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Design and Experimentation of a 1 MW Horizontal Axis Wind Turbine

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Journal of Power and Energy Engineering 2014年第1期2卷 9-16页

作者： miguel toledo velázquez Marcelino Vega Del Carmen Juan Abugaber Francis Luis A. Moreno Pacheco Guilibaldo Tolentino Eslava Instituto Politécnico Nacional Laboratorio de Ingeniería Térmica e Hidráulica Aplicada México D.F. México Instituto Politécnico Nacional Laboratorio de Ingeniería Térmica e Hidráulica Aplicada México D.F. México.

In this work was carried out the aerodynamics design of a 1 MW horizontal axis wind turbine by using blade element momentum theory (BEM). The generated design was scaled and built for testing purposes in the discharge of an axial flow fan of 80 cm in diameter. Strip theory was used for the aerodynamic performance evaluation. In the numerical calculations was conducted a comparative analysis of the performance curves adding increasingly correction factors to the original equation of ideal flow to reduce the error regarding real operating values got by the experimental tests. Correction factors introduced in the ideal flow equation were the tip loss factor and drag coefficient. BEM results showed good approximation using experimental data for the tip speed ratio less than design. The best approximation of the power coefficient calculation was for tip speed ratio less than 6. BEM method is a tool for practical calculation and can be used for the design and evaluation of wind turbines when the flow rate is not too turbulent and radial velocity components are negligible.

关键词： Wind Turbine Design BET BEM Tip Speed Ratio Tip Lost Factor HAWT

Energy and Exergy Analysis of Moist Air for Application in Power Plants

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Energy and Power Engineering 2011年第3期3卷 376-381页

作者： Martín Salazar-Pereyra miguel toledo-velázquez G. Tolentino Eslava Raúl Lugo-Leyte Celerino Reséndiz Rosas Tecnológico de Estudios Superiores de Ecatepec División de Ingeniería Mecatrónica e Industrial Posgrado en Ciencias en Ingeniería Mecatrónica Instituto Politécnico Nacional Escuela Superior de Ingeniería Mecánica y Eléctrica Sección de Estudios de Po

In this study an energy and exergy analysis is made of moist air, it is used the psychometrics charts. A Visual Basic program is used to generate psychometrics charts. These charts are used to analyze the air thermodynamic behavior, considering the environmental variations, pressure, temperature and relative humidity. Also, the available energy in the cooling processes at constant enthalpy, humidification at constant temperature and heating with constant relative humidity is analyzed. For example, we obtained that the enthalpy and exergy in a thermodynamic state, with conditions, Patm = 1.013 bar, Tatm = 25oC and Φatm=50%, are h = 50.56 kJ/kga and ε =11.5 kJ/kga;and for Patm= 0.77 bar to the same conditions of Tatm and Φatm, the enthalpy and exergy increases in a 14% and 20%, respectively.

关键词： Energy Analysis Exergy Analysis Moist Air Power Plants

The Design of Heat Exchangers

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Engineering（科研） 2011年第9期3卷 911-920页

作者： Arturo Reyes-León miguel toledo velázquez Pedro Quinto-Diez Florencio Sánchez-Silva Juan Abugaber-Francis Celerino Reséndiz-Rosas 不详

A relation between heat transferred and energy loss, for turbulent flow. In different tube arrangements, is made. The conditions are determined which decide the dimensions and velocities for a heat exchanger. Also, a reference to the economic dimensioning of heat exchangers is presented. In this study, the conditions which a heat exchanger must satisfy represent the best balance between the amounts of material employed. The investigation is restricted to the case of turbulent flow.

关键词： Heat Changers Energy Loss Economic Dimensioning Counterflow Crossflow and Parallelflow

The Density and Momentum Distributions of 2-Dimensional Transonic Flow in an LP-Steam Turbine

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Energy and Power Engineering 2012年第5期4卷 365-371页

作者： Aldo Antonio Rueda Martínez Fernando Rueda Martínez miguel toledo velázquez Florencio Sánchez Silva Ignacio Carvajal Mariscal Juan Abugaber Francis Researching and Graduate Section Applied Hydraulics and Thermal Engineering Laboratory

Within turbine blade rows, particularly for cascades of high deflection angle, cross-channel gradients of steam properties may be appreciable. To determine the effects on spontaneous condensation of gradients of supersaturation normal to streamlines, the conservation equations can be incorporated in a two dimensional calculation procedure. With the help of program FORTRAN 90 a developed computational program of calculations is accomplished, whose results are communicated to the pressure and Mach number distribution, direction of flow and streamlines in the field and the drops distribution in the outlet of the stator blade mesh. The procedure contains a program section, which avoids difficulties in the strongly curved profile of the leading and trailing edge by a developed computational mesh construction.

关键词： Steam Turbines Nucleation Two Phase Flow Erosion

Delaware Method Improvement for the Shell and Tubes Heat Exchanger Design

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Engineering（科研） 2014年第4期6卷 193-201页

作者： miguel toledo-velázquez Pedro Quinto-Diez Juan C. Alzelmetti-Zaragoza Sergio R. Galvan Juan Abugaber-Francis Arturo Reyes-León Applied Thermal and Hydraulic Engineering Laboratory SEPI-ESIME-IPN Professional Unit “Adolfo Lopez Mateos” México DF México Faculty of Mechanical Electrical Engineering Universidad Veracruzana Veracruz México Faculty of Mechanical Engineering Universidad Michoacana de Sán Nicolas de Hidalgo Edifice H University City Santiago Tapia 403 Col. Centro Morelia Michoacán México

In this paper the Delaware Method published in 1963 is analyzed and upgraded with using correction factors which take into account the undesirable currents of the mean flow. However, this method presents graphically these correction factors which imply an impediment to fulfill the software calculations. Thus, the equations corresponding to the correction factor equations and a Fortran 77 numerical program were established. This system is given to explore different design alternatives in order to find the optimal solution to each proposed problem. The results of this work was a simple software that can perform calculations with the introduction of parameters depending only on the geometry of the heat exchanger, i.e., geometry, temperature and fluid characteristics eliminating the human errors and increasing the calculations speed and accuracy.

关键词： Delaware Method Flow Correction Factor Heat Exchanger

Computational Analysis of Flow Field on the Propulsion Nozzle of a Micro-Turbojet Engine

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Engineering（科研） 2012年第1期4卷 1-5页

作者： Jorge Luis Garrido-Téllez miguel toledo-velázquez Samuel Alcántara-Montes José ángel L. Ortega-Herrera Arturo Reyes-León 不详

The purpose of this paper is to analyze the flow field on the propulsion nozzle of a micro-turbojet engine in function of the velocity. The 2D axisymmetric numerical simulation was made by using commercial software FLUENT?. A micro-turbojet engine was also employed for this study and it has the following characteristics: 100 N thrust, 130,000 rpm, mass flow rate 0.2650 kg/s, weight 1.2 kg. This engine is operating in Mexico city under the following conditions: P0, 78,000 Pa T0, 300 K, πc, 2.1 and a turbine entry temperature of 1000 K;it is considered that the nozzle is not choked. For this study, the viscous standard k- model, a semi-empirical model based on transport model equations for the turbulent kinetic energy (k) and its dissipation rate, is used. The transport model equation for k is derived from the ex-act equation, while the transport model equation for is obtained by using physical reasoning and bears resemblance to its mathematically exact counterpart. The employed grids are structured and the boundary conditions are obtained from a thermodynamic analysis. The results that are obtained show an increment of the velocity of 6.25% to the exit propulsion nozzle.

关键词： Propulsion Nozzle Model Transport Equation Numerical Simulation Small Micro Turbine

Numerical Analysis of the Natural Gas Combustion Products

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Energy and Power Engineering 2012年第5期4卷 353-357页

作者： Fernando Rueda Martínez miguel toledo velázquez Georgiy Polupan Juan Abugaber Francis Guillermo Jarquín López Celerino Reséndiz Rosas José ángel Ortega Herrera Researching and Graduate Section Applied Hydraulics and Thermal Engineering Laboratory ESIME - IPN Researching and Graduate Section ESIME Culhuacan - IPN México D.F Researching and Graduate Section Pachuca Technological Institute Pachuca Hidalgo México Researching and Graduate Section. ESIME - IPN

The combustion products of fuels containing the elements C, H, O, N and S are calculated. The methodology is based on the equations obtained in the stoichiometric balance of atoms. The adiabatic flame temperature is determined considering that the pressure of the boiler furnace remains constant. The scope of this work is limited to the analysis of natural gas (methane) with molecular formula CH4. The methodology can, however, be employed for the calculation of combustion products of a great variety of hydrocarbons under the established *** the development of the methodology two cases are contemplated: Φ ≤ 1 (lean and stoichiometric mixture) and Φ > 1 (rich mixture). In the first case it is considered that when the combustion is complete, the combustion products are O2, H2O, CO2, N2, SO2, and the solution follows directly. When the combustion is incomplete, however, the products H, O, N, H2, OH, CO, NO, O2, H2O, CO2, N2 and SO2 can be generated, according to Stephen R. Turns, (2000). When bal-ances of atoms are performed, four conservation equations are obtained, one for each of the C, O, H and N elements. An additional restriction requires that the sum of the molar fractions of the products equals one mol. Finally, seven equilibrium constants, corresponding to the seven chemical reactions of combustion, are introduced. All this provides a system of four nonlinear equations which is solved with the Newton-Raphson method.

关键词： Combustion Products Adiabatic Flame Stoichiometric Mixture

Refractive outcomes after V4c Toric collamer lens implantation over 1y of follow-up

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1322-1330页

作者： Humberto Carreras-Díaz Josefina Reñones de Abajo María del Rosario Carreras-Díaz Amalia Lorente-velázquez Vithas Eurocanarias Las Palmas de Gran Canaria 35004Spain University Hospital of Girona Doctor Josep Trueta Gerona 17007Spain Departament of Optometry and Vision Faculty of Optics and OptometryComplutense University of MadridMadrid 28040Spain

AIM:To evaluate refractive outcomes and corneal astigmatism changes after Toric implantable collamer lens with a central port(V4c T-ICL)implantation over 1y of ***:A retrospective study was performed including 50 eyes of 50 patients that underwent V4c T-ICL ***(UDVA)and corrected(CDVA)distance visual acuities,refraction,refractive and corneal astigmatism changes and corneal coupling correction were evaluated preoperatively,1 and 12mo *** analysis was used for astigmatism *** of adjustment(CAdj)was calculated for corneal coupling ***:The mean UDVA achieved was 0.03 logMAR at 1mo and remained unchanged throughout the whole follow-up(P=0.193).At the last visit,84%of the eyes achieved a CDVA of 0.00 logMAR or *** spherical equivalent refraction(SEQ),96%of eyes were ranges of±1.00 D and 84%of them within±0.50 ***,94%of eyes had a remaining refractive cylinder within±1.00 D and 78%of them within±0.50 ***,SEQ and refractive cylinder,remain stable over the postoperative follow-up(P=1.000 and P=0.660,respectively).In terms of surgically induced astigmatism(SIA),no statistically significant differences were found over the follow-up(P=0.102)and under correction was found with a correction index lower than the unit at each visit.A keratometric astigmatism induced of 0.59±0.53(vector mean:0.26×73º)D was reached at the last *** significant changes in terms of corneal astigmatism orientation were reported over post-surgery visits(P=0.129 and P=0.097 at 1 and 12mo respectively).No clinical significance was found for CAdj on with-the-rule *** postoperative complications resulting from the surgery were ***:Refractive outcomes suggest that the V4c T-ICL implantation for correction of myopic astigmatism was satisfactory in terms of effectiveness,safety,and stability during 1y of *** astigmatism induced by the incision around 0.5 D is achieved

关键词： V4c Toric collamer lens corneal astigmatism surgically induced astigmatism corneal coupling

Effect of the Coulomb and dielectric forces on the onset of Rayleigh-Bénard convection

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Acta Mechanica Sinica 2024年第6期40卷 64-77页

作者： Zhonglin Du Pedro A.Vázquez Jian Wu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China Heilongjiang Key Laboratory of Micro-and Nano-scale Fluid Flow and Heat Transfer Harbin150001China Departamento de Física Aplicada III ETSIIUniversidad de SevillaSevilla41092Spain

In this paper,the effect of Coulomb and dielectric forces on the onset of Rayleigh-Bénard convection(RBC)in a dielectric liquid layer contained between two parallel electrode plates has been numerically *** different operating conditions have been considered in electrohydrodynamic(EHD)conduction:ohmic and saturation,and variations in the physical properties of the dielectric fluid with *** electric equations and the state equations based on the Boussinesq approximation are integrated in the framework of OpenFOAM buoyantBoussinesqPimpleFoam *** results show that in the ohmic regime,the combined effect of Coulomb and dielectric forces promotes the onset of RBC flow,while in the saturation state,the inhibition of RBC flow by Coulomb force is more *** value of the critical Rayleigh number Ra decreases with increasing electric Reynolds number ReE in the ohmic regime,whereas in the saturation state,the critical Ra increases with increasing *** the saturation regime,the flow field always has a steady flow in the range of parameters ***,the onset of the RBC flow promoted by the dielectric force is more pronounced in the ohmic *** to the presence of the dielectric force,the flow field exhibits periodic oscillatory flow at low electric Reynolds numbers for the range of parameters considered.

关键词： EHD conduction Dielectric force Rayleigh-Bénard convection OpenFOAM