Simulations of Electron Heating in a Capacitively Coupled Radio Frequency Micro-Thruster using Computational Fluid Dynamics

Beyond classic risk parameters non physiologic or oscillating wall shear stress (WSS) has been proven to act as a local factor for initiation and progression of atherosclerosis as well as for plaque rupture. Direct measurement of WSS in-vivo is difficult and restricted to animal models. Computational fluid dynamics (CFD) is a validated tool to compute flow parameters and WSS. For this purpose an exact model of the underlying patient specific geometry of the coronary tree is a prerequisite. Using 3D-IVUS or modern multislice computed tomographic coronary angiography (CTA) with submilimeter resolution these data can be provided. The aim of this study was to 1.) demonstrate feasibility of in-vivo CFD calculation of human coronaries based on CTA and 2.) to correlate the findings with radio frequency tissue information derived by intravascular ultrasound. We prospectively included 10 patients with suspected coronary artery disease who received CTA (Dual source 64 slice CT) and invasive conventional coronary angiography. Intravascular ultrasound and ECG-triggered radio frequency analysis (VH) was attempted in all three epicardial vessels. In the CTA-dataset the coronaries were segmented and a mesh model for CFD was generated. CFD calculations were performed using a commercial available software package with laminar flow and blood as a Newtonian fluid as boundary conditions. Coronary models were stationary with rigid vessel walls, while the pulsatile inflow characteristics was derived from invasive Doppler velocity measurement. Flow pattern calculations, vessel wall shear stress and IVUS analysis were successfully performed in 24/30 and 17/30 coronary arteries. The presence of high shear stress and non turbulent flow was inversely correlated with the presence of plaque as determined by intravascular ultrasound. No correlation of any CFD parameter with the radio frequency tissue information could yet be observed. The findings of the present study demonstrate the feasibility of assessing fluid tissue interactions in human coronary arteries using CTA and its correlation to invasive findings. The possible impact of CFD parameters on risk- and treatment stratification has to be determined in a large scale prospective trial.

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Simulation of main plasma parameters of a cylindrical asymmetric capacitively coupled plasma micro-thruster using computational fluid dynamics

Frontiers in Physics ◽

10.3389/fphy.2014.00080 ◽

2015 ◽

Vol 2 ◽

Cited By ~ 14

Author(s):

Amelia Greig ◽

Christine Charles ◽

Roderick W. Boswell

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Plasma Parameters ◽

Capacitively Coupled ◽

Capacitively Coupled Plasma

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Electron Heating Dynamics in Capacitively Coupled Plasmas Radio-Frequency Discharges at Low Pressures

2020 IEEE International Conference on Advances in Electrical Engineering and Computer Applications( AEECA) ◽

10.1109/aeeca49918.2020.9213688 ◽

2020 ◽

Author(s):

Lulu Zhao ◽

Tagra Samir ◽

Huizhen Yan

Keyword(s):

Radio Frequency ◽

Electron Heating ◽

Capacitively Coupled ◽

Radio Frequency Discharges ◽

Coupled Plasmas ◽

Low Pressures

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Computational Fluid Dynamics Analysis of Particle Deposition Induced by a Showerhead Electrode in a Capacitively Coupled Plasma Reactor

Coatings ◽

10.3390/coatings11081004 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1004

Author(s):

Ho Jun Kim ◽

Jung Hwan Yoon

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Particle Deposition ◽

Complex Geometry ◽

Plasma Reactor ◽

Electrode Spacing ◽

Plasma Discharges ◽

Capacitively Coupled ◽

Computational Fluid Dynamics Analysis ◽

Capacitively Coupled Plasma

Defect formation in the deposition of thin films for semiconductors is not yet sufficiently understood. In a showerhead-type capacitively coupled plasma (CCP) deposition reactor, the showerhead acts as both the gas distributor and the electrode. We used computational fluid dynamics to investigate ways to enhance cleanliness by analyzing the particle deposition induced by the showerhead electrode in a CCP reactor. We analyzed particle transport phenomena using a three-dimensional complex geometry, whereas SiH4/He discharges were simulated in a two-dimensional simplified geometry. The process volume was located between the RF-powered showerhead and the grounded heater. We demonstrated that the efficient transportation of particles with a radius exceeding 1 μm onto the heater is facilitated by acceleration inside the showerhead holes. Because the available space in which to flow inside the showerhead is constricted, high gas velocities within the showerhead holes can accelerate particles and lead to inertia-enhanced particle deposition. The effect of the electrode spacing on the deposition of particles generated in plasma discharges was also investigated. Smaller electrode spacing promoted the deposition of particles fed from the showerhead on the heater, whereas larger electrode spacing facilitated the deposition of particles generated in plasma discharges on the heater.

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