7,211 research outputs found
Interfacial shear in adiabatic downward gas/liquid co-current annular flow in pipes
Interfacial friction is one of the key variables for predicting annular two-phase flow behaviours in vertical pipes. In order to develop an improved correlation for interfacial friction factor in downward co-current annular flow, the pressure gradient, film thickness and film velocity data were generated from experiments carried out on Cranfield University’s Serpent Rig, an air/water two-phase vertical flow loop of 101.6 mm internal diameter. The air and water superficial velocity ranges used are 1.42–28.87 and 0.1–1.0 m/s respectively. These correspond to Reynolds number values of 8400–187,000 and 11,000–113,000 respectively. The correlation takes into account the effect of pipe diameter by using the interfacial shear data together with dimensionless liquid film thicknesses related to different pipe sizes ranging from 10 to 101.6 mm, including those from published sources by numerous investigators. It is shown that the predictions of this new correlation outperform those from previously reported studies
Towards an Updatable Strategy Logic
This article is about temporal multi-agent logics. Several of these
formalisms have been already presented (ATL-ATL*, ATLsc, SL). They enable to
express the capacities of agents in a system to ensure the satisfaction of
temporal properties. Particularly, SL and ATLsc enable several agents to
interact in a context mixing the different strategies they play in a semantical
game. We generalize this possibility by proposing a new formalism, Updating
Strategy Logic (USL). In USL, an agent can also refine its own strategy. The
gain in expressive power rises the notion of "sustainable capacities" for
agents.
USL is built from SL. It mainly brings to SL the two following modifications:
semantically, the successor of a given state is not uniquely determined by the
data of one choice from each agent. Syntactically, we introduce in the language
an operator, called an "unbinder", which explicitely deletes the binding of a
strategy to an agent. We show that USL is strictly more expressive than SL.Comment: In Proceedings SR 2013, arXiv:1303.007
Numerical simulation of bubble generation in a T-junction
We present a numerical study of the formation of mini-bubbles in a 2D T-junction by means of the fluid dynamics numerical code JADIM. Numerical simulations were carried out for different flow conditions, giving rise to results on the behavior of bubble velocity, void fraction, bubble generation frequency and length. Numerical results are compared with existing experimental data thanks to non-dimensional analysis
Influence of contact angle boundary condition on CFD simulation of T-Junction
“This is a post-peer-review, pre-copyedit version of an article published in Microgravity Science and Technology. The final authenticated version is available online at: https://doi.org/10.1007/s12217-018-9605-x ”.In this work, we study the influence of the contact angle boundary condition on 3D CFD simulations of the bubble generation process occurring in a capillary T-junction. Numerical simulations have been performed with the commercial Computational Fluid Dynamics solver ANSYS Fluent v15.0.7. Experimental results serve as a reference to validate numerical results for four independent parameters: the bubble generation frequency, volume, velocity and length. CFD simulations accurately reproduce experimental results both from qualitative and quantitative points of view. Numerical results are very sensitive to the gas-liquid-wall contact angle boundary conditions, confirming that this is a fundamental parameter to obtain accurate CFD results for simulations of this kind of problems.Peer ReviewedPostprint (published version
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