In the last decade, Fused Deposition Modeling (FDM) has gained popularity for allowing fabrication of pieces with complex shapes. The final quality is strongly linked to shape, size and surface finish strands deposited successively, which themselves depend on printing parameters extruded material properties. this work, we present an experimental characterization single strand Poly-Lactic Acid (PLA), by means high-speed visualization bead region between substrate nozzle, where molten polymer...

The aim of this work is to clarify some issues raised recently on the characterization water hammer, by presenting a numerical analysis multiphysics taking place. For purpose, commercial code CFD-ACE+ used with so-called full cavitation model, which takes into account effect absorption and desorption noncondensable gas. A comparison between two different compressibility models conducted, making use an inverse engineering technique, allows tracking medium speed sound. Finally, reproduction...

Cold-gas experiments are used to study the pressure oscillations occurring in solid rocket motors and performance of different ways passive control these oscillations. Previous studies stated that flow-acoustic coupling is mainly observed for nozzles including a cavity. The nozzle geometry has an effect on through between acoustic fluctuations induced by cavity volume vortices traveling front entrance. An important reduction (1 order magnitude) obtained, both axial radial flow injection...

Paints and coatings often feature interfacial defects due to disturbances during the deposition process, which, if they persist until solidification, worsens product quality. In this article, we investigate stability of a thin liquid film dragged by vertical substrate moving against gravity, fundamental flow configuration in various coating processes. The receptivity three-dimensional is analyzed with Direct Numerical Simulations (DNS) an in-house Integral Boundary Layer (IBL) model. latter...

The aim of this work is to study the fluid hammer and related multiphase phenomena taking place in a confined environment, where pressurized liquid faces vacuum conditions after opening an isolation valve. This paper describes experimental facility built for purpose, tests performed, shows comparison with numerical results obtained transient one-dimensional software based upon conservation equations. Because front moving along pipe are complex difficult interpret, graphical tool by means...

After studying the performance and characteristics of actual laminar flowmeters a new disposition for this type sensors is proposed in such way that measurement errors introduced by intrinsic nature device can be minimized. The preliminary study shows developing entry region introduces non-linearity effects all these devices. These bring about not only errors, but also change slope linear calibration respect Poiseuille relation. subsequent analysis on how reduced, introduced. This makes used...

In solid propellant rocket motors incorporating a submerged nozzle, the entrapment of liquid residues combustion in cavity formed surrounding nozzle integration part can lead to accumulation slag with considerable mass. The goal present study is characterize experimentally driving parameters stagnant area modelling cavity. Furthermore, experimental database used for validating numerical tool as well. article summary VKI (von Karman Institute) research carried out during last four years...

This paper aims at evaluating the sensitivity of numerical simulations patch and sheet/cloud cavitation to turbulence modeling in 2D.The periodic phenomena related cavity shedding cloud formation on a partially cavitating NACA0015 foil are studied within wide range conditions, relatively coarse meshes.The finite volume CFD package OpenFoam is used.A Homogeneous Equilibrium Approach employed, which achieved through transport equation for vapor fraction.The effect analyzed, comparing results...

Incorporating a submerged nozzle for solid propellant rocket motors, the resulting cavity formed in vicinity of integration part enhances entrapment liquid residues combustion and leads to accumulation slag with considerable mass. As first step assessment, an experimental numerical investigation single-phase internal flowfield is performed tool validated. The measurements are carried out cold-gas simplified model which flow injected from forward end (no wall injection). Simultaneously,...

In solid propellant rocket motors incorporating a submerged nozzle, the entrapment of liquid residues combustion in cavity formed surrounding nozzle integration part can lead to accumulation slag with considerable mass. The long-term goal present study is characterise experimentally driving parameters stagnant area modelling cavity. experimental database will be used for validation numerical tool. article measurements are shown two-phase flow condition using coldgas simplified model...

We investigate the dynamics of a gas jet impinging perpendicular to thin liquid film dragged by rising vertical substrate. This configuration is relevant jet-wiping process in hot-dip galvanization and it unstable. Previous studies analysed instability case liquids with low Kapitza numbers (highly viscous liquids), more amenable experimental numerical investigations. work extends previous investigations focusing on wiping at much higher numbers, which are galvanizing process. The simulations...

Cold gas experiments are used to study the pressure oscillations occurring in solid rocket motors (SRM) and performance of different ways passive control these oscillations. Previous studies stated that flow–acoustic coupling is mainly observed for nozzles including cavity. The nozzle geometry has an effect on through a between acoustic fluctuations induced by cavity volume vortices traveling front entrance. most important reduction obtained removing located around head. It been firstly...

When a pressurized liquid enters pipeline with closed end and under vacuum conditions, the resulting front suddenly is brought to rest at of pipe. This type flow configuration found in propulsion systems satellites during priming operation induces fluid hammer followed by column separation, generating multiphase gas/vapor bubble. paper aims explaining separation mechanism solving momentum equation for moving when occurs applying integral form conservation principles expansion compression...

The main objective of this work is the development a Computational Fluid Dynamics model coupled with structural code for simulation and optimization fishing gears. As nets are highly deformable structures under influence incident water, use merely empirical correlations hydrodynamic forces, such as those used in many codes, does not provide precise predictions their behaviour. coupling between problem effects makes it necessary to tackle through new "fluid–structure interaction" approach,...

In this work, we build a novel numerical approach to investigate the behaviour of coating flow in process hot-dip galvanization. The latter involves strong interaction between liquid film transported by moving strip and high speed gas jet. solver combines high-fidelity model for jet with simplified film. is that resolves OpenFOAM, an open- source CFD software built from C++ libraries. in-house finite volume implemented Python. communication both models handled plug-in coupling preCICE.