HTS racetrack coil construction, armature winding of 75 kW class induction motor, and conduction cooling system) were fabricated and assembled. Then, the MI racetrack coil was performed under liquid nitrogen bath and conduction cooling conditions to estimate the key parameters (i.e., critical current, time constant, and characteristic resistance) for the test coil in the steady state operation. Further, the test coil was charged to the target value under conduction cooling of 35 K then exposed to the rotating magnetic field, which was generated by three phrase armature windings of 75 kW class induction motor, to investigate the electrical and thermal characteristics during the transient state.

건물 공조용 냉수 코일의 열 설계 (Thermal Design of a Cooling Coil for Building Air Conditioning)

  • 김내현;변호원
    • 한국산학기술학회논문지
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    • 제16권10호
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    • pp.6445-6452
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    • 2015
  • 건물용 공기조화기의 냉수 코일은 작동조건에 따라 건표면, 습표면 또는 부분적인 습표면이 형성된다. 따라서 냉수코일을 적절히 설계하기 위해서는 건표면과 습표면, 그리고 부분적 습표면에 대한 열전달 해석이 필요하다. 본 연구에서는 미소체적에 대한 해석을 통하여 냉수코일의 성능을 계산하는 미소체적 모델을 제시하였다. 해석 모델의 예측치를 냉수코일 실험결과와 비교한 결과 미소 체적 모델은 공기측 전열량을 10.1% 이내에서 예측하고 공기측 압력손실을 11.1%, 현열비도 5.7%내로 예측하였다. 해석 모델을 활용하여 물측 회로의 변화가 냉수코일의 성능에 미치는 영향을 검토하였다.

75% 수소 BATCH 소둔시에서의 코일 온도변화에 관한 연구 (A study on coil temperature bariation in 75% hydrogen batch annealing furnace)

  • 전언찬;김순경
    • 한국정밀공학회지
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    • 제11권2호
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    • pp.173-181
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    • 1994
  • A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.

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인덕션 쿡탑 기구물 형상변경이 Heatsink 및 Coil 냉각성능에 미치는 영향에 대한 연구 (Study on the Cooling Performance of Heatsink for Induction Cooktop using Computational Fluid Dynamics)

  • 박동호;권명근;이동범;서응렬;박용종
    • 한국유체기계학회 논문집
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    • 제18권3호
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    • pp.33-37
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    • 2015
  • A numerical study on the IPM/Bridge Diode cooling and coil cooling has been performed. Results are presented as plots of thermal resistance, temperature drop and RPM-ratio. CFD analysis for conventional cooling system has been performed as a reference case. As the RPM-Ratio was increased, heatsink thermal resistance and coil temperature were decreased. IPM/Bridge Diode thermal resistance and temperature of the coil is tended to be trade-off. The temperature of coil closest to the AC-motor fan showed the most significant change in accordance with duct design. The temperature of coil located at the top of DC-motor fan showed the most significant variation as the cooling air passes the heatsink fin area.

600kJ급 SMES용 전도냉각시스템 열해석 (Thermal analysis of the conduction cooling system for HTS SMES system of 600 kJ class)

  • 홍용주;염한길;박성제;김효봉;고득용
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.1959-1963
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    • 2007
  • SMES systems need cryogenic cooling systems. Conduction cooling system has more effective, compact structure than cryogen. In general, 2 stage GM cryocoolers are used for conduction cooling of HTS SMES system. 1st stages of cryocoolers are used for the cooling of current leads and radiation shields, and 2nd stages of cryocoolers for HTS coil. For the effective conduction cooling of the HTS SMES system, the temperature difference between the cryocooler and HTS coil should be minimized. In this paper, a cryogenic conduction cooling system for HTS SMES is analyzed to evaluate the performance of the cooling system. The analysis is carried out for the steady state with the heat generation of the HTS coil and effects of the thermal contact resistance. The results show the effects of the heat generation and thermal contact resistance on the temperature distribution.

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KSTAR(Korea Superconducting Tokamak Advanced Research) 냉각 시스템에 대한 열해석 연구 (A Study on Thermo-Hydraulic Analysis for KSTAR(Korea Superconducting Tokamak Advanced Research) Cooling Line System)

  • 김홍원;하지수;김대순;이종석;최창호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.296-301
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    • 2003
  • A study on the engineering design and numerical thermo-hydraulic analysis for KSTAR TF coil structure cooling system has been conducted. The numerical analyses have been done to verify the engineering design of cooling using the commercial code, FLUENT and in-house code for calculating helium properties which varies with cooling tube's heat transfer. Through the engineering design process based on the steady heat balance concepts, the circular stainless steel tube with inner diameter of 4 mm for TF coil has been selected as cooling tube. From normal operation mode analysis results, total 28 cooling tubes were finally chosen. Also, three dimensional cool down analysis for TF coil with designed cooling tube was satisfied with next three design criteria. First is cooling work termination within a month, second is maximum temperature difference within 50 K in TF coil structure and third is exit helium pressure above 2 bar. Consequently, these cool down scenario results can afford to adopt as operating scenario data when KSTAR facilities operate.

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$\mu$ SMES 마그네트용 모델 코일의 ?치 특성 (Quench Characteristic of the Model Coil for a $\mu$ SMES Magnet)

  • 김해종;성기철;조전욱;김석환;이언용;권영길;류강식;류경우
    • 한국초전도ㆍ저온공학회논문지
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    • 제3권2호
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    • pp.5-9
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    • 2001
  • For the development of a small-sized superconducting magnetic energy storage($\mu$SMES) system we designed, fabricated and tested a model coil consisting of five coils with different features. e.g. winding tensions. bore diameters and materials. cooling channels. The results show that even in the highly pre-stressed small coil the quench currents of the coils are degraded to about 70% of their coils critical current. The quench currents of the coils with natrow cooling channels are two times as high as that of the coil without spacers. The test results also indicate that the usual training effect depends on the winding tensions of the coils according to materials of the bobbin.

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여러가지 열적 변수가 전폐형 유도전동기의 코일온도상승에 미치는 영향에 관한 연구 (The effects of various thermal parameters on coil temperature rise in TEFC induction motor)

  • 윤명근;하경표;이양수;고상근;한송엽
    • 대한기계학회논문집B
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    • 제21권4호
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    • pp.570-578
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    • 1997
  • At design stage of new motor or when taking remedial action of old motor, a lot of information can be obtained from thermal parameters analysis. This study focused on the temperature rise of TEFC induction motor with respect to various thermal parameters. Frame heat transfer had the most important effect on coil temperature rise. But those of air gap and rotor fan had no effect. This fact shows fan action is more important than fin action in the case of rotor fan. Coil temperature can be more decreased by cooling near the heat sources than any other parts from the results of thermal conductivity and loss tests. Variation of cooling air flow rate and motor volume effects on coil temperature were also tested. These tests suggest that improvement of cooling fan performance is important in reducing the coil temperature rise. Thermal equivalent program was verified by comparison of some experimental results.

HNx 분위기가스중에서 BAF소둔시 코일의 온도변화에 관한 연구 (A Study on Temperature Variation of Coil on BAF Annealing in HNx Atmospheric Gas)

  • 전언찬;김순경
    • 대한기계학회논문집
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    • 제18권5호
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    • pp.1227-1234
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    • 1994
  • A cold spot temperature control system for the batch annealing furnace has been established in order to reduce energy consumption which is essential to improve productivity and stabilize the properties of products. A relationship between annealing cycle time and gas flow rate is developed and also for the variation of coil cold spot temperature with time during heating, and actual temperature measurements at mid-width of each coil during soaking. The results of the temperature variation effect on the cold rolled steel sheet batch annealing are as follows. (1) Cooling rate increasing gradually with increasing atmospheric gas flow, but heating rate is hardly increasing without atmospheric gas component change. (2) In case of short time heating, the slowest heating part is the center of B coil and in case of ling time heating, the low temperature point moves from the center of coil to inside coil. (3) The outside of top coil is the highest temperature point under heating, which becomes the lowest temperature point under cooling. (4) Soaking time determination depends on the input coil width, and soaking time for quality homogenization of 1214 mm width coil must be 2 hours longer than that of 914 mm width coil.