Critical heat flux prediction for water boiling in vertical tubes of a steam generator

Payán-Rodríguez, Luis A.; Gallegos-Muñoz, A.; Porras-Loaiza, G.L.; Picón‐Núñez, Martín

doi:10.1016/j.ijthermalsci.2004.05.003

Cited by 18 publications

(5 citation statements)

References 3 publications

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“…Moreover, the fluid temperature increases with the load rise. In steam boilers with natural circulation, the vaporization process is by nucleate boiling to ensure continuous cooling of the heated wall of the tubes by water [33]. As long as this vaporization regime is maintained, the internal temperature of the wall remains higher than the fluid saturation temperature.…”

Section: Thermal-hydraulic Characteristicsmentioning

confidence: 99%

Modeling and simulation of a natural circulation water-tube steam boiler

et al. 2019

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In the present work, the overall behavior of a steam boiler is investigated using RELAP5/MOD3.2 system code at three different operating loads. Main thermal-hydraulic parameters are analyzed at steady-states corresponding to 60%, 100% and 110% of the boiler nominal load. RELAP5 system code is widely used in the design and safety analysis of nuclear reactor installations as well as for conventional facilities in recent years. The steam boiler studied herein is a water-tube natural circulation type used in a natural gas liquefaction complex for superheated steam production purposes. A complete model of the steam boiler has been developed for the RELAP5 code. This model, that is also suitable for transient simulation, has been used for the reconstruction of three steady-state tests in order to assess the steam boiler safety features during the operation. The model includes all parts that can eventually influence the safety of the steam boiler particularly the control and regulation system. A qualification process has been undertaken in the aim to verify the capability of the model to reproduce the main parameters of the steam boiler. This process revealed that RELAP5 system code results matches significantly the experimental data of the steam boiler. Finally, it should be mentioned that the results obtained so far are very encouraging for studying the general behavior of the steam boiler in transient operating conditions, as well as for evaluating its safety under hypothetical scenarios. This step will be undertaken in the near future and will allow the check of the code capability to simulate thermal-hydraulic phenomena occurring in the steam boiler during transient operation.

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Section: Thermal-hydraulic Characteristicsmentioning

confidence: 99%

Modeling and simulation of a natural circulation water-tube steam boiler

et al. 2019

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“…According to the actual geometry of the flow distribution plate, the secondary flow of inlet runs in at a distribution ratio of 4:1 at the hot and cold leg side respectively, resulting extreme unevenness of flow distribution characteristics at both ends. This alters the heat transfer process between vapor-liquid two-phase flow and boiling in the second side in such a evident way that it leads to phenomenon like dry and wet cycle, flow-induced vibration, film boiling etc [1], which seriously affects thermal-hydraulic characteristics in the steam generator. Therefore，it is of great significance for the safe operation of pressurized water reactor nuclear power plant to investigate thermal-hydraulic characteristics of steam generator with different flow distributions of the secondary inlet.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation about the Impacts of the Secondary Side Flow Distributions on the Flow and Heat Transfer in a Steam Generator

Yang

Sun

Wang

et al. 2012

2012 Asia-Pacific Power and Energy Engineering Conference

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Taken the steam generator of Daya Bay Nuclear Power Plant as the prototype, the "unit pipe" three-dimensional physical model of steam generator is established under the guidance of the similarity principle. Numerical simulation is implemented about the impacts of the secondary inlet flow distributions on the flow and heat transfer in a steam generator based on CFX by adopting flow-solid coupled heat transfer method and thermal phase change model. Compared with a inlet flow distribution ratio of 1:1, when the distribution ratio of the inlet secondary side flow is 4:1, the results show that a long secondary preheating section results, together with a low cross-section void fraction of the hot leg and a high value for the cold leg . The export mass fraction is consistent with the practical operating parameters of Daya Bay Nuclear Power Plant. Due to the fact that fluid velocity in the region of U bend for the secondary side flow is smaller, flow-induced vibration damage in U-bend tubes of the cold leg region is mitigated. Distributions of wall temperature are basically consistent with the experimental results; while tube wall has a low average temperature, especially in the hot leg. The numerical simulation method could provide technical support to accurately determine the flow distribution ratio of the secondary side for different types of steam generator.

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“…An important aspect of boiler design is related to the thermohydraulic behaviour of the furnace wall tubes. According to flue gas temperature distribution and the furnace wall heat flux distribution, the operating temperatures of evaporator heating surface can be accurately estimated to verify that tubes do not experience excessively high metal temperatures, which avoids resulting in tube failure due to overheating under practical operation [9]. Up to now, although the experiments of coal reburn have been conducted, most experiments were conducted in droptube furnaces and single burner furnaces [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Effect of coal-over-coal reburn on furnace temperature and heat flux distributions in 1MW tangentially fired furnace

Zhou

et al. 2010

International Journal of Thermal Sciences

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a b s t r a c tThe furnace temperature and heat flux distributions of 1 MW tangentially fired furnace were studied during coal-over-coal reburn, and the influences of the position of reburn nozzle and reburn fuel fraction on furnace temperature and heat flux distributions were investigated. Compared with the baseline, the flue gas temperature is 70-90 C lower in primary combustion and 130-150 C higher at furnace exit, and the variations of the flue gas temperature distributions along furnace height are slower. The temperature distribution along the width of furnace wall decreases with the increase of the relative furnace height. In the primary combustion zone and the reburn zone, the temperature and heat flux distributions of furnace wall are much non-uniform and asymmetric along the width of furnace wall, those of furnace wall in the burnout zone are relatively uniform, and the temperature non-uniformity coefficients of the primary combustion zone, the reburn zone and the burnout zone are 0.290, 0.100 and 0.031, respectively.

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Critical heat flux prediction for water boiling in vertical tubes of a steam generator

Cited by 18 publications

References 3 publications

Modeling and simulation of a natural circulation water-tube steam boiler

Modeling and simulation of a natural circulation water-tube steam boiler

Numerical Simulation about the Impacts of the Secondary Side Flow Distributions on the Flow and Heat Transfer in a Steam Generator

Effect of coal-over-coal reburn on furnace temperature and heat flux distributions in 1MW tangentially fired furnace

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