Grid studies for the simulation of resolved structures in an Eulerian two-fluid framework
| Autor: | Eckhard Krepper, Friederike Gauss, Dirk Lucas |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Nuclear and High Energy Physics
Engineering Bubble multiphase flow Flow (psychology) Context (language use) 02 engineering and technology grid study 01 natural sciences Volume of Fluid method 010305 fluids & plasmas law.invention terminal rise velocity Physics::Fluid Dynamics symbols.namesake 020401 chemical engineering law Eulerian two-fluid method 0103 physical sciences Range (statistics) General Materials Science Limit (mathematics) 0204 chemical engineering Safety Risk Reliability and Quality Waste Management and Disposal business.industry Mechanical Engineering single rising bubble Eulerian path Structural engineering Mechanics Nuclear reactor Grid Nuclear Energy and Engineering symbols business |
| Zdroj: | Nuclear Engineering and Design 305(2016), 371-377 |
| Popis: | The influence of the grid size on the rise velocity of a single bubble simulated with an Eulerian two-fluid method is investigated. This study is part of the development of an elaborated Eulerian two-fluid framework, which is able to predict complex flow phenomena as arising in nuclear reactor safety research issues. Such flow phenomena cover a wide range of interfacial length scales. An important aspect of the simulation method is the distinction into small flow structures, which are modeled, and large structures, which are resolved. To investigate the requirements on the numerical grid for the simulation of such resolved structures the velocity of rising gas bubbles is a good example since theoretical values are available. It is well known that the rise velocity of resolved bubbles is clearly underestimated in a one-fluid approach if they span over only few numerical cells. In the present paper it is shown that in the case of the two-fluid model the bubble rise velocity depends only slightly on the grid size. This is explained with the use of models for the gas–liquid interfacial forces. Good approximations of the rise velocity and the bubble shape are obtained with only few grid points per bubble diameter. This result justifies the resolved treatment of flow structures, which cover only few grid cells. Thus, a limit for the distinction into resolved and modeled structures in the two-fluid context may be established. |
| Databáze: | OpenAIRE |
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