Simulation of a Gas Tungsten Arc Welding Process in COMSOL

The purpose of this project is to model the transport phenomena (heat transfer, fluid flow, and current flow) in a gas tungsten arc welding (GTAW) process using COMSOL Multiphysics. The model development will start with developing two separate models - an arc model and a weld pool model and end with an integrated arc - weld pool model to simulate the interaction between the arc and the weld pool. The integrated arc-weld pool model will be used to study the effects of some welding process parameters, such as the anode materials, the arc length, and the shielding gas, on the final weld quality

Numerical Study on the Thermal Performance of Embedded Heat Pipes for CPU Cooling

Thermal management of central processing units (CPU) becomes more challenging in the development and production of high performance computers with faster and smaller size CPUs. Heat pipes are two-phase cooling devices with an effective thermal conductivity over 200 times higher than that of a copper heat sink. In addition, heap pipes have light weight, low cost and the flexibility of many different sizes and shape options which can be embedded into the metallic heat sink to provide more efficient thermal management. In this project, CFD was used to study a heap pipe embedded CPU cooler. The simulated results is validated with the experimental data for the same CPU cooler. Golf ball fans were also introduced to replace the stock fans in the CPU cooler to enhance the heat transfer and lower the operating temperature. The detailed distributions of temperature, velocity, and pressure were used to analyze the performance of the CPU cooler in both cases and found the golf ball fans are more effective than the stock fans

Evaluating Laguerre-Gaussian beams with an invariant parameter

We define a new parameter about Laguerre-Gaussian (LG) beams, named $Q^{l}_{p}$, which is only related to mode indices $p$ and $l$. This parameter is able to both evaluate and distinguish LG beams. The $Q^{l}_{p}$ values are first calculated theoretically and then measured experimentally for several different LG beams. Another mode quality parameter, $M^{2}$ value, is also measured. The comparison between $Q^{l}_{p}$ and $M^{2}$ shows same trend for the quality of LG mode, while the measurement of $Q^{l}_{p}$ is much easier than $M^{2}$.Comment: 3.1 pages, 4 figures, 1 tabl

Droplet Acceleration in the Arc

This paper simulates the acceleration of the droplet in the arc during gas metal arc welding process. After a droplet is detached from the electrode, it is accelerated in the high temperature and high velocity arc to the workpiece. The droplet is subjected to several forces, such as the arc plasma shear stress, arc pressure force, surface tension force, gravity force, and electromagnetic force. A comprehensive model is used to simulate the changes of droplet shape, temperature, and velocity during the acceleration in the arc. The transient interaction of droplet and arc plasma is through coupled boundary conditions, thus, no assumptions are needed to simulate the droplet acceleration. The simulated results were compared with the published experimental data and an agreement was found