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1
IKEDA, Kei. "4034 Plasma Equipment Modeling using CFD-ACE+." Proceedings of The Computational Mechanics Conference 2005.18 (2005): 461–62. http://dx.doi.org/10.1299/jsmecmd.2005.18.461.
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GE, JIE, XUAN LIU, YI YANG, YIXU SONG, and TIANLING REN. "REACTION SIMULATION AND EXPERIMENT OF A Cl2/Ar INDUCTIVELY COUPLED PLASMA FOR ETCHING OF SILICON." Surface Review and Letters 21, no. 03 (June 2014): 1450038. http://dx.doi.org/10.1142/s0218625x14500383.
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As the key feature size keeps shrinking down, inductively coupled plasma (ICP) has been widely used for etching. In this study, a commercial ICP etcher filled with Cl 2/ Ar mixture was simulated. The simulation was based on a commercial software CFD-ACE+, which is a multi-module solver. For the simulation part, CFD-ACE module was used for reactor scale and CFD-TOPO module was used for feature scale simulation. We have reached a reasonable agreement between the simulative and experimental results. Specifically, the different causes of sidewall bowing and microtrenching were discussed. We also analyzed the causes of special profile as trench width scaling down. Moreover, the agreement validates correctness of the chemistry mechanism, so it can be used as guidance for the process designing and manufacturing equipment improvement.
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Lin, Jing Chuen, An Shik Yang, and Li Yu Tseng. "Use of Micro Synthetic Jet Actuators for Boundary Layer Flow Control." Advanced Materials Research 74 (June 2009): 157–60. http://dx.doi.org/10.4028/www.scientific.net/amr.74.157.
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The main purpose of active flow control research is to develop a cost-effective technology that has the potential for inventive advances in aerodynamic performance and maneuvering compared to conventional approaches. It can be essential to thoroughly understand the flow characteristics of the formation and interaction of a synthetic jet with external crossflow before formulating a practicable active flow control strategy. In this study, the theoretical model used the transient three-dimensional conservation equations of mass and momentum for compressible, isothermal, turbulent flows. The motion of a movable membrane plate was also treated as the moving boundary by prescribing the displacement on the plate surface. The predictions by the computational fluid dynamics (CFD) code ACE+® were compared with measured transient phase-averaged velocities of Rumsey et al. for software validation. The CFD software ACE+® was utilized for numerical calculations to probe the time evolution of the development process of the synthetic jet and its interaction within a turbulent boundary layer flow for a complete actuation cycle.
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Xu, Qing, Yu-Xing Li, Xiao-Ning Li, Jia-Bin Wang, Fan Yang, Yi Yang, and Tian-Ling Ren. "Simulation of SiO2 etching in an inductively coupled CF4 plasma." Modern Physics Letters B 31, no. 06 (February 28, 2017): 1750042. http://dx.doi.org/10.1142/s0217984917500427.
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Plasma etching technology is an indispensable processing method in the manufacturing process of semiconductor devices. Because of the high fluorine/carbon ratio of CF4, the CF4 gas is often used for etching SiO2. A commercial software ESI-CFD is used to simulate the process of plasma etching with an inductively coupled plasma model. For the simulation part, CFD-ACE is used to simulate the chamber, and CFD-TOPO is used to simulate the surface of the sample. The effects of chamber pressure, bias voltage and ICP power on the reactant particles were investigated, and the etching profiles of SiO2 were obtained. Simulation can be used to predict the effects of reaction conditions on the density, energy and angular distributions of reactant particles, which can play a good role in guiding the etching process.
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Crocker, D. S., E. J. Fuller, and C. E. Smith. "Fuel Nozzle Aerodynamic Design Using CFD Analysis." Journal of Engineering for Gas Turbines and Power 119, no. 3 (July 1, 1997): 527–34. http://dx.doi.org/10.1115/1.2817017.
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The aerodynamic design of airflow passages in fuel injection systems can be significantly enhanced by the use of CFD analysis. Attempts to improve the efficiency of the fuel nozzle design process by using CFD analyses have generally been unsuccessful in the past due to the difficulties of modeling swirling flow in complex geometries. Some of the issues that have been obstacles to successful and timely analysis of fuel nozzle aerodynamics include grid generation, turbulence models, and definition of boundary conditions. This study attempts to address these obstacles and demonstrate a CFD methodology capable of modeling swirling flow within the internal air passages of fuel nozzles. The CFD code CFD-ACE was used for the analyses. Results of nonreacting analyses and comparison with experimental data are presented for three different fuel nozzles. The three nozzles have distinctly different designs (including axial and radial inflow swirlers) and thus demonstrate the flexibility of the design methodology. Particular emphasis is given to techniques involved in predicting the effective flow area (ACd) of the nozzles. Good agreement between CFD predictions of the ACd (made prior to experiments) and the measured ACd was obtained. Comparisons between predicted and measured velocity profiles also showed good agreement.
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Vedantam, S., K. E. Wardle, T. V. Tamhane, V. V. Ranade, and J. B. Joshi. "CFD Simulation of Annular Centrifugal Extractors." International Journal of Chemical Engineering 2012 (2012): 1–31. http://dx.doi.org/10.1155/2012/759397.
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Annular centrifugal extractors (ACE), also called annular centrifugal contactors offer several advantages over the other conventional process equipment such as low hold-up, high process throughput, low residence time, low solvent inventory and high turn down ratio. The equipment provides a very high value of mass transfer coefficient and interfacial area in the annular zone because of the high level of power consumption per unit volume and separation inside the rotor due to the high g of centrifugal field. For the development of rational and reliable design procedures, it is important to understand the flow patterns in the mixer and settler zones. Computational Fluid Dynamics (CFD) has played a major role in the constant evolution and improvements of this device. During the past thirty years, a large number of investigators have undertaken CFD simulations. All these publications have been carefully and critically analyzed and a coherent picture of the present status has been presented in this review paper. Initially, review of the single phase studies in the annular region has been presented, followed by the separator region. In continuation, the two-phase CFD simulations involving liquid-liquid and gas-liquid flow in the annular as well as separator regions have been reviewed. Suggestions have been made for the future work for bridging the existing knowledge gaps. In particular, emphasis has been given to the application of CFD simulations for the design of this equipment.
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WU, YEONG-JEN, and WEI-HSIANG LAI. "SIMULATION OF PIEZOELECTRIC JELLYFISH POWER GENERATOR." Modern Physics Letters B 24, no. 13 (May 30, 2010): 1325–28. http://dx.doi.org/10.1142/s0217984910023530.
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The energy problem is getting increasingly serious. As such, unused energy recovery technology is crucial for environmental protection, which has been investigated extensively. Several methods have been developed to utilize scavenged energy from the environment, such as waste heat, solar energy, wind energy, and tides energy to convert into useful power. There is a new idea of piezoelectric jellyfish generator which combines the utilization of sea wave and vibration energy. When sea wave passes through the jellyfish, the wave causes the tentacles to vibrate. The tentacles is made of piezoelectric polymer which can convert the strain energy into electrical energy. This paper discusses about the piezoelectric jellyfish's tentacles being disturbed by wave in the sea. We employed the commercial CFD software CFD-ACE+ 2006 to simulate this phenomenon. The parameters including its tentacle length (L) and wave propagating function (Y) are studied which affect the piezoelectric jellyfish capacity to generate power.
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Sarpkaya, T., M. de Angelis, and C. Hanson. "Oscillating Turbulent Flow With or Without a Current About a Circular Cylinder." Journal of Offshore Mechanics and Arctic Engineering 119, no. 2 (May 1, 1997): 73–78. http://dx.doi.org/10.1115/1.2829056.
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CFD analyses of two benchmark, two-dimensional, sinusoidally oscillating, turbulent flows (one with zero mean and one with nonzero mean) at relatively large Reynolds and Keulegan-Carpenter numbers and relative current velocities, have been performed with CFD-ACE, a Favre-averaged Navier-Stokes (FANS) code. The primary purpose of the investigation was a critical assessment of the computational accuracy of time-dependent turbulent flows with large-scale unsteadiness. A number of turbulence models, including the standard k-ε, re-normalization group (RNG) based k-ε, and low-Reynolds number model have been employed. Among others, a second order in time, second order in space, second-level predictor-corrector finite-difference scheme has been used. The analysis produced the time-dependent in-line and transverse forces, the force coefficients, instantaneous velocity, vorticity, and pressure distributions, and streamlines. Representative results are compared with each other and with those obtained experimentally.
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Xu, Xia, Juan Feng, and Ling Tian. "Modeling and Optimization of Process Parameters of a DF-CCP Etcher Chamber." Key Engineering Materials 572 (September 2013): 213–16. http://dx.doi.org/10.4028/www.scientific.net/kem.572.213.
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Dual-frequency capacitively coupled plasma (DF-CCP) etcher has become the mainstream in dielectric etcher. By building a 2D axisymmetric model of 300mm DF-CCP etcher in CFD-ACE+ software, plasma simulation experiments are carried out by orthogonal design. Then a process model based on simulation results is proposed to analysis influence of key process parameters including high frequency voltage, low frequency voltage, and chamber pressure and center/edge flow ratio on chamber plasma characteristics. Finally, to get high plasma uniformity and plasma density, process optimizations are carried out.
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Zhao, Qiao Le, Yu Cheng Lin, and Qin Gan Huang. "A DC Voltage Driven Flow-Through Electroporation Microchip." Advanced Materials Research 60-61 (January 2009): 44–48. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.44.
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Differing with the traditional way to perform electroporation (EP) by using the DC electrical pulse, this paper proposes a new EP system by applying continuous DC voltages to generate proper EP electric field strengths utilizing the shape change of the channel. The fabrication of chip and set-up of system are clearly described and simulations also carried out utilizing CFD-ACE to study the electric field strength distribution and the time span when fluid passes through different electric field strengths. The fabrication of the proposed EP system is quite simple and low-cost.
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Xu, Qing, Yu-Xing Li, Xiao-Ning Li, Jia-Bin Wang, Fan Yang, Yi Yang, and Tian-Ling Ren. "Simulation and experimental verification of silicon dioxide deposition by PECVD." Modern Physics Letters B 31, no. 06 (February 28, 2017): 1750055. http://dx.doi.org/10.1142/s0217984917500555.
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Deposition of silicon dioxide in high-density plasma is an important process in integrated circuit manufacturing. A software named CFD-ACE was used to simulate the mechanism of plasma in the chamber of plasma enhanced chemical vapor deposition (PECVD) system, and the evolution of the feature profile was simulated based on CFD-TOPO. Simulation and experiment of silicon dioxide that deposited in SiH4/N2O mixture by PECVD system was researched. The particle density, energy and angular distribution in the chamber were simulated and discussed. We also studied how the depth/width ratio affected the step coverage of the trench and analyzed the deposition rate of silicon dioxide on the feature scale. X-ray photoelectron spectroscopy (XPS) was used to analyze the elemental composition of thin films. Images of the feature profiles were taken by scanning electron microscope (SEM). The simulation results were in good agreement with experimental, which could guide the semiconductor device manufacture.
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Vakouftsi, E., C. Athanasiou, G. Marnellos, and Frank A. Coutelieris. "Theoretical Investigation of the Relation between the Output of a Methane Internal Reforming SOFC and the Composition of the Feedstream." Defect and Diffusion Forum 297-301 (April 2010): 838–43. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.838.
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It is a common point for the current fuel cell research to correlate the composition of the feedstream to the output of a Solid Oxide Fuel Cell (SOFC). In this direction, the detailed steady-state transport processes (i.e. the flow regime, the heat transfer, the mass and the charge transport) are mathematically described here. A new mesoscopic mathematical model has been developed through the relative differential equations along with the appropriate boundary conditions, which have been numerically integrated by using the commercially available software CFD-ACE+, in order to calculate the electricity produced by the fuel cell. It is found that the produced current density increases with CH4 percentage in the feeding mixture.
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Daryanto, Daryanto. "Comparative Study of Heat Transfer in Double Skin Facades on High-Rise Office Building in Jakarta." Applied Mechanics and Materials 170-173 (May 2012): 2751–55. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2751.
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Building envelope on high-rise office buildings have an important role of energy consumed. There are many methods and techniques that can be used to achieve this goal through energy efficiency for building envelope in the tropic area. The use of glass material becomes one of the alternatives that offer a more attractive appearance. Although the double skin facades (DSF) has been widely applied, but research on the thermal performance and behavior of the wind is still scarce for the tropics, so it is interesting to note related to energy conservation. To obtain a clear picture of the heat transfer and airflow, the research was conducted on the two office buildings with the same orientation and location but they were different on the building envelope. The study was conducted by the field measurements and simulation using CFD-ACE + software, to determine the performance of the heat transfer and behavior of airflow in the double skin facades. The results indicate that the role of wind on the design building envelope has an influence on the heat transfer and energy savings. Key words: wind, double skin facade, heat transfer, CFD, energy
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Bouris, D., R. Kubo, H. Hirata, and Y. Nakata. "Numerical Comparative Study of Compressor Rotor and Stator Blade Deposition Rates." Journal of Engineering for Gas Turbines and Power 124, no. 3 (June 19, 2002): 608–16. http://dx.doi.org/10.1115/1.1454113.
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Compressor fouling is generally accepted to be an important factor when monitoring the efficiency of an engine’s operation. However, there are not many studies related to the local fouling behavior of the individual components of the compressor. In the present paper, the CFD-ACE software package is used for the flow field calculation and the results are utilized to calculate the deposition rates on the blade surfaces of a conventional compressor stator and rotor. The deposition model takes into account the particle and surface material properties and the energy balance at the point of impact. A discussion is presented regarding the various mechanisms that produce the final deposition rate distribution and how the flow field and blade geometry affect it.
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Singhal, Ashok K., Mahesh M. Athavale, Huiying Li, and Yu Jiang. "Mathematical Basis and Validation of the Full Cavitation Model." Journal of Fluids Engineering 124, no. 3 (August 19, 2002): 617–24. http://dx.doi.org/10.1115/1.1486223.
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Cavitating flows entail phase change and hence very large and steep density variations in the low pressure regions. These are also very sensitive to: (a) the formation and transport of vapor bubbles, (b) the turbulent fluctuations of pressure and velocity, and (c) the magnitude of noncondensible gases, which are dissolved or ingested in the operating liquid. The presented cavitation model accounts for all these first-order effects, and thus is named as the “full cavitation model.” The phase-change rate expressions are derived from a reduced form of Rayleigh-Plesset equation for bubble dynamics. These rates depend upon local flow conditions (pressure, velocities, turbulence) as well as fluid properties (saturation pressure, densities, and surface tension). The rate expressions employ two empirical constants, which have been calibrated with experimental data covering a very wide range of flow conditions, and do not require adjustments for different problems. The model has been implemented in an advanced, commercial, general-purpose CFD code, CFD-ACE+. Final validation results are presented for flows over hydrofoils, submerged cylindrical bodies, and sharp-edged orifices. Suggestions for possible extensions of the model implementation, e.g., to nonisothermal flows, for ingestion and mixing of noncondensible gases, and for predictions of noise and surface damage are outlined.
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WU, YEONG-JEN, and WEI-HSIANG LAI. "THE SIMULATION OF THE PIEZOELECTRIC PRINT HEAD." Modern Physics Letters B 23, no. 03 (January 30, 2009): 441–44. http://dx.doi.org/10.1142/s0217984909018606.
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This paper investigates the flow dynamic behaviors with respect to different contact angle and frequency of the piezoelectric print head. Its geometric model is divided into three zones for easy description, i.e., channel zone, nozzle zone and ejection observing zone. The length, width and orifice diameter of the micro-channel are 2,000 µm, 400 µm and 30 µm, respectively. The moving wall is located on the top wall of the channel zone in order to obtain proper condition for single drop generation; we applied the numerical simulation by commercial CFD software – CFD-ACE+ 2004. The most important purpose of this study is to find out the optimal frequency to eject droplets periodically and control the volume of droplet ejection which may provide reference for experimental work later on. The results show that by fixing the frequency 20KHz, the nozzle contact angle is from 20 degree to 80 degree, the one droplet interval time value is less than 0.1% and the droplet size value is less than 1%. According to this result, we find that the effect of contact angle is not very important. Also for the frequency value from 50KHz to 100KHz, the first shot time is almost the same.
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Ge, Jie, Yi Yang, Xiao-Ning Li, and Tianling Ren. "Mechanisms for plasma etching of RRAM SiO2 with diblock copolymer selectivity." Modern Physics Letters B 28, no. 18 (July 11, 2014): 1450149. http://dx.doi.org/10.1142/s0217984914501498.
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To minimize the critical dimension of resistive switching random access memory (RRAM), good anisotropy and selectivity with diblock copolymer are required for silicon dioxide etching. Inductively coupled plasma (ICP) etcher using CHF 3/ H 2 mixture is used for effective etching of SiO 2. In this paper, a commercial software CFD-ACE+ was used to simulate reactor scale and feature scale model of SiO 2, diblock copolymer and Pt . Etch properties of SiO 2 at different chamber conditions were discussed. It was found that etch rate increased at the expense of selectivity as ICP power increased, which was the opposite trend for pressure. Selectivity and anisotropy are achieved at neutral to ion flux ratio 100:1. Moreover, the appropriate overetch time for SiO 2 layer to Pt layer was discussed.
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Lee, Kangsun, Choong Kim, and Kwang Oh. "Single-Layered Microfluidic Network-Based Combinatorial Dilution for Standard Simplex Lattice Design." Micromachines 9, no. 10 (September 25, 2018): 489. http://dx.doi.org/10.3390/mi9100489.
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In this paper, we presented a straightforward strategy to generate 15 combinations of three samples based on an experimental simplex lattice design using a single-layer microfluidic network. First, we investigated the performances of the plain structural and the groove structural combinatorial devices by computational simulation (CFD-ACE+). The simulated output concentrations were extremely close to the desirable values within an absolute error of less than 1%. Based on the simulated designs, polydimethylsiloxane (PDMS) devices were fabricated with soft lithography and tested with fluorescent dye (sodium salt). The mixing results for 15 combinations showed good performance, with an absolute error of less than 4%. We also investigated two liquid handling methods (bottom–up and top–down) for high-throughput screening and assay. The liquid-handling methods were successfully accomplished by adding the systematic structured groove sets on the mixing channels.
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Mayeed, M. S., A. Mian, G. W. Auner, and G. M. Newaz. "Accumulation of E. Coli Bacteria in Mini-Channel Flow." Journal of Biomechanical Engineering 128, no. 3 (November 18, 2005): 458–61. http://dx.doi.org/10.1115/1.2187049.
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The objective of this research is to design and optimize a mini/micro-channel based surface-accumulator of E. coli bacteria to be detected by acoustic wave biosensors. A computational approach has been carried out using the state of the art software, CFD-ACE with water as bacteria bearing fluid. E. coli bacteria have been modeled as random discrete particles tracked by solving the Lagrangian equations. The design challenges are to achieve low shear force (pico-N), high concentration at accumulation, and high enough Reynolds number to avoid bacteria swimming. A range of low Reynolds number (Re) has been considered along with the effects of particle boundary interactions, gravity, Saffman lift, etc. More than two orders of magnitude higher concentration at the accumulation than the inlet concentration, and lower shear force of less than pico-N have been achieved in the optimized designs.
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Lee, Jaewon, Choonghan Ryu, Sungwoo Lee, Donggeun Jung, Hyoungsub Kim, and Heeyeop Chae. "Carbon Nanotube Patterning with Capillary Micromolding of Catalyst." Journal of Nanoscience and Nanotechnology 7, no. 11 (November 1, 2007): 4174–79. http://dx.doi.org/10.1166/jnn.2007.18098.
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Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700∼800 °C by PECVD process using CH4 and Ar gas in a scale of ∼10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy.
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Braun, M. J., V. V. Kudriavtsev, B. M. Steinetz, and M. P. Proctor. "Two- and Three-Dimensional Numerical Experiments Representing Two Limiting Cases of an In-Line Pair of Finger Seal Components." International Journal of Rotating Machinery 9, no. 3 (2003): 171–79. http://dx.doi.org/10.1155/s1023621x03000162.
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The work presented here concerns the numerical development and simulation of the flow, pressure patterns, and motion of a pair of fingers arranged one behind the other and axially aligned in line. The fingers represent the basic elemental component of a finger seal and form a tight seal around the rotor. Yet their flexibility allows compliance with rotor motion and, in a passive-adaptive mode, compliance with the hydrodynamic forces induced by the flowing fluid. Although this article does not treat the actual staggered configuration of a finger seal, the in-line arrangement represents a first step toward that final goal. The numerical two-dimensional (axial-radial) and three-dimensional results presented herein were obtained using a commercial package (CFD-ACE+). Both models use an integrated numerical approach, which couples the hydrodynamic fluid model based on Navier-Stokes equations to the solid mechanics code that models the compliance of the fingers.
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Ghaya, H., R. Guizani, H. Mhiri, and P. Bournot. "CFD Study of the Effect of Geometrical Shape of Separation Blades on the Rotor Performance of an Annular Centrifugal Extractor (ACE)." Journal of Applied Fluid Mechanics 12, no. 4 (July 1, 2019): 1189–202. http://dx.doi.org/10.29252/jafm.12.04.29579.
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Kwon, Yong-Il. "A Study on the Improvement of ADPI and Ventilation Effectiveness in a Small Theater." International Journal of Air-Conditioning and Refrigeration 24, no. 03 (September 2016): 1650019. http://dx.doi.org/10.1142/s201013251650019x.
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In the air distribution design of a small theater, either a downward or an upward displacement ventilation is applied generally. The cool air is supplied from openings distributed over the ceiling and extracted beneath the seats for the downward flow and supplied from beneath the seats and extracted from the ceiling for the upward flow system. By the change of air exchange rate (ACH) produced by two divergent ventilation systems inside theater, thermal comfort and ventilation effectiveness around the seats show a different phenomenon. Thereby, it can be seen that the selection of the ventilation system is a significant factor in energy saving. CFD calculations for this study were performed to investigate the effects of various parameters (ADPI and ACE) of air distribution system applied in order to save the cooling energy. This paper focuses mainly on the effect of the varied volume flow rate depending on the ventilation system. The ventilation performances of the downward displacement system are compared quantitatively with the upward displacement system using the concept of the LMA of fresh air.
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Kito, Yasuo, Emi Makino, Kei Ikeda, Masao Nagakubo, and Shoichi Onda. "SiC HTCVD Simulation Modified by Sublimation Etching." Materials Science Forum 527-529 (October 2006): 107–10. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.107.
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High temperature chemical vapor deposition (HTCVD) simulations of silicon carbide (SiC) were demonstrated with experimental results. A vertical cylindrical reactor was used in an RF inductive heating furnace and the temperature was more than 2200. SiH4 and C3H8 were used as source gases and H2 as carrier gas. A gas phase reaction model from the literature was used on the condition that the gas phase reaction is a quasi-equilibrium state. It was found that the major species were Si, Si2C, SiC2 and C2H2 in the gas phase reaction model as well as in the thermodynamic equilibrium calculation. Sublimation etching was considered in the surface reaction rates by modifying partial pressures of species with equilibrium vapor pressures. CFD-ACE+ and MALT2 software packages were used in the present calculation. The sticking coefficients were determined by fitting the calculated growth rates to the experimental ones. The simulated growth rate in a different reactor is in good agreement with the experimental value, using the same sticking coefficients. The present simulation could be useful to design a new reactor and to find optimum conditions.
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Cheng, Ken Chuan, Kuan Yu Chen, A. Cheng Wang, and Yan Cherng Lin. "Study the Rheological Properties of Abrasive Gel with Various Passageways in Abrasive Flow Machining." Advanced Materials Research 126-128 (August 2010): 447–56. http://dx.doi.org/10.4028/www.scientific.net/amr.126-128.447.
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Abrasive flow machining (AFM) is a simple and efficient method to remove recasting layers making by wire electrical discharge machining (WEDM). However, conventional AFM methods have difficulty achieving uniform roughness of an axial distribution in circular hole polishing due to limited unitary axial motion of abrasive media. Therefore, this work develops mechanism designs for different passageways to obtain multiple flowing paths of abrasive medium, whose flowing behavior enhances polishing effectiveness by increasing the abrasive surface area and radial shear forces. The motion of the abrasive medium is studied by utilizing different mold cores, which mold shapes include the circular, hollow and helical passageway. The optimum design of the passageways is then verified using CFD-ACE+ software, numerical results indicate that passageway with six helices performed better in the uniform surface roughness than others’ do. Experimental results show that roughness deviation of six helices passageway of approximately 0.100 m Ra is significantly better than those on a circular passageway of around 0.1760 m Ra. Additionally, the six helices passageway is also superior to circular passageway in reducing roughness improvement rate (RIR) by roughly 87% compared with RIR 67.7% for the circular passageway.
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Chan, Tsung Hsing, Chiang Ho Cheng, An Shik Yang, and Li Yu Tseng. "A Novel Piezoelectric Valveless Micropump with an Integrated Diffuser/Nozzle Bulge Piece Design." Advanced Materials Research 74 (June 2009): 227–30. http://dx.doi.org/10.4028/www.scientific.net/amr.74.227.
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The current paper endeavors to present the design, fabrication, and test of a novel valveless piezoelectrically actuated micropump. The proposed micropump mainly comprises a stainless-steel structured chamber with a piezoelectric (PZT) diaphragm as a driving source to propel liquid stream under actuation. During tests, the micropump, operating at the frequency of 250 Hz and the voltage of 160 Vpp, engendered a mean water flowrate up to 0.779 ml/min. In the analysis, the computational fluid dynamics (CFD) software ACE+® was utilized to examine the time-varying flow phenomenon in a full-scale PZT micropump throughout an actuation cycle. The computational approach adopted the transient three-dimensional conservation equations of mass and momentum with the moving boundary specified to represent the movement of the diaphragm. At the frequency ranging from 150 to 250 Hz, the vortex pairs were evidently formed and thereby caused a relatively high pressure drop near the diffuser outlet inside the micropump chamber. Numerical experiments were also carried out by varying the opening angle of the diffuser/nozzle module within the range of 8°－12°, the angle setting of 8° can provide the best performance in term of the maximum pumping flowrate achieved.
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Wang, A. Cheng, Kuan Yu Chen, Ken Chuan Cheng, and H. H. Chiu. "Elucidating the Effects of Helical Passageways in Abrasive Flow Machining." Advanced Materials Research 264-265 (June 2011): 1862–67. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.1862.
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Conventional AFM have difficulty achieving uniform roughness of an axial distribution in circular hole polishing due to limited unitary axial motion of abrasive media. Therefore, this work develops mechanism designs for different passageways to obtain multiple flowing paths of an abrasive medium, whose flowing behavior enhances polishing effectiveness by increasing the abrasive surface area and radial shear forces. The motion of the abrasive medium is studied by utilizing the design of the mold cores, which mold shapes include the circular passageway and helical passageway. The optimum design of the different passageways is then verified using CFD-ACE+ numerical software. Analytical results indicate that the optimum design is the mechanism with a passageway of six helices. Furthermore, surface roughness measurements demonstrate the increase in uniformity and the roughness improvement rate (RIR). Experimental results for surface roughness indicate that roughness deviation of six helices passageway of approximately 0.1001 m Ra is significantly better than those on a circular passageway of around 0.1760 m Ra. Additionally, the six helices passageway is also superior to circular passageway in reducing roughness improvement rate (RIR) by roughly 85% compared with RIR 75% for the circular passageway.
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Tseng, L. Y., A. S. Yang, and J. C. Lin. "Study of a Crossflow over a Zero-Net-Mass-Flux Synthetic Jet Driven by a Vibrating Diaphragm." Journal of Mechanics 27, no. 4 (December 2011): 503–9. http://dx.doi.org/10.1017/jmech.2011.53.
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ABSTRACTMiniature synthetic jet actuators are low operating power, zero-net-mass-flux and very compact devices which have demonstrated their capability in modifying the subsonic flow characteristics for boundary layer flow control. In order to improve the design active flow control systems, the present study aims to examine the formation and interaction of unsteady flowfield of a synthetic jet with external crossflow. In view of a single synthetic jet emitting into a turbulent boundary layer crossflow via a circular orifice, the theoretical model utilized the transient three-dimensional conservation equations of mass and momentum for compressible, turbulent flows with a negligible temperature variation over the computational domain. The motion of a movable membrane plate was also treated as the moving boundary by prescribing the displacement on the plate surface. The predictions by the computational fluid dynamics (CFD) software ACE+®were compared with the measured transient phase-averaged velocities in literature for code validation. The predictions showed the time evolution of the large vortical structure originating from the jet orifice and its successive interaction with the crossflow to change the flow structure inside the boundary layer.
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Dang, Thanhtrung, Ngoctan Tran, and Jyh Tong Teng. "Numerical and Experimental Investigations on Heat Transfer Phenomena of an Aluminium Microchannel Heat Sink." Applied Mechanics and Materials 145 (December 2011): 129–33. http://dx.doi.org/10.4028/www.scientific.net/amm.145.129.
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The study was done both numerically and experimentally on the heat transfer behaviors of a microchannel heat sink. The solver of numerical simulations (CFD - ACE+software package) was developed by using the finite volume method. This numerical method was performed to simulate for an overall microchannel heat sink, including the channels, substrate, manifolds of channels as well as the covered top wall. Numerical results associated with such kinds of overall microchannel heat sinks are rarely seen in the literatures. For cases done in this study, a heat flux of 9.6 W/cm2was achieved for the microchannel heat sink having the inlet temperature of 25 °C and mass flow rate of 0.4 g/s with the uniform surface temperature of bottom wall of the substrate of 50 °C; besides, the maximum heat transfer effectiveness of this device reached 94.4%. Moreover, in this study, when the mass flow rate increases, the outlet temperature decreases; however, as the mass flow rate increases, the heat flux of this heat sink increases also. In addition, the results obtained from the numerical analyses were in good agreement with those obtained from the experiments as well as those from the literatures, with the maximum discrepancies of the heat fluxes estimated to be less than 6 %.
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Cho, Woong, Yong Jun Ko, Yoo Min Ahn, Joon Yong Yoon, and Nahm Gyoo Cho. "Surface Modification Effect of Wettability on the Performance of PDMS-Based Valveless Micropump." Key Engineering Materials 326-328 (December 2006): 297–300. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.297.
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Experimental investigation and numerical simulation on the effect of surface wettability on the performance of a polydimethylsiloxane (PDMS) based diffuser micropump are presented. A valveless micro membrane pump with piezoelectric actuation has been examined. Using a replica molding technique, the valveless micropump was made of PDMS on a Pyrex glass substrate. A thin piezoelectric (PZT) disc was used as an actuator. Poly vinyl alcohol (PVA) and octadecyltrichlorosilane (OTS) coatings, which make the coated surface hydrophilic and hydrophobic, respectively, were used to modify the surface wettability inside the pump. In our experiments, the contact angle of the PDMS surface changed from 96.6 o to 29.1 o and 99.6 o by PVA and OTS coatings, respectively, and the contact angle of glass changed from 33.2 o to 17.5 o and 141.8 o. A self-priming process was numerically simulated in a diffuser element using a computational fluid dynamics program (CFD-ACE+). The results show that fewer gas bubbles were created in the hydrophilic coated pump than in the hydrophobic coated one as time progressed. This agrees well with experimental observations. Steady-state flow rates of the micropump were measured. Compared to the non-coated pump, the flow rate increased slightly with the hydrophobic coating but decreased with the hydrophilic coating. We determine that surface wettability significantly affects the performance of a PDMS-based micropump.
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Klein, J. M., Y. Bultel, M. Pons, and P. Ozil. "Modeling of a Solid Oxide Fuel Cell Fueled by Methane: Analysis of Carbon Deposition." Journal of Fuel Cell Science and Technology 4, no. 4 (May 30, 2006): 425–34. http://dx.doi.org/10.1115/1.2759504.
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Natural gas appears to be a fuel of great interest for solid oxide fuel cell (SOFC) systems. It mainly consists of methane, which can be converted into hydrogen by direct internal reforming (DIR) within the SOFC anode. However, a major limitation to DIR is carbon formation within the ceramic layers at intermediate temperatures. This paper proposes a model solution using the CFD-ACE software package to simulate the behavior of a tubular SOFC. A detailed thermodynamic analysis is carried out to predict the boundary of carbon formation for SOFCs fueled by methane. Thermodynamic equilibrium calculations that take into account Boudouard and methane cracking reactions allow us to investigate the occurrence of carbon formation. This possibility is discussed from the values of driving forces for carbon deposition defined as α=PCO2∕(KBPCO2) and β=PH22∕(KCPCH4), from the equilibrium constants KB and KC of the Boudouard and cracking reactions, and from the partial pressure Pi of species i. Simulations allow the calculation of the distributions of partial pressures for all the gas species (CH4, H2, CO, CO2, and H2O), current densities, and potentials of both electronic and ionic phases within the anode part (i.e., gas channel and Cermet anode). Finally, a mapping of α and β values enables us to predict the predominant zones where carbon formation is favorable (α or β<1) or unfavorable (α or β>1) according to the calculation based on thermodynamic equilibrium. With regard to the values of these different coefficients, we can say that a carbon formation can be supposed for temperature less than 800°C and for ratios xH2O∕xCH4 smaller than 1.
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Huang, Cheng-Hung, and Chih-Yang Kuo. "A Nonlinear Inverse Design Problem for a Pipe Type Heat Exchanger Equipped with Internal Z-Shape Lateral Fins and Ribs." Energies 13, no. 23 (December 4, 2020): 6424. http://dx.doi.org/10.3390/en13236424.
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A non-linear three-dimensional inverse shape design problem was investigated for a pipe type heat exchanger to estimate the design variables of continuous lateral ribs on internal Z-shape lateral fins for maximum thermal performance factor η. The design variables were considered as the positions, heights, and number of ribs while the physical properties of air were considered as a polynomial function of temperature; this makes the problem non-linear. The direct problem was solved using software package CFD-ACE+, and the Levenberg–Marquardt method (LMM) was utilized as the optimization tool because it has been proven to be a powerful algorithm for solving inverse problems. Z-shape lateral fins were found to be the best thermal performance among Z-shape, S-shape, and V-shape lateral fins. The objective of this study was to include continuous lateral ribs to Z-shape lateral fins to further improve η. Firstly, the numerical solutions of direct problem were solved using both polynomial and constant air properties and then compared with the corrected solutions to verify the necessity for using polynomial air properties. Then, four design cases, A, B, C and D, based on various design variables were conducted numerically, and the resultant η values were computed and compared. The results revealed that considering continuous lateral ribs on the surface of Z-shape lateral fins can indeed improve η value at the design working condition Re = 5000. η values of designs A, B and C were approximately 13% higher than that for Z-shape lateral fins, however, when the rib numbers were increased, i.e., design D, the value of η became only 11.5 % higher. This implies that more ribs will not guarantee higher η value.
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Hayashi, Ken, Koike Takuji, Sho Kanzaki, and Kaoru Ogawa. "R441 – 3D Finite Element Model for Perilymphatic Fistula." Otolaryngology–Head and Neck Surgery 139, no. 2_suppl (August 2008): P192. http://dx.doi.org/10.1016/j.otohns.2008.05.597.
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Problem To investigate the relationship between the intrusion of the air bubble into the scala vestibli and hearing loss at low frequencies. Methods The effect of intrusion of an air bubble into the scala vestibuli on auditory activity was analyzed based on clinical data and using a three-dimensional finite element (FE) model of the human cochlea. The FE model consists of the stapes, the stapedial annular ligament, the oval window, vestibule, lymph, basilar membrane, osseous spiral lamina, and the cochlear aqueduct. An air bubble in the scala vestibuli was modeled as a small fistula opened on the bony wall of the cochlea. The induced vibration of the lymph and the basilar membrane was calculated by changing the position of the air bubble using CFD-ACE software. Results A traversing wave was generated on the basilar membrane of the intact cochlear model by vibrating the stapes. Even if the air bubble existed in the scala vestibuli, the traversing wave was also generated. When the air bubble existed at the second turn of the cochlea, an envelope of the traversing wave had a notch at the portion where the air bubble existed. The ratio of the maximum amplitude of the basilar membrane in the cochlea with the air bubble to that in the intact cochlea decreased with decreasing frequency. The maximum amplitude of the traversing wave in the cochlea with the air bubble was smaller than that in the intact cochlea by 20 dB at 500 Hz. This result is consistent with clinical data. Conclusion Our results suggest that the intrusion of an air bubble into the scala vestibuli causes hearing loss at low frequencies. Significance The removal of air bubbles into the scala vestibli is needed for hearing improvement.
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Krzaczek, M., and J. Tejchman. "Numerical Investigations of Effect of Indoor Air Quality on Thermal Comfort in Residential Buildings." Archives of Civil Engineering 60, no. 1 (March 1, 2014): 91–121. http://dx.doi.org/10.2478/ace-2014-0005.
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Abstract The influence of the CO2 concentration in a local air zone in naturally ventilated residential houses on the residents’ behaviour was numerically investigated. A numerical two-dimensional CFD model of the indoor zone based on experiments performed by the authors was used. Different resident locations in the fluid domain and different inlet velocities imposed by wind were considered in simulations. The overall thermal comfort and IAQ indices were also calculated. The investigations results show that in contrast to the overall air quality, the local CO2 was strongly dependent upon the resident location, fresh air inlet velocity and ventilation system type.
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Ding, X. R., Y. Y. Guo, and Y. Y. Chen. "Design and Simulation of an Air Conditioning Project in a Hospital Based on Computational Fluid Dynamics." Archives of Civil Engineering 63, no. 2 (June 27, 2017): 23–38. http://dx.doi.org/10.1515/ace-2017-0014.
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AbstractThis study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primaiy humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
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Jayasree, T. K., B. S. Jinshah, V. Lakshmi Visakha, and Tadepalli Srinivas. "ASSESSMENT OF AIR CHANGE EFFECTIVENESS AND THERMAL COMFORT IN A NATURALLY VENTILATED KITCHEN WITH INSECT-PROOF SCREEN USING CFD." Journal of Green Building 16, no. 3 (June 1, 2021): 37–56. http://dx.doi.org/10.3992/jgb.16.3.37.
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ABSTRACT Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation. The opening of exterior windows for ventilation allows the entry of insects along with the breeze. As a remedy, occupants install insect-proof screens on windows resulting in reduced airflow into the interior. This study attempts to evaluate the air change effectiveness and thermal comfort in a residential kitchen with insect-proof screens. A kitchen with insect-proof screens on the windows is compared with a case without insect-proof screens. Numerical simulation was conducted using ANSYS Fluent 2019 R2. The insect-proof screen is modelled as a porous media. The air velocity and temperature measurements were validated by measurements in a real scenario. The presence of insect-proof screens reduced the air velocity inside the space by 82%. However, the airflow pattern in the case with screens was more uniformly distributed. The mean age of the air was considerably higher in the case with insect-proof screens, which in turn resulted in a reduced ACE. The presence of an insect-proof screen resulted in a Predicted Mean Vote (PMV) of 2.79 indicating a ‘hot’ sensation, whereas in the other case, the comfort vote is only 1.93 indicating a ‘warm’ sensation. The presence of insect-proof screens on windows reduced the air velocity and ventilation efficiency, contributing to increased thermal discomfort in the kitchen.
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"CFD-ACE+." KSFM Journal of Fluid Machinery 7, no. 5 (October 1, 2004): 68–72. http://dx.doi.org/10.5293/kfma.2004.7.5.068.
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"Modeling of SiC CVD Epitaxial Growth using CFD-ACE+." ECS Meeting Abstracts, 2012. http://dx.doi.org/10.1149/ma2012-02/30/2527.
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Qiu, Yifan, and M. M. Khonsari. "Thermohydrodynamic Analysis of Spiral Groove Mechanical Face Seal for Liquid Applications." Journal of Tribology 134, no. 2 (April 1, 2012). http://dx.doi.org/10.1115/1.4006063.
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In this study, a three-dimensional thermohydrodynamic (THD) CFD model is developed to study the characteristics of an inward pumping spiral groove mechanical seal pair using a commercial CFD software CFD-ACE + . The model is capable of predicting the temperature distribution and pressure distribution of the seal pair. Based on the CFD model, a parametric study is conducted to evaluate the performance of the seal. It is found that thermal behavior plays an important role in the overall performance of a seal. The spiral groove parameter can be optimized to achieve desired performance. The optimization is dependent on the application requirement of the seal.
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Huang, Cheng-Hung, and Wei-Lun Chang. "An Inverse Problem in Estimating the Volumetric Heat Generation for a Three-Dimensional Encapsulated Chip." Journal of Electronic Packaging 132, no. 1 (March 1, 2010). http://dx.doi.org/10.1115/1.4000720.
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A three-dimensional inverse heat conduction problem is solved in the present study by using the conjugate gradient method (CGM) and the general-purpose commercial code CFD−ACE+ to estimate the strength of the unknown heat generation for an encapsulated chip in a three-dimensional irregular domain. The advantage of calling CFD−ACE+ code as a subroutine in the present inverse calculation lies in that many difficult but practical 3D inverse problem can be solved under this construction since the general-purpose commercial code has the ability to solve the direct problem easily. The results obtained by using the CGM to solve this 3D inverse problem are justified based on the numerical experiments using the simulated exact and inexact measurements. It is concluded that reliable heat generation can be estimated by the present inverse algorithm.
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"Optimization of Parameters to Improve Ventilationin Underground Mine Working using CFD." International Journal of Recent Technology and Engineering 8, no. 4 (November 30, 2019): 12436–41. http://dx.doi.org/10.35940/ijrte.d8968.118419.
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Intundergroundtmine,tittistverytimportantttotmainta intfreshtandtsufficienttairtintunventilatedareasttotmaintainsafew orkingenvironmenttfortworkers.tTotstudytthetbehaviourtoftairflo wintundergroundtmine,tatT shaped crosscuttregiontoftBordandt Pillarmining ist considered forsimulation tint twot differentcases:twithouttandtwithtthintbratticetpositioningtattcross cutregion.tBratticetistcostteffectiveventilationcontroltdevicettodefl ectairtintotunventilatedareasintundergroundmine.Theultimatetob jectiveisttotfindtthetbestlocationtanddimensionofbratticetacrosstt hetcrosscuttregiontbytwhichtonetcantgetmaximumtvelocitytattdea dtend.tInthistthesis,tatcomputationalfluiddynamicst(CFD)tandtop timizationtalgorithmstareconsideredfortmaximizingtthetairtflowta ttthetdeadtendtbyplacingtatbratticetattoptimumlocation.tTwodiffe rentoptimizationtalgorithms:tmultiobjectivetgenetictalgorithm(MOGA)andtnonlinearprogrammingtofquadraticLagrangian(NLPQL)toptimizatio nttechniquestweretusedtintthisstudy.ANSYStFLUENTtsoftwareti stusedtforCFDtmodelingtat Tshapedtcrosscuttregiontandcomputestthetsimulationtresulttofairtf lowtvelocitytattdeadtend.tOptimizationttechniquesareusedforttoop timizetfourtinputtparameters;tbratticetpositiontverticalandhorizo ntaltfromtthewalltoftcrosscuttregiontandtwidthtandlengthtoftbratt ice.Thetobjectivestfortoptimizationstaretomaximizetthetvelocitytat tdeadtendtandtminimizetthetpressuredroptintcrosscuttregion.Com parisonistcarriedtouttbetweencrosscuttregiontwithouttandtwithtat thinbratticetusingoptimizationttechniquestandtfoundtthetbesttlocationtanddimensionoftbra ttice.tTotincreasethetairtflowtvelocitytattdeadtendincrease tthetsafetworkingtfortworkerstandtsupplyadequateairtatworkingtf ace
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Chen, Chiun-Hsun, Chang-Hsin Chen, and Tang-Yuan Chen. "The Numerical Study of Geometric Influence of Flow Channel Patterns on Performance of Proton Exchange Membrane Fuel Cells." Journal of Fuel Cell Science and Technology 9, no. 2 (March 19, 2012). http://dx.doi.org/10.1115/1.4005615.
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This study numerically investigates how the geometry of flow pattern influences performance of proton exchange membrane fuel cell (PEMFC), and analyzes how these parameters lead to different distributions of model variables. The investigation focuses on the impact of different bend angle and width of serpentine flow channels and tests how they improve the performance. Three-dimensional simulations are carried out with a steady, two-phase, multicomponent and electrochemical model, using CFD-ACE+, the commercial CFD code. Through simulation with various bend angles and widths, the results show that the combination of 60 deg and 120 deg for flow pattern achieves the highest performance at low operating voltage regime, and flow pattern with wider bend width also produces more current at low operating voltages. Plots of current density indicate that high current density locates at the bending areas of the channels. Therefore, the output current densities of each pattern are improved from the change of bend angle and width.
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Lowry, S., J. C. Sheu, Robert Stewart, and Robert Parkhill. "Numerical Simulation of Laser Induced Substrate Heating for Direct Write of Mesoscopic Integrated Conformal Electronics (MICE)." MRS Proceedings 624 (2000). http://dx.doi.org/10.1557/proc-624-243.
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ABSTRACTA numerical tool is developed to simulate the optical and thermal interactions of selected lasers with precursors and substrates in support of the emerging technology for the direct write of Mesoscopic Integrated Conformal Electronics (MICE). The code couples the Discrete Ordinate Method (DOM) radiation model with the multi-physics computation fluid dynamics code CFD-ACE to predict the conductive and radiative heat transport in the processThis paper provides a brief overview of the numerical model. Selected simulations are presented including comparison with empirical data. The capabilities, limitations, and potential applications of the model with respect to MICE are discussed. Future model enhancements are proposed
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McCall, Sonya D., and Klaus J. Bachmann. "Three-Dimensional Modeling of the High Pressure Organometallic Chemical Vapor Deposition of InN using Trimethylindium and Ammonia." MRS Proceedings 693 (2001). http://dx.doi.org/10.1557/proc-693-i3.13.1.
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AbstractA physico-chemical model of the High Pressure Organometallic Chemical Vapor Deposition (HPOMCVD) process that describes three dimensional transport phenomena as well as gas-phase and surface reactions underlying the growth of compound semiconductors is presented. A reduced-order model of the Organometallic Chemical Vapor Deposition of indium nitride (InN) from trimethylindium In(CH3)3 or TMI and ammonia (NH3) at elevated pressures has been developed and tested using the computational fluid dynamics code, CFD-ACE+. The model describes the flow dynamics coupled to chemical reactions and transport in the flow channel of the Compact Hard Shell Reactor, as a function of substrate temperature, total pressure and centerline flow velocity.
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Yakovlev, E. V., R. A. Talalaev, S. Yu Karpov, Yu A. Shpolyanskiy, Yu N. Makarov, and S. A. Lowry. "Comprehensive Reactor-Scale Modeling of III-V Ternary Compound Growth by Movpe." MRS Proceedings 616 (2000). http://dx.doi.org/10.1557/proc-616-153.
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AbstractA novel quasi-thermodynamic approach is suggested to simulate surface chemistry in III-V compound MOVPE. Blocking of free adsorption sites by methyl radicals is considered as the mechanism limiting the growth rate at low temperatures. This assumption has provided a good reproduction of experimental data on GaAs MOVPE in various types of reactor. The commercial computational fluid dynamics software CFD-ACE™ has been used to perform a detailed threedimensional modeling of AlGaAs and InGaP deposition in an AIX-200 horizontal reactor. The surface model has been incorporated into the code to obtain the growth rate and layer composition distributions over the substrate. Modeling results demonstrate a reasonable agreement with experimental data.
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Song, Hongjun, and Dawn J. Bennett. "An Analytical Method for Dielectrophoresis and Traveling Wave Dielectrophoresis Generated by an n-Phase Interdigitated Parallel Electrode Array." Journal of Fluids Engineering 130, no. 8 (August 1, 2008). http://dx.doi.org/10.1115/1.2956610.
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In this paper, we present an analytical method for solving the electric potential equation with the exact boundary condition. We analyze the dielectrophoresis (DEP) force with an n-phase ac electric field periodically applied on an interdigitated parallel electrode array. We compare our analytical solution with the numerical results obtained using the commercial software CFD-ACE. This software verifies that our analytical method is correct for solving the problem. In addition, we compare the analytical solutions obtained using the exact boundary conditions and the approximate boundary conditions. The comparison shows that the analytical solution with the exact boundary condition gives a more accurate analysis for DEP and traveling wave DEP forces. The DEP forces of latex beads are also investigated with different phase arrays for (n=2,3,4,5,6).
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Mazumder, Sandip, and Michael Grimm. "Numerical Investigation of Radiation Effects in Monolithic Catalytic Combustion Reactors." International Journal of Chemical Reactor Engineering 9, no. 1 (June 5, 2011). http://dx.doi.org/10.1515/1542-6580.2523.
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In modeling catalytic combustion in a monolithic catalytic converter, it is generally assumed that the gas within the individual monolith channels does not interfere with thermal radiation. To date, no quantitative study has been undertaken to validate this assumption. Past studies for carbon monoxide combustion also appear to indicate that the emissivity of the washcoat has little effect on the thermal radiation field. In order to investigate these two issues, methane-air combustion on platinum is modeled inside a single channel of a monolith using a detailed surface reaction mechanism comprised of 24 reactions between 19 species. Radiation transport is modeled using the Discrete Ordinates Method and a gray formulation. Planck-mean absorption coefficients of the gases, calculated from the HITEMP and HITRAN databases, are used to investigate participating medium effects. All calculations were performed using the commercial CFD code, CFD-ACE+, supplemented by user-subroutines for calculating the radiative properties of the gas mixture. Results show that the conversion percentages and temperature distributions are unaltered by the inclusion of participating medium radiation effects, verifying the commonly held belief, stated earlier. However, in strong contrast with carbon monoxide combustion, the emissivity of the washcoat was found to significantly affect flammability limits in the case of methane combustionthe flame being hotter and more stable for smaller values of emissivity.