• Title/Summary/Keyword: Temperature calculation

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Thermal Analysis of High Density Permanent Magnet Synchronous Motor Based on Multi Physical Domain Coupling Simulation

  • Chen, ShiJun;Zhang, Qi;He, Biao;Huang, SuRong;Hui, Dou-Dou
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.91-99
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    • 2017
  • In order to meet the thermal performance analysis accuracy requirements of high density permanent magnet synchronous motor (PMSM), a method of multi physical domain coupling thermal analysis based on control circuit, electromagnetic and thermal is presented. The circuit, electromagnetic, fluid, temperature and other physical domain are integrated and the temperature rise calculation method that considers the harmonic loss on the frequency conversion control as well as the loss non-uniformly distributed and directly mapped to the temperature field is closer to the actual situation. The key is to obtain the motor parameters, the realization of the vector control circuit and the accurate calculation and mapping of the loss. Taking a 48 slots 8 poles high density PMSM as an example, the temperature rise distribution of the key components is simulated, and the experimental platform is built. The temperature of the key components of the prototype machine is tested, which is in agreement with the simulation results. The validity and accuracy of the multi physical domain coupling thermal analysis method are verified.

Development and verification of PWR core transient coupling calculation software

  • Li, Zhigang;An, Ping;Zhao, Wenbo;Liu, Wei;He, Tao;Lu, Wei;Li, Qing
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3653-3664
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    • 2021
  • In PWR three-dimensional transient coupling calculation software CORCA-K, the nodal Green's function method and diagonal implicit Runge Kutta method are used to solve the spatiotemporal neutron dynamic diffusion equation, and the single-phase closed channel model and one-dimensional cylindrical heat conduction transient model are used to calculate the coolant temperature and fuel temperature. The LMW, NEACRP and PWR MOX/UO2 benchmarks and FangJiaShan (FJS) nuclear power plant (NPP) transient control rod move cases are used to verify the CORCA-K. The effects of burnup, fuel effective temperature and ejection rate on the control rod ejection process of PWR are analyzed. The conclusions are as follows: (1) core relative power and fuel Doppler temperature are in good agreement with the results of benchmark and ADPRES, and the deviation between with the reference results is within 3.0% in LMW and NEACRP benchmarks; 2) the variation trend of FJS NPP core transient parameters is consistent with the results of SMART and ADPRES. And the core relative power is in better agreement with the SMART when weighting coefficient is 0.7. Compared with SMART, the maximum deviation is -5.08% in the rod ejection condition and while -5.09% in the control rod complex movement condition.

A Study for Estimation of the Surface Temperature Rise Using the FVM and Semi-Infinite Solid Analysis (FVM과 반무한체 해석을 이용한 표면온도예측에 관한 연구)

  • 이상돈;김태완;조용주
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.260-266
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    • 2001
  • The surface temperature at the interface of bodies in a sliding contact is one of the most important factors influencing the behavior of machine components. So the calculation of the surface temperature at a sliding contact interface has long been an interesting and important subject for tribologist. Several methods for calculating surface temperature have been devised. Several numerical methods have been used to predict the temperature rise of sliding surface. but those need much time to calculate. In this study to reduce the calculation time the hybrid method using both semi-infinite solid analysis and FVM was used. It is founded that the computing time of hybrid method was shorter than that of FVM.

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Simulation of Temperature Behavior in Hydrogen Tank During Refueling Using Cubic Equations of State (3차 상태방정식을 이용한 수소 충전 온도 거동 모사)

  • PARK, BYUNG HEUNG
    • Journal of Hydrogen and New Energy
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    • v.30 no.5
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    • pp.385-394
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    • 2019
  • The analysis of temperature behavior of a hydrogen tank during refueling is of significance to clarify the safety of the compressed hydrogen storage in vehicles since the temperature at a tank rises with inflow of hydrogen. A mass balance and an energy balance were combined to obtain analytical model for temperature change during the hydrogen refueling. The equation was coupled to Peng-Robinson-Gasem (PRG) equation of state (EOS) for hydrogen. The PRG EOS was adopted after comparison with other four different cubic EOSs. A parameter of the model was determined to fit data from experiments of various inlet flow rates and temperatures. The temperature and pressure change with refueling time were obtained by the developed model. The calculation results revealed that the extent of precooling was more effective than the flow rate control.

Temperature control of a batch PS polymerization reactor using on-line two-step method (온라인 2단계 방법을 이용한 회분식 PS 중합반응기의 온도제어)

  • 이병모;노형준;이현구
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.305-308
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    • 1997
  • The on-line calculation method is developed to obtain the temperature trajectory that brings the reactants to the desired state in batch styrene polymerization reactor. The temperature trajectory is obtained by applying the moments of the polymer concentration to the 2-step calculation method. The computer simulation is also carried out to verify the superiority of the on-line method to the off-line one. When a temperature disturbance of constant size is introduced, the off-line results shows considerable deviation from the target degree of polymerization. The on-line strategy set up a new trajectory to reach the desired state by using the current state of the reactor. Therefore, the on-line strategy deals with the changes of the system more adequately than the off-line strategy.

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A study on the Evaluation of Heat Transfer Coefficient by Optimization Algorithm (최적화 기법을 활용한 열전달계수의 측정)

  • Kim, J.T.;Lim, C.H.;Choi, J.K.
    • Transactions of Materials Processing
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    • v.15 no.9 s.90
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    • pp.679-685
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    • 2006
  • New method for evaluation of heat transfer coefficient is proposed. In general, many researchers have been studied about inverse problem in order to calculate the heat transfer coefficient on three-dimensional heat conduction problem. But they can get the time-dependent heat transfer coefficient only through inverse problem. In order to acquire temperature-dependent heat transfer coefficient, it requires much time for numerous repetitive calculation and inconvenient manual modification. In order to solve these problems, we are using the SQP(Sequential Quadratic Programming) as an optimization algorithm. When the temperature history is given by experiment, the optimization algorithm can evaluate the temperature-dependent heat transfer coefficient with automatic repetitive calculation until difference between calculated temperature history and experimental ones is minimized. Finally, temperature-dependent heat transfer coefficient evaluated by developed program can used on various heat transfer problem.

CFD Simulations of the Ground Surface Temperature and Air Temperature, Air flow Coupled with Solar Radiation (태양복사열에 따른 지표면 온도와 열, 기류 환경 시뮬레이션 연구)

  • Lee, JuHee;Kim, JaeGwon;Yoon, JaeOck
    • KIEAE Journal
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    • v.14 no.3
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    • pp.65-70
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    • 2014
  • The thermal environment in a small city rapidly deteriorates due to the urbanization and overpopulation. It is important to understand and predict the thermal environment in a city area. The thermal environment is highly affected by the solar radiation and temperature distributions changing over time periodically. To predict the thermal environment precisely, the solar radiation calculation including radiation strength, incidence angle, and thermal radiation between building surface and ground should be considered. In this study, the computational domain includes various artificial structures such as building, ground, asphalt, brick and grass. To consider the solar radiation, the unsteady state numerical calculation is performed from sun rise to mid-day (2:00pm). The numerical methods consist of solar load and one dimensional heat conduction through the boundaries to reduce the computational load and improve the flexibility of the calculation.

Effects of Condensation Heat Transfer Model in Calculation for KNGR Containment Pressure and Temperature Response

  • Eoh, Jae-Hyuk;Park, Shane;Jeun, Gyoo-Dong;Kim, Moo-Hwan
    • Nuclear Engineering and Technology
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    • v.33 no.2
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    • pp.241-253
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    • 2001
  • Under severe accidents, the pressure and temperature response has an important role for the integrity of a nuclear power plant containment. The history of the pressure and temperature is characterized by the amount and state of steam/air mixture in a containment. Recently, the heat transfer rate to the structure surface is supposed to be increased by the wavy interface formed on condensate film. However, in the calculation by using CONTAIN code, the condensation heat transfer on a containment wall is calculated by assuming the smooth interface and has a tendency to be underestimated for safety. In order to obtain the best- estimate heat transfer calculation, we investigated the condensation heat transfer model in CONTAIN 1.2 code and adopted the new forced convection correlation which is considering wavy interface. By using the film tracking model in CONTAIN 1.2 code, the condensate film is treated to consider the effect of wavy interface. And also, it was carried out to investigate the effect of the different cell modelings - 5-cell and 10-cell modeling - for KNGR(Korean Next Generation Reactor) containment phenomena during a severe accident. The effect of wavy interface on condensate film appears to cause the decrease of peak temperature and pressure response . In order to obtain more adequate results, the proper cell modeling was required to consider the proper flow of steam/air mixture.

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Calculation of Heat Transfer Coefficients by Steady State Inverse Heat Conduction (정상상태의 열전달계수 예측을 위한 최적화기법의 열전도 역문제에 관한 연구)

  • 조종래;배원병;이부윤
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.5
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    • pp.549-556
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    • 1997
  • The inverse heat conduction problems is the calculation of surface heat transfer coefficients by utilizing measured temperature. The numerical technique of finite element analysis and optimizition is introduced to calculate temperatures and heat transfer coefficients. The calculated heat transfer coefficients and temperature distribution are good agreement with the results of direct analysis. The inverse method has been applied to the control valve of nuclear power plant.

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The calculation and Measurement Methods for G/T of the Telemetry Small Aperture Antenna (원격자료수신장비 소형반사판 안테나 G/T 예측 및 측정)

  • Kim, Chun-Won;An, Na-Gyun;Kim, Dong-Hyun;Cho, Byung-Lok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.9
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    • pp.657-662
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    • 2022
  • In this paper, the calculation using simulation and two measurement methods for G/T of the telemetry are analyzed. Antenna gain and noise temperature are calculated by using ICARA and Antenna Noise Temperature Calculator. System G/T were calculated by using Antenna gain/noise temperature, LNA gain/noise temperature, cable loss. The first G/T measurement method is Y-factor measurement method, which is to calculate G/T by comparing LNA noise temperature and a signal level difference when an antenna and a 50ohm termination are respectively connected to an LNA input terminal Second method is Solar calibration measurement method that is to calculate G/T by comparing noise level difference when looking at the sun and lowest level point. Finally, the accuracy was reviewed by comparing the G/T calculation results with the two measurement methods, and the optimal measurement method according to antenna performance and operating environment was presented.