design optimization environments are used for electric vehicles and other traction applications to arrive at efficient motor drives. Typically, the environment includes characterization modules that involve the use of...
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design optimization environments are used for electric vehicles and other traction applications to arrive at efficient motor drives. Typically, the environment includes characterization modules that involve the use of Electromagnetic Finite Element and State-Space models that require large number of iterations and computational time. This work proposes the utilization of a taguchi orthogonal arrays method in conjunction with a Particle Swarm Optimization search algorithm to reduce computational time needed in the design optimization of electric motors for traction applications. The effectiveness of the taguchi method in conjunction with the optimization environment is demonstrated in a case study involving a prototype of a Synchronous Reluctance Motor drive system.
This paper develops a method of knowledge-aided clutter suppression for subsurface radar imaging by crafting the power spectrum of the transmit waveform. The power spectrum is optimized to enhance the signal-to-clutte...
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ISBN:
(纸本)9781728168135
This paper develops a method of knowledge-aided clutter suppression for subsurface radar imaging by crafting the power spectrum of the transmit waveform. The power spectrum is optimized to enhance the signal-to-clutter-ratio (SCR) by target matched illumination for suppressing transmit power in dominant clutter frequencies. This approach is extended to radar imaging for the enhancment of the overall 2-dimensional target reflectivity function. By modelling the received signal as the output of an LTI filter, the channel capacity can be maximized. An algorithm is developed using taguchi techniques to optimized the spectrum and thus reduce the clutter in radar images. Particle swarm optimization (PSO) is extended to waveform design for comparison. The optimization objective function is the mutual information between the received signal and the target response conditioned upon a transmit waveform. The PSO and taguchi algorithms are seen to converge quickly to a waveform that maximizes the SCR. The radar imagery is formed using the newly optimized waveforms to test the methodology by the coherent addition of simulated and distributed target and clutter responses. The SCR is used as a performance metric. The results show that transmitting a waveform tailored to the frequency response of the target and clutter improve the SCR and mutual information over a conventional linearly frequency modulated waveform.
High performing hemodialyzers membranes such as high flux membranes, high cut-off membranes and medium cut-off membranes are always at research interest due to their better efficiency than conventional membranes. Thes...
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High performing hemodialyzers membranes such as high flux membranes, high cut-off membranes and medium cut-off membranes are always at research interest due to their better efficiency than conventional membranes. These membranes provide greater toxin clearance, however retention of essential solutes in a preferable way are still under study. This paper aims at the design of high performing membrane to study the role of its parameters in solute removal and its capability of holding back important molecules. One of the most effective design of experiments (DOE) tool, namely taguchi algorithm was used for the formation of fractional factorial design of parameters. The simulation results were benchmarked with that of experimental data from literature and with manufacturers data sheets. Once the benchmarking was done, the error quantification and significance of each design were analysed using statistical method, Analysis of Variance (ANOVA) testing. The most relevant parameters that helped in better clearance in these membranes were thus identified and substantial conclusions were drawn which can be used in the future for designing optimal dialyzer designs. Results shows that clinically used dialyzer membranes such as RevaclearMax and FxCorDiax series on modelling using COMSOL Multiphysics with a blood flow rate of 400 ml/min and dialysate flow of 500 ml/min showed better urea clearance rate of above 300 indicating that the membranes thus designed was superior to the conventional high flux membranes that have a clearance rate of 297 of less for the exact same functional, geometrical, and parametric conditions. The model replication and thus validation of the design helped in understanding the influence of various parameters in toxin clearance. These parameters can be further investigated, and optimal models can be delivered with more of clinical examinations and trials.
Characterization modules in electric machines and drives design optimization environments typically involve the use of electromagnetic finite element-state space models that require large number of iterations and comp...
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Characterization modules in electric machines and drives design optimization environments typically involve the use of electromagnetic finite element-state space models that require large number of iterations and computational time. It is shown in this work that the utilization of a taguchi orthogonal arrays method in conjunction with a particle swarm optimization (PSO), search algorithm in a design optimization case study of a synchronous reluctance motor (SynRM) drive, resulted in about 80% reduction of computational time.
Fouling formation in gas dehydration units is performed mainly by gradual accumulation of sulfur-containing compounds and its corrosion products in glycol streams. High concentrations of iron-sulfur species in glycol ...
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Fouling formation in gas dehydration units is performed mainly by gradual accumulation of sulfur-containing compounds and its corrosion products in glycol streams. High concentrations of iron-sulfur species in glycol media increase the fouling propensity on the tube surfaces of heat exchangers. Therefore, the factors affecting the fouling formation and their ranks were determined in a pilot plant gas dehydration unit. Then, the morphology and composition of the fouling layers were studied by qualitative and quantitative XRD patterns. The results revealed that among studied parameters, the concentration of dissolved iron in glycolic media is the main factor responsible for the formation of iron-sulfide deposits. Moreover, it was showed that non-stoichiometric pyrrhotite polytypes 4C, 5C and 6C are the base components of fouling scales deposited on the surface of heat exchangers. Distribution of iron-based species was also determined in the cross-section of a typical heat exchanger and the results showed that the deposited layers are consisted of hydrocarbon residues and pyrrhotite polytypes. Over the time, the pyrrhotite polytypes in deposited layers are covered by paraffin residues absorbed by TEG phase from the natural gas stream.
Hydrofoil, as the basic shape of the fluid blade, is widely used in fluid transport and energy conversion. However, friction resistance and pressure differential resistance are generated in the hydrofoil flow process,...
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Hydrofoil, as the basic shape of the fluid blade, is widely used in fluid transport and energy conversion. However, friction resistance and pressure differential resistance are generated in the hydrofoil flow process, resulting in substantial energy consumption and negatively affecting the economy. On this basis, we propose two drag-reducing structures based on Clark-Y hydrofoil. In the design process of the jet structure, we considered the bionic jet velocity, jet angle and jet structure position as the design parameters and obtained the optimal jet structure by using taguchi method. Finally, the two schemes (Clark-Yori and Clark-Yopt) are numerically simulated using large eddy simulation. Results show that when U jet = 1.44 m/s, theta = 3 degrees and x = 18.6 mm, the jet structure can play a significant drag reduction effect. Compared with Clark-Yori, the drag coefficient of Clark-Yopt is reduced by 26.5%, and the lift drag ratio is increased by 16.4%. Compared with Clark-Yori, Clark-Yopt can reduce the wall shear stress of the leading edge of the hydrofoil, thereby diminishing the frictional resistance. Meanwhile, the jet structure can effectively balance the area of the low-pressure region on the suction side of the hydrofoil, significantly reducing the pressure differential resistance. Clark-Yopt can accelerate the vortex collapse that decreases turbulence intensity and turbulence resistance. Moreover, it can effectively block the near-wall reflux of hydrofoil and reduce the internal friction between the reflux and the main flow.
Nowadays, microchannels have been widely utilized in various multidisciplinary fields, and as a consequence, some new and different requirements for microchannels in the process of practical application are required, ...
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Nowadays, microchannels have been widely utilized in various multidisciplinary fields, and as a consequence, some new and different requirements for microchannels in the process of practical application are required, such as structure, working fluid, and operating conditions, etc. This article reviews the current research achievement of microchannels, as well as the thermodynamic research on microchannels with different structures in the past five years, but mainly focuses on the numerical methods. The purpose of this review article aims to summarize a comprehensive overview of the latest developments of numerical methods in microchannel heat sinks, as well as to provide a useful benchmark for future research. The present article reviews straightforward on the most commonly used numerical methods for solving governing equations and optimizing data, including conventional computational fluid dynamics (CFD) simulation methods, molecular dynamics simulation (MDS), Lattice Boltzmann methods (LBM), direct simulation Monte Carlo (DSMC), and other techniques such as machine learning (ML) approach, artificial neural network (ANN) method, genetic algorithm (GA), taguchi algorithm (TA), as well as optimisation methods. This review will not only help to understand the physical mechanism of microchannels in different application fields but also help to fill in the gaps in related research and provide research methods for future numerical studies.
This paper built a finite element model of the Halbach permanent magnet motor, whose accuracy was verified by comparing the output phase back-electromotive force of the model with that of the prototype motor. Keeping ...
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This paper built a finite element model of the Halbach permanent magnet motor, whose accuracy was verified by comparing the output phase back-electromotive force of the model with that of the prototype motor. Keeping other parameters constant as far as possible, we investigated five variables one by one to find out the law how these variables affect air gap magnetic flux, which is a basis for further optimization research. After a new variable named Cost constructed to reflect the distortion ratio of air gap magnetic flux, this paper performed some optimization experiments by studying five parameters of the motor using taguchi algorithm, Genetic algorithm and Pattern Search algorithm. On the basis of summarizing the advantages and disadvantages of these algorithms, we proposed two kinds of novel hybrid optimization algorithms, which are named as taguchi-Pattern Search algorithm and Genetic-Pattern Search algorithm, and proved the validity and practicability by experiments and finite element calculations.
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