• Title/Summary/Keyword: Thermal Control

Search Result 3,086, Processing Time 0.033 seconds

Thermal Crack Control of LNG Tank Roof (LNG 탱크 Roof의 온도균열 제어)

  • 김태홍;하재담;유재상;이종열;권영호
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2002.10a
    • /
    • pp.421-424
    • /
    • 2002
  • Concrete roof in In-Chon LNG tank #15~18 is a very important structure. Precise control of quality is needed. This roof has 0.6~1.5m thickness, 36.23m radius, and, 12.7m height. So in this structure thermal crack caused by hydration heat should be controled. In this project belite cement plus LSP concrete is used. As a result of ambient temperature rising test and thermal analysis using FEM, this belite cement plus LSP concrete is expected to control the thermal crack well.

  • PDF

Robust-Optimal Vibration Control of a Beam Using Thermal Stress (열응력을 이용한 보의 강인-최적 진동제어)

  • 권태철;이우식;김진걸
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1993.10a
    • /
    • pp.232-239
    • /
    • 1993
  • The vibration damping of structure is increased by thermal actuator. The thermal actuator causes thermal stress across the section of structure. The several kinds of control theories are proposed and the proposed control theories are successful in increasing vibration damping. This scheme can be effectively applied to large space structure [LSS] having very low natural frequencies.

  • PDF

Heliostat Control System (Heliostat 제어시스템)

  • Park, Young-Chil
    • Journal of the Korean Solar Energy Society
    • /
    • v.29 no.1
    • /
    • pp.50-57
    • /
    • 2009
  • Heliostat in the tower type solar thermal power plant is a mirror system tracking the sun's movement to collect the solar energy and it is the most important subsystem determining the efficiency of solar thermal power plant. Thus a good performance of it, which is mostly the accurate sun tracking performance under the various hazardous operating condition, is required. Heliostat control system is a system to manage the heliostat sun tracking movement and other operations. It also communicates with the master controller through the heliostat filed control system to receive and send the informations required to operate the heliostat as a part of the solar thermal power plant. This study presents a heliostat control system designed and developed for the 1MW solar thermal power plant. We first define the functionality of heliostat control system. Then sun tracking controller as well as the sun tracking algorithm satisfying the required functionality have been developed. We tested the developed heliostat control system and it showed a good performance in regulation of heliostat motion and communication.

Data Analysis of KOMPSAT Thermal Test in Simulated On-orbit Environment

  • Kim, Jeong-Soo;Chang, Young-Keun
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.1 no.2
    • /
    • pp.30-42
    • /
    • 2000
  • On-orbit thermal environment test of KOMPSAT was performed in early 1999. An analysis of the test data are addressed in this paper. For the thermal-environmental simulation of spacecraft bus, an artificial heating through the radiator zones and onto some critical heat-dissipating electronic boxes was made by Absorbed-heat Flux Method. Test data obtained in terms of temperature history were reduced into flight heater duty cycles and converted into the total electrical power required for spacecraft thermal control. Verification result of flight heaters dedicated to the bus thermal control is presented. Additionally, an exhaustive heating-control process for maintaining the spacecraft thermally safe and for realistic simulation of the orbital-thermal environment during the test are graphically shown. Qualitative suggestions to post-test model correlation are given in consequency of the analysis.

  • PDF

The Influence of Thermal Head and Feet Support on Early Stage Weight Gain in Premature Neonates (미숙아의 머리 및 발 보온이 출생초기 체중에 미치는 영향)

  • Paik Seung Nam;Hong Hye sung;Sung Mi Hae;Cho Kyoul Ja;Yhee Hyun Joo
    • Child Health Nursing Research
    • /
    • v.6 no.3
    • /
    • pp.397-410
    • /
    • 2000
  • This is a nonequivalent control group pretest- posttest design in quasi experimental basis to assess how the thermal head and feet support influences on early stage weight gain in premature neonates. The clients were selected among the premature infants with the weight under 2000gms and with the gestational period under 37 weeks, admitted over 15 days in K university hospital, Seoul. The control group of 29 were selected from January 1998 to August 1998, who were without head and feet thermal support, and the experimental group of 30 were selected from September 1998 to May 1999, who were with the two thermal interventions. The results of the study follow, 1.The experimental group with thermal interventions showed more weight gain than the control group without thermal interven- tions, which was statistically significant between the two groups. 2.The physiological weight loss after birth showed less in the experimental group than in the control group. 3.The recovery of the birth weight after the physiologic weight loss showed no statistical difference between the experimental group and the control group. Consequently, the thermal head and feet supportive nursing intervention could be applied as a nursing intervention program to help the premature neonates' development. With the results above we should like to suggest the following: 1) A continuous application in the practice of our thermal supportive intervention for the premature neonates, a development of the content through evaluation, and a comparision of the results through a long time study. 2) A neccessity of deveopment of various study and cross comparision. 3) A neccessity of multi-angular study on the premature infants' characteristics influencing the thermal therapy and the study of the individual differences of the clients.

  • PDF

Thermal Vacuum Test of the Phase Change Material Thermal Control Unit Loaded on the Satellite Flight Model and Thermal Model Correlation with Test Results (위성에 탑재된 상변화물질 열제어장치 비행모델의 열진공시험 및 이를 통한 열해석 모델 보정)

  • Cho, Yeon;Kim, Taig Young;Seo, Joung-Ki;Jang, Tae Seong;Park, Hong-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.50 no.10
    • /
    • pp.729-737
    • /
    • 2022
  • Melting and icing process of the PCMTCU(Phase Change Material Thermal Control Unit) installed on the NEXTSat-2, which is scheduled to be launched in the second half, was investigated through the results of satellite-level TVT(Thermal Vacuum Test). As a result of the test, it was confirmed that the latent heat of PCM contributes to the temperature stabilization of the heating components. The thermal model for numerical analysis of the PCMTCU was correlated to acquire a reasonable degree of accuracy using the collected temperature measurements during TVT. The periodic temperature variation of the PCMTCU in normal on-orbit operation was predicted with the correlated thermal model, and the quantitative contribution of the PCM on the thermal energy management was evaluated with the liquid fraction. It will receive flight telemetry from the NEXTSat-2 after the launch, and complete the space verification of the PCMTCU.

A Study on Turbine Control and Turbine Bypass Control during Startup of Thermal Power Plants (화력발전소 기동시 터빈 바이패스 시스템과 터빈 제어에 관한 고찰)

  • Choi, In-Kyu;Park, Doo-Yong
    • Proceedings of the KIEE Conference
    • /
    • 2009.07a
    • /
    • pp.1664_1665
    • /
    • 2009
  • Many years ago, most of thermal power plants built in this country were of subcritical pressure, of medium or small size, of constant pressure operations and of drum type steam generators with circulation type boilers. But, nowadays almost all of them were of high efficiency, of supercritical pressure, of big capacity, of sliding pressure operations, and of once through type steam generator. It has such advantage as the reduction of startup duration, but it control system and operation method are very complicated. It has a big difference in operation method of turbine and boiler. The feedforward control needs to be introduced to prevent such problems as thermal shock during the transit from normal operation into bypass operation. This paper introduces the turbine control and turbine bypass control during startup of thermal power plants.

  • PDF

Steam Temperature Control of Attemperator in Thermal Power Plant (화력발전소에서 과열저감기의 증기온도제어)

  • Shin, Hwi-Beom
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.25 no.7
    • /
    • pp.40-48
    • /
    • 2011
  • An attemperator is a part of the 4-stage superheater in the boiler system of the thermal power plant. The attemperator receives the over-heated steam and makes the steam with proper temperature by adjusting the control valve of the cold steam. In this paper, the attemperator is modeled considering physical point of view and the linearized model is derived for the control purpose. To overcome the integral windup phenomenon due to the opening limitation of the control valve, an anti-windup PI controller is proposed to the attemperator and compared with the PI controller operated in the thermal power plant in view of control performance.

The improvement of control strategy in thermal power plant turbine system by nonlinear analysis (비선형성 해석에 의한 화력발전소 터어빈 제어계통에 관한 연구)

  • ;;Hwang, Jae-Ho;Seo, Jin-Hun
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1989.10a
    • /
    • pp.567-571
    • /
    • 1989
  • This paper describes the improvement of thermal power plant turbine control system by analyzing nonlinear characteristics. The turbine control depends on the frequency variation and boiler condition. The nonlinearity of turbine control is the result of governor/valve properties, steam condition and boiler thermal unbalance. Nonlinear analysis is divided into two; main steam valve position - turbine output anal governor response. Of course, every analysis must be done on considering plant operating condition. In this paper, after analyzing turbine control nonlinearity by numerical method and actual results, the sensitive operating load which corresponds to frequency is proposed, on guarranteed boiler stability. This idea is implemented at Pyung Tack thermal power plant, and the practical results are showed.

  • PDF

Implementation of the Thermal Control System using RVEGA-Fuzzy Control Technique (RVEGA-퍼지 제어 기법을 이용한 온도 제어 시스템의 구현)

  • 김정수;정종원;박두환;지석준;이준탁
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • 2001.05a
    • /
    • pp.238-242
    • /
    • 2001
  • In this paper, we proposed an optimal identification method of the membership functions and the numbers of fuzzy rule base for the stabilization controller of the Thermal process control system by RVEGA. Although fuzzy logic controllers and expert systems have been successfully applied in many complex industrial process, they must rely on experts knowledges. So it is difficult in determination of the linguistic state space, definition of the membership functions of each linguistic term and the derivation of the control rules. To verify the validity of this RVEGA-based fuzzy controller, Thermal process control system, with strong nonlinear dynamics, was selected for application of this algorithm and compare with PI controller, and the empirically improved fuzzy controller.

  • PDF