• Title/Summary/Keyword: Thermal Condition

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A Study on Validation of Condition Monitering Method of Accelerated Thermal Aging CSPE (가속열화 된 CSPE 상태감시법의 유효성 연구)

  • Shin, Yong-Deok;Goo, Cheol-Soo;Kim, In-Yong;Lee, Jung-Hoon
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1447-1448
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    • 2011
  • The CSPE cables are used for three years in nuclear power plant. The accelerated thermal aging of chloro sulfonate polyethylene(CSPE) jacket of test cables were carried out for the period equal to 10, 20 and 30 years in air at 90 and $100^{\circ}C$, respectively. The electrical volume resistivity, density, XPS, FE-SEM, EDS and XRF of the accelerated thermal aging of CSPE were measured. The validation of condition monitering method of accelerated thermal aging CSPE was estimated by them. The best validation of condition monitoring method of accelerated aging CSPE is electrical volume resistivity because change thermal of the specimen showed distinction.

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A Study on Thermal Stress in T/G Wall of Containment Building (격납건물 텐던갤러리 벽체의 온도응력에 대한 연구)

  • 김진근;양은익;박영진;송영철;방기성
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.193-198
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    • 1998
  • In this study, the change of concrete temperature, strain and thermal stress were measured by using the embedded type concrete gauges in tendon gallery wall of containment building. A finite element analysis was performed to clarify the thermal behavior of concrete. The analytic and test results were investigated to improve the validity of analytic method. According to the test results, concrete temperature, strain and thermal stress were strongly affected by measuring point and environment condition of member. And the thermal stress was developed in the member which was not demoulded at early ages. This is caused by the change of internal temperature and restrained condition. A finite element effectively interpreted the test results by estimating the concrete properties and the site condition.

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Establishment of Optimum Floor Surface Temperature Floor in Ondol Heating System (온수온돌 난방시 바닥면의 중성온도 설정에 관한 연구)

  • 공성훈
    • Journal of the Korean housing association
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    • v.6 no.2
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    • pp.51-55
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    • 1995
  • This study presents a real neutral floor surface temperature in floor panel heating system(Ondol). The Ondol heating system can keep the constant temperature. However, the actual temperature when a person sits on a floor can be different from the surface temparature of a floor it self. The contents of this study are as follows : 1) measuring the spatial distributions of thermal conditions 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) estimating the neutral floor surface temperatures by measuring floor surface temperatures.

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A Study on the Analysis of the Thermal Stress in Process of STS 304 TIG Welding (STS 304 TIG 용접시 발생하는 열응력 해석에 관한 연구)

  • 고준빈;최원두;이영호
    • Journal of Welding and Joining
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    • v.19 no.6
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    • pp.658-663
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    • 2001
  • Residual stress caused in the weldments with high restraint force are often during welding observed in the weldments of large size nozzles or radial tanks. The reason is that quantitative analysis about thermal stresses during welding is lack for this weldments. To verify FEM theory, the temperature was measured with thermocouple in a real time in this paper. Also analysis of the thermal stress for welding condition is performed by ABAQUS program package on various welding condition in STS butt welding.

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Thermal Design for Satellite Propulsion System by Thermal Analysis (열해석에 의한 인공위성 추진시스템 열설계)

  • Han, Cho-Young;Kim, Jeong-Soo;Rhee, Seung-Wu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.117-124
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    • 2003
  • Thermal design fur satellite propulsion system has been performed. Overall design requirements and the constitution for propulsion system is described. To meet the thermal design requirements, both a primary and a redundant heater circuit, each with two thermostats placed in series, will protect each hydrazine-wetted components, even if one heater circuit fails to operate. Heater power is turned off if any one of these thermostats is opened at its higher setpoint. Thus, even if one thermostat is failed closed, the second thermostat will turn off the heater. All such components shall be insulated with MLI. Propulsion heater sizing based on the constant worst cold case condition is conducted through thermal analysis. All heaters selected fur propulsion components operate to prevent propellant freezing satisfying the thermal requirements for the propulsion subsystem over the worst case average voltage, i.e. 25 volts.

A Study on the Thermal Experiment for the Compensation of Thermal Deformation in Machine Tools (공작기계 열변형 보정을 위한 발열실험 방법에 관한 연구)

  • 윤인준;김형식;고태조;김희술
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.1
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    • pp.1-8
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    • 2004
  • Thermal distortion is a critical issue in machine tools, especially in high speed machining. This is the reason why recent machine tools have thermal compensation function. To compensate thermal distortion, it is necessary to make a model that has some relationship between temperature and deformation. Various experimental methods ye widely been used in thermal test: constant spindle speed, unit step speed increase, random spindle speed, etc. This paper focuses on which type of spindle operation condition is good for thermal experiment. Also, experimental data is modeled using multiple linear regression models and compared each other to select a method. Consequently, it turned out at e condition of 75% constant of maximum spindle speed is good enough to generate temperature and distortion data.

PRELAUNCH THERMAL ANALYSIS OF KSLV-I PAYLOAD FAIRING

  • Choi Sang-Ho;Kim Seong-Lyong;Kim Insun
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.356-359
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    • 2004
  • Prelaunch thermal analysis of the KSLV (Korea Space Launch Vehicle)-I PLF (Payload Fairing) was performed to predict maximum/minimum liftoff temperatures and to evaluate of air conditioning performance. Prelaunch thermal analysis includes internal air conditioning effect, external convective heating/cooling, radiation exchange with the ground and sky, radiation between spacecraft and PLF, and solar radiation incident on PLF. Analysis was performed at two extreme conditions, hot day condition and cold day condition. The results showed that the maximum liftoff temperature was $53^{\circ}C$ and the minimum liftoff temperature was $-3.8^{\circ}C$. It was also found that conditioned air supplying, in $20{\pm}2^{\circ}C\;and\;1200\;m^3/hr$, is sufficient to keep the internal air in required temperature range.

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Numerical Study on the Effect of Exhaust Flow Pattern under Real Running Condition on the Performance and Reliability of Closed-Coupled Catalyst (실 운전조건에서의 배기유동패턴이 근접장착 촉매변환기의 성능 및 신뢰성에 미치는 영향에 관한 수치적 연구)

  • 정수진;김우승
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.54-61
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    • 2004
  • The engine-out flow is highly transient and hot, and may place tremendous thermal and inertial loads on a closed-coupled catalyst. Therefore, time-dependent and detailed flow and thermal field simulation may be crucial. The aim of this study is to develop combined chemical reaction and multi-dimensional fluid dynamic mathematical model and to study the effect of unsteady pulsating thermal and flow characteristics on thermal reliability of closed-coupled catalyst. The effect of cell density on the conversion performance under real running condition is also investigated. Unlike previous studies, the present study focuses on coupling between the problems of pulsating flow pattern and catalyst thermal response and conversion efficiency. The results are expressed in terms of temporal evolution of flow, pollutant and temperature distribution as well as transient characteristics of conversion efficiency. Fundamental understanding of the flow and thermal phenomena of closed-coupled catalyst under real running condition is presented. It is shown that instants of significantly low values of flow uniformity and conversion efficiency exist during exhaust blowdown and the temporal varaition of flow uniformity is very similar in pattern to one of conversion efficiency. It is also found that the location of hot spot in monolith is directly affected by transient flow pattern in closed-coupled catalyst.

Evaluation of Thermal Dmage for Railway Weel (차륜에 대한 열손상 평가)

  • Kwon, Seok-Jin;Seo, Jung-Won;Lee, Dong-Hyong;Kim, Young-Kyu;Kim, Jae-Chul
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.966-970
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    • 2011
  • The thermo-mechanical interaction between brake block and wheel tread during braking has been found to cause thermal crack on the wheel tread. Due to thermal expansion of the rim material, the thermal cracks will protrude from the wheel tread and be more exposed to wear during the wheel/block contact than the rest of the tread surface. The wheel rim is in residual compression stress when is new. After service running, the region in the tread has reversed to tension. This condition can lead to the formation and growth of thermal cracks in the rim which can ultimately lead to premature failure of wheel. In the present paper, the thermal cracks of railway wheel, one of severe damages on the wheel tread, were evaluated to understand the safety of railway wheel in running condition. The residual stresses for damaged wheel which are applied to tread brake are investigated. Mainly X-ray diffusion method is used. Under the condition of concurrent loading of continuous rolling contact with rails and cyclic frictional heat from brake blocks, the reduction of residual stress is found to correlate well with the thermal crack initiation.

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Faultproof Design in Space for Monopropellant Rocket Engine Assembly (단일추진제 로켓 엔진 어셈블리를 위한 우주 공간에서의 과실 방지 설계)

  • Han, Cho-Young;Kim, Jeong-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.10
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    • pp.1377-1384
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    • 2003
  • An analysis has been performed for active thermal control of the KOMPSAT monopropellant rocket engine assembly, i.e., dual thruster module(DTM). The main efforts of this work have been directed at determining proper heater sizes for propellant valves and catalyst beds necessary to maintain their temperatures within specified temperature ranges under KOMPSAT environment and operational conditions. The TAS incorporated with TRASYS thermal radiation analyzer was used to establish a complete heat transfer model which allows to predict the DTM temperature as a function of time. The thermal analysis has been performed in transient mode to verify the appropriate power for catalyst bed heaters necessary to increase catalyst bed temperature to the required value within a specified period of time. Similar analysis has been executed to validate the heater power for the thermostatically controlled primary and redundant heater circuits used to prevent hydrazine freezing, i.e., single fault. Moreover the effect of the radiative property of thermal control coating of heat shield was examined. Thruster firing condition was also simulated for the heat soakback condition. As a consequence, all thermal analysis results for DTM satisfactorily met the thermal requirements for the KOMPSAT DTM under the worst case average voltage, i.e. 25 volt.