Amirsaman Farrokhpanah

Apple Inc.

A three-dimensional model is developed for predicting impact and solidification behaviour of droplets generated by Suspension Plasma Spraying (SPS). The model utilizes Smoothed Particle Hydrodynamics (SPH) discretization of enthalpy equation to capture the phase change process. Surface tension is modelled as an internal force between all particles...

A numerical study of suspension plasma spraying (SPS) is presented in the current work. The liquid suspension jet is replaced with a train of droplets containing the suspension particles injected into the plasma flow. Atomization, evaporation, and melting of different components are considered for particles as they travel towards the substrate. Eff...

When modelling phase change, the latent heat released (absorbed) during solidification (melting) must be included in the heat transfer equation. In this paper, different SPH methods for the implementation of latent heat, in the context of transient heat conduction, are derived and tested. First, SPH discretizations of two finite element methods are...

Equilibrium contact angle of liquid drops over horizontal surfaces has been modeled using smoothed particle hydrodynamics (SPH). The model is capable of accurate implementation of contact angles to stationary and moving contact lines. In this scheme, the desired value for stationary or dynamic contact angle is used to correct the profile near the t...

A three-dimensional model is presented for the prediction of solidification behavior using a nonlinear transformation of the enthalpy equation in a Smoothed Particle Hydrodynamics (SPH) discretization. The effect of phase change in the form of release and absorption of latent heat is implemented implicitly as variable source terms in the enthalpy c...

The ECAP experiment (Evaporative Coatings at Atmosphere Pressure) was developed at CPMI (Center for Plasma Materials Interaction at UIUC) as a device and a method for multicomponent metal coatings deposition at atmosphere pressure utilizing a 2.45 GHz microwave plasma torch. The device is capable of coating deposition from a solid metal state and f...

A study of flight, impact, and solidification of molten ceramic droplets generated by suspension plasma spraying (SPS) is conducted. A three-dimensional model is developed for predicting behavior of droplets generated by SPS impacting a solid substrate. The model combines Smoothed Particle Hydrodynamics (SPH) integral interpolations with enthalpy f...

Wire arc is an effective and affordable type of coating process. Detailed understanding of it helps improving design and optimization of currently available guns. In wire arc process, an arc forming between two charged wires generates enough heat to melt the metallic wires. Blow of air at high velocity over this bath of molten metal leads to atomiz...

A 3D Smoothed Particle Hydrodynamics (SPH) model is developed for prediction of solidification and impact of droplets generated in Suspension Plasma Spraying (SPS): 1) Solidification added by non-linear transformation of enthalpy equation in SPH discretization 2)New model validated against various experimental, analytical, and numerical results 3)...

Yttria stabilized zirconia coatings were deposited through suspension plasma spray (SPS) using a commercial F4-VB torch and a novel torch designed in Centre for Advanced Coating Technologies. The effects of suspension solvent, plasma gas compositions, arc voltage fluctuations and standoff distances on coatings microstructures were investigated. The...

In this work, a numerical model is developed and used to investigate changes that occur to ceramic suspensions in a plasma jet. The model accounts for atomization processes, evaporation of the fluid phase, and melting of the solid phase. Attention is also given to changes in the physical properties of the suspension mixture as the liquid phase evap...

Comprehensive study of the wire arc thermal spray technology will allow for better design and optimization of guns. In wire arc spray, a feed of two electrically-charged wires are melted using an arc. This bath of molten metal goes through an atomization process with a high pressure air being blown upon it. Flow of air will then carry the generated...

Multiphase Smoothed Particle Hydrodynamics (SPH) method has been used to study the jet breakup phenomena. It has been shown that this method is well capable of capturing different jet breakup characteristics. The value obtained for critical Weber number here in transition from dripping to jetting is a very good match to available values in literatu...

Investigation and benchmarking a numerical method is one of the main parts of its development. Any numerical technique needs precise evaluation of its accuracy and efficiency before it can be fully trusted. In the present work, fluid flow in two dimensional flow fields over columns of cylinders in a periodic domain is studied using single relaxatio...

A parallel GPU compatible Lagrangian mesh free particle solver for multiphase fluid flow based on SPH scheme is developed and used to capture the interface evolution during droplet impact. Surface tension is modeled employing the multiphase scheme of Hu et al. (2006). In order to precisely simulate the wetting phenomena, a method based on the work...

A parallel GPU compatible Lagrangian mesh free particle solver for multiphase fluid flow based on Smoothed Particle Hydrodynamics (SPH) scheme is developed and used to capture the interface evolution during droplet impact. To solve Navier-Stokes equations, the computational domain is discretized using fluid particles. Surface tension is modeled emp...