ISSN:0098-6445    

DOI:10.1080/00986449608936407

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A Lagrangian slug tracking model for dynamic gas-liquid slug flow in pipelines of varying inclinations has been formulated and implemented in C + + using an object-oriented approach. Slugs and bubbles are discrete computational objects which are coupled by exchange of mass and momentum, and organized in linked lists

ISSN:0098-6445    

DOI:10.1080/00986449608936408

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A study of the linear stability of a laminar flow of an oil-water system in an inclined channel is presented. A novel shear-mode of instability, which is necessarily decaying in plane Poiseuille flow, is found to be the primary instability in certain situations. When the channel is sufficiently inclined, the long-wave mode can become unstable, regardless of the total volumetric flow rate of the fluids The consequences to oil transport are discussed.

ISSN:0098-6445    

DOI:10.1080/00986449608936409

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper in memory of Pr Dukler summarizes a set of experiments on bubbly shear flows carried out by two groups, in Toulouse and in Lyon. Homogeneous shear flows, plane mixing layer, boundary layer on a flat plate and sudden area expansion have been investigated, for low and moderate void fraction. Measurements of mean liquid velocity show that the main features of the corresponding single phase flow are conserved, in particular self-similarity of the mean velocity profiles. However, the turbulent field is strongly modified. The transverse interfacial momentum transfer has been evaluated, and proves to be dominated by instantaneous local forces, which are not usually taken into account in eulerian models.

ISSN:0098-6445    

DOI:10.1080/00986449608936410

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A novel approach to modelling transient slug flow is presented. Aspects of current physical descriptions of slug flow, required as closure laws for the models are briefly reviewed. It is demonstrated how the dynamics of large scale changes in slug flow may be simulated, by incorporating a unit cell type of slug flow model into numerical transient two-fluid models.

ISSN:0098-6445    

DOI:10.1080/00986449608936411

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Many attempts made in modelling stratified two-phase flow for predicting the operational flow characteristics (pressure drop, holdup, etc.) assume mostly plane interface between the phases. Obviously, the interaction between the stratified layers and the resulting flow characteristics may be significantly affected by the configuration of the interface. Moreover, complete analytical solutions for stratified flows in circular conduits a re not yet available even for laminar flows with plane interface and most of previous studies resort to average two-fluid modelling.

ISSN:0098-6445    

DOI:10.1080/00986449608936412

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0098-6445    

DOI:10.1080/00986449608936413

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Based on the experiments carried out over the past decade at microgravity conditions, an overview of our current knowledge of bubbly and slug flows is presented. The transition from bubble to slug flow, the void fraction and the pressure drop are discussed from the data collected in the literature. The transition from bubble to slug flow may be predicted by introducing a critical void fraction that depends on the fluid properties and the pipe diameter: however, the role of coalescence which controls this transition is not clearly understood. The void fraction may be accurately calculated using a drift-flux model: it is shown from local measurements that the drift of the gas with respect to the mixture is due to the non uniform radial distribution of void fraction. The pressuredrop happens to be controlled by the liquid flow for bubbly flow whereas for slug flow the experimental results show that pressure drops is larger than expected. From this study, the guidelines for future research in microgravity are given.

ISSN:0098-6445    

DOI:10.1080/00986449608936414

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new model to calculate the two-phase flow pressure change across a sudden expansion in a duct area was developed and checked against data measured with mixtures of air and water, aqueous glycerol, watery calcium nitrate and with refrigerant R 12. In the model all relevant physical parameters are included and, in contrast to equations in the literature, the entrainment of liquid in the gas stream is considered. The predictions are validated for a wide range of conditions, pipe diameters and physical properties typically encountered in industrial pipe line systems: Calculations based on the new approach are sufficiently accurate for engineering purposes.

ISSN:0098-6445    

DOI:10.1080/00986449608936415

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Due to the increasing consumption of energy and the green house effect caused by C02nudear power stations have been playing more important role than ever in the electric power generation. And both the economy and the safety of the nuclear power station are strongly demanded. One of the restriction in the thermal design of the safe and economic nuclear reactor, especially in BWR is pointed out to be the heat removal from the fuel rods near the rods supporting spacer.

ISSN:0098-6445    

DOI:10.1080/00986449608936416

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor