A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used t...

This paper presents a novel approach for simulating incompressible two-phase flows by combining a conservative level set technique and the ghost-fluid method. Following the ideas of Olsson and Kreiss (2005), the liquid-gas interface is localized using a hyperbolic tangent level set that is transported and reinitialized using fully conservative numerical schemes. Mass conservation issues are gre...

A reliable description of dense gas–solid two-phase flows of Geldart A particles in gasfluidized beds at life-size scale is of great practical importance in process industries. The classical two-fluid model, based on the kinetic theory of granular flows (KTGF), provides a very promising theoretical framework for predicting large-scale gas–solid twophase flows. However, thus far the two fluid mo...

We propose a two-phase model having a Newtonian rheology for the fluid phase and friction for the particle phase to describe bed-load transport in laminar pipe flows. This model is able to provide a description of the flow of the mobile granular layer. When the flow is not significantly perturbed, simple analytical results of the particle flux varying cubically with the Shields number can be ob...

A conservative level-set model for direct simulation of two-phase flows with thermocapillary effects at dynamically deformable interface is presented. The Navier-Stokes equations coupled with the energy conservation equation are solved by means of a finitevolume/level-set method. Some numerical examples including thermocapillary motion of single and multiple fluid particles are computed by mean...

This experimental study deals with two-phase air-water flow generated in a vertical pipe measuring 35 mm in diameter. The complex nature of two-phase flow itself creates obstacles in detecting, monitoring and description of flow patterns, which are directly related to spatial and temporal distributions of concentration in the mixture. In addition to that, the difficulties in comparing results a...

In free-surface flows, some flow instabilities may be observed, for example in pooled stepped spillways and hydraulic jumps. These instabilities may include some pulsations and oscillations. Most traditional two-phase flow analyses would yield some air-water turbulent flow results combining the contributions of the slow fluctuations and of the turbulent motion. Herein a new turbulence decomposi...

Asymptotic methods for singularly perturbed delay differential equations are in many ways more challenging to implement than for ordinary differential equations. In this paper, four examples of delayed systems which occur in practical models are considered: the delayed recruitment equation, relaxation oscillations in stem cell control, the delayed logistic equation, and density wave oscillation...