in this paper, direct numerical simulation of two-phase incompressible gas-liquid flow for simulation of bubble motion in a microtube is presented. microtube radius is 10 µm. the interface is tracked using volume of fluid (vof) method with continuous surface force (csf) model. the flow is solved using a finite volume scheme, based on piso algorithm. numerical simulation is performed on a axisym...

This work is a continuation of experimental and computational studies of the internal flow field of a large-scale Danfoss atomizer presented at an earlier ILASS conference [1,2]. Fluent 6.1 is used to simulate the flow through the large-scale atomizer. The two-phase flow is modeled using three approaches: 1) a volume of fluid (VOF) method using a laminar flow assumption, 2) a VOF method using l...

The continuum surface force (CSF) method has been extensively employed in the volume-of-fluid (VOF), level set (LS) and front tracking methods to model the surface tension force. It is a robust method requiring relatively easy implementation. However, it is known to generate spurious currents near the interface, which may lead to disastrous interface instabilities and failures of grid convergen...

In this paper a novel numerical approach is presented for solving the transient incompressible fluid flow problems with free surfaces in generalized two-dimensional curvilinear coordinate systems. Solution algorithm is a combination of implicit real-time steps and explicit pseudo-time steps. Governing fluid flow equations are discretized using a collocated finite-volume mesh. Convective terms a...

Forced convective condensation in vertical channel is investigated numerically. The condensation boundary layers that occur due to temperature difference between the walls and saturation temperature of steam is simulated by the volume of fluid (VOF) method. The effect of variations in the hydraulic diameter, steam velocity, Re number and temperature difference between the wall and saturation te...

We presented a new approach to calculating normal vectors to fluid interfaces in [JCP, 226:774–797, 2007 ], by advecting unit normals along with an interface. In this paper, we introduce an implementation of the method in an interfacial flow solver. The advected normals are used to compute the interface curvature for calculating the surface tension force, and for reconstructing the interface in...

A mathematical model to describe the globular transfer in gas metal arc welding is developed. This work is both theoretical and experimental. Using the volume-of-fluid (VOF) method, the fluid-flow and heat-transfer phenomena during the impingement of a droplet on a solid substrate, arc striking, the impingement of multiple droplets on the molten pool and finally the solidification after the arc...

We study microreactors with internal fields of posts as typical examples of structured microreactors to elucidate flow fields and their implications for mass transfer. Laser-induced fluorescence (LIF) visualization combined with image analysis is used to systematically quantify key features such as interfacial area, phase holdup and the characteristics of the post-wetting layer. The subsequent ...

Two-fluid dynamics is a challenging subject, rich both in physics and in practical applications, which range from manufacturing to lubricated transport. Mechanisms unique to a flow can be exploited to enhance functionality in applications. For example, density-matching can be used to depress the effect of gravity, or of centripetal acceleration in rotating systems, making it possible to manipul...