R. Coker, J. Knox, K. Kittredge
NASA - Marshall Space Flight Center, Huntsville, AL, USA
All spacecraft systems must be minimized with respect to mass, power, and volume. Here, we focus on current efforts to improve system efficiency and reliability for water separation systems to be used on crewed vehicles. These development efforts combine sub-scale systems testing and multi-physics simulations to evaluate candidate approaches. The best performing options will then be ...
S. Qidwai, N. Kota, V. DeGiorgi
Naval Research Laboratory, Washington, DC, USA
Science Applications International Corporation, Washington, DC, USA
Pitting corrosion is a complex phenomenon where rates of: i) chemical reactions, ii) diffusion of various species involve in those reactions, and iii) species dissolution at the metal-electrolyte interface are fully dependent on each other, except under special conditions or assumptions. One set of such conditions is that: a) there are no species concentration gradients due to the rapid mixing ...
Optimization of Artificial Diffusion Stabilization Techniques and Corresponding Mesh Density Distribution in Drift Dominated Transport of Diluted Species
J. Jadidian, M. Zahn, N. Lavesson, O. Widlund, K. Borg
Massachusetts Institute of Technology, Cambridge, MA, USA
ABB Corporate Research, Västerås, Sweden
This paper presents an optimized combination of artificial diffusion techniques to stabilize a drift dominated streamer discharge model which includes COMSOL Multiphysics’ Transport of Diluted Species modules for positive ion, negative ion, and electron charge densities, coupled through the Electrostatic module. A Thermal Conduction and Convection module is responsible for the heat transfer in ...
Simulation of Acoustic Energy Harvesting Using Piezoelectric Plates in a Quarter-Wavelength Straight-Tube Resonator
B. Li, J.H. You
Southern Methodist University, Dallas, TX, USA
An acoustic energy harvesting mechanism at low frequency (~200 Hz) using lead zirconate titanate (PZT) piezoelectric cantilever plates placed inside a quarter-wavelength straight-tube resonator has been studied using COMSOL Multiphysics 4.3 and compared with experimental data. When the tube resonator is excited by an incident wave at its acoustic eigenfrequency, an amplified acoustic resonant ...
A. Marchidan, T. Sullivan, J. Palladino
Trinity College, Hartford, CT, USA
COMSOL Multiphysics was used to design a binocular load cell. A three-dimensional linear solid model of the load cell spring element was studied to quantify the high-strain regions under loading conditions. The load cell was fabricated from 6061 aluminum, and general purpose Constantin alloy strain gages were installed at the four high-strain regions of the spring element. The four gages were ...
Pulsed Eddy Current Probe Development to Detect Inner Layer Cracks Near Ferrous Fasteners Using COMSOL Modeling Software
V. Babbar, P. Whalen, T. Krause
Department of Physics, Royal Military College of Canada, Kingston, ON, Canada
Surface breaking cracks in conductive structures can be detected by conventional eddy current techniques. However, it is very difficult to detect inner layer defects in multilayered conductive structures either by conventional eddy current or ultrasonic methods. The transient/pulsed eddy current (PEC) technology can potentially overcome these limitations and is being developed for detection of ...
Analysis of Superheater Tubes with Mutual Irradiation as Applied to a Solar Receiver Steam Generator
N. Lemcoff, S. Wyatt
Rensselaer Polytechnic Institute, Hartford, CT, USA
Alstom Power, Windsor, CT, USA
The objective of this paper is to analyze the temperature variations within a superheater tube of a solar receiver steam generator. The tube is heated by concentrated, collimated solar irradiation with major cooling by an internal steam flow. The influence of heat loss by radiation, internal convection, and conduction are considered. Analytical models are obtained for an isolated tube, and the ...
S. Arslan, J. Brown
Lawrence Technological University, Southfield, MI, USA
The rapid increase in power densities of integrated circuits has induced a significant interest in new reliable and high heat flux cooling technologies. The implication of such growth is the increased need for more efficient and more compact cooling mechanisms. Promising research has been conducted in the area of MEMS cooling devices, taking advantage of the increased heat transfer ...
J.E. Rayas-Sánchez, J. Aguilar-Torrentera, Z. Brito-Brito, J.C. Cervantes-González, C.A. López
Universidad Jesuita de Guadalajara, Tlaquepaque, Jalisco, Mexico
Intel Guadalajara Design Center, Tlaquepaque, Jalisco, Mexico
We perform EM simulations of a low-pass microstrip filter consisting of a cross-junction open stub and two unit sections implemented as defected ground structures (DGS). The defect introduced by unit sections corresponds to an etched lattice on the copper backside ground plane. The filter presents wide and deep attenuation characteristics in the stopband. Different model implementations were ...
Modeling and Analysis of a Direct Expansion Geothermal Heat Pump (DX): Part I-Modeling of Ground Heat Exchanger
C. Rousseau, J. Fannou, L. Lamarche, M. Ouzzane
École de Technologie Supérieure, Montréal, Québec, Canada
CanmetENERGY, Varennes, Québec, Canada
Geothermal heat pump technology is actually one of the most interesting processes to provide heat and cold to a building. In this study, a model of the ground exchanger of a direct expansion geothermal heat pump (DX) is going to be presented in 1 dimension. The model represents the phase change of the refrigerant, here Chlorodifluoromethane R22, with governing continuity, momentum and energy ...