Prediction of the Departure from Nucleate Boiling with CFD Code

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F46356088%3A_____%2F18%3AN0000047" target="_blank" >RIV/46356088:_____/18:N0000047 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Prediction of the Departure from Nucleate Boiling with CFD Code

Popis výsledku v původním jazyce

This paper presents an attempt to use multiphase CFD code for the prediction of the Departure from Nucleate Boiling (DNB) type of Critical Heat Flux (CHF). Numerical simulations of DNB in boiling flow in vertical tube were performed with the Ansys CFX 18 code [1-2]. This code can simulate multiphase flow by solving three balance equations for each phase. Boiling on the heated wall was simulated with Kurul and Podowski model. A set of mathematical models of physical phenomena in boiling bubbly flow was selected and successfully tested on the DEBORA experiments [3-4] with subcooled boiling flow. The same set of models was then used in the simulations of DNB cases. Simulated cases were based on data from the 2006 CHF look-up table by D. C. Groeneveld [5]. It was found out that the local criterion for DNB prediction can be derived from the following parameters calculated with the CFD code on the wall: void fraction, wall superheating and wall shear stress. The proposed method of DNB detection was so far tested on 16 MPa pressure level on more than 60 cases covering a large range of parameters (mass flux 1000 - 8000 kg/m2/s and exit equilibrium quality -0.5 – 0) and it worked with +-10% accuracy in all solved cases apart from two cases with low mass flux where converged solution was not obtained. Presented work was carried out within the Technology Agency of the Czech Republic (TA ČR) project TH02020360 „Modeling of the critical heat flux with computational fluid dynamics codes“. Presented at 28th Symposium of AER on VVER Reactor Physics and Reactor Safety, Olomouc, Czech Republic, October 8-12, 2018.

Název v anglickém jazyce

Prediction of the Departure from Nucleate Boiling with CFD Code

Popis výsledku anglicky

This paper presents an attempt to use multiphase CFD code for the prediction of the Departure from Nucleate Boiling (DNB) type of Critical Heat Flux (CHF). Numerical simulations of DNB in boiling flow in vertical tube were performed with the Ansys CFX 18 code [1-2]. This code can simulate multiphase flow by solving three balance equations for each phase. Boiling on the heated wall was simulated with Kurul and Podowski model. A set of mathematical models of physical phenomena in boiling bubbly flow was selected and successfully tested on the DEBORA experiments [3-4] with subcooled boiling flow. The same set of models was then used in the simulations of DNB cases. Simulated cases were based on data from the 2006 CHF look-up table by D. C. Groeneveld [5]. It was found out that the local criterion for DNB prediction can be derived from the following parameters calculated with the CFD code on the wall: void fraction, wall superheating and wall shear stress. The proposed method of DNB detection was so far tested on 16 MPa pressure level on more than 60 cases covering a large range of parameters (mass flux 1000 - 8000 kg/m2/s and exit equilibrium quality -0.5 – 0) and it worked with +-10% accuracy in all solved cases apart from two cases with low mass flux where converged solution was not obtained. Presented work was carried out within the Technology Agency of the Czech Republic (TA ČR) project TH02020360 „Modeling of the critical heat flux with computational fluid dynamics codes“. Presented at 28th Symposium of AER on VVER Reactor Physics and Reactor Safety, Olomouc, Czech Republic, October 8-12, 2018.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

20305 - Nuclear related engineering; (nuclear physics to be 1.3);

Projekt

<a href="/cs/project/TH02020360" target="_blank" >TH02020360: Modelování vzniku CHF - krize varu pomocí výpočetních programů typu CFD</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů