Examinando por Autor "Guerrero-Villar, Francisca"
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Ítem A comparative study of performance and regulated emissions in a medium-duty diesel engine fueled with sugarcane diesel-farnesane and sugarcane biodiesel-LS9(ELSEVIER, 2019-06-01) Soto, Felipe; Marques, Gian; Torres-Jiménez, Eloísa; Vieira, Bráulio; Lacerda, André; Armas, Octavio; Guerrero-Villar, FranciscaTwo sugarcane biofuels and mineral diesel fuel are tested under full load conditions, under the same values of performance and under the European Transient Cycle on an engine test bench, without any modifications to the ECU. The target is to compare engine performance and emissions. At full load, engine performance varies due to the variation in LHV. Under the same values of performance, the sugarcane biodiesel-LS9 provides the lowest THC emissions. The higher CN and exhaust gas recirculation of the sugarcane biodiesel-LS9 and the higher H/C ratio of the sugarcane diesel-farnesane compared to the diesel S50 provide a NOx reduction. Neither the increment in bsfc nor the increment of %EGR for the sugarcane biodiesel-LS9 deteriorate the combustion, so its CO emissions are lower. The sugarcane biodiesel-LS9 leads to the lowest NOx and PM specific emissions under transient operation, followed by the sugarcane diesel-farnesane. The THC and CO specific emissions are higher for the biofuels in comparison to the diesel S50. The main reason for these results is the impact of the properties of the biofuels on the ECU response However, both biofuels produce less harmful emissions at idle conditions, which supports their usage to reduce exhaust emissions in urban areas.Ítem A numerical and experimental study of a new Savonius wind rotor adaptation based on product design requirements(Elsevier, 2018-01-09) Mercado-Colmenero, Jorge Manuel; Rubio-Paramio, Miguel Ángel; Guerrero-Villar, Francisca; Martín-Doñate, CristinaThis paper presents the numerical-experimental study carried out on a new rotor adapted from a Savonius rotor. Aesthetic, ergonomic and functional requirements have been incorporated into it in order to be part of sustainable consumer products. The new rotor consists of a parametric model adaptable to the dimensions and geometry of the products which it will be part of. A set of translation, symmetry, rotation and scaling operations have been applied to the bucket sections of the Savonius rotor by means of transforming the initial cylindrical buckets into topological surfaces with an organic shape. The new modified Savonius rotor and the conventional Savonius with the same Aspect Ratio have been tested in an open jet wind tunnel in order to verify the influence level of product design parameters on rotor performance, in terms of power coefficient, torque coefficient and mechanical power generated. Experimental tests have been carried out for Reynolds values in the range of [3,430·104 and 1,419·105]. A numerical analysis using an incompressible unsteady Reynolds average Navier Stockes model has been validated by means of the experimental results. Experimental and numerical results coincide with a 3.5% error. The behavior of the turbine has been analyzed by varying the angle of rotation for the sections of its buckets. Using a rotation angle of 45 ° the power coefficient values improve by 32% compared to the values obtained using an angle of 0 °. The rotor has been dimensioned for its application in a patented consumer product of small dimensions and requirements of lateral accessibility to its interior. Under these limited conditions the rotor meets the small-scale energy requirements of the product. The new rotor is designed as an aid to the energy consumption of the product in which it is incorporated, maintaining the advantages of a conventional Savonius rotor as self-starting, easy manufacture and maintenance, obtaining at the same time a product that sells better, is more able to integrate into its environment and is customizable for the consumer.Ítem Alternative Calibration of Cup Anemometers: A Way to Reduce the Uncertainty of Wind Power Density Estimation(MDPI, 2019-04-30) Guerrero-Villar, Francisca; Dorado-Vicente, Rubén; Medina-Sánchez, Gustavo; Torres-Jiménez, EloísaThis study presents a procedure to reduce the uncertainty of wind power density estimations, which is useful to improve the energy production predictions of wind farms. Power density is usually determined from the wind speed measured by a cup anemometer and the air density value (conventional procedure). An alternative procedure based on wind speed and dynamic pressure estimations provided by a cup anemometer is proposed. The dynamic pressure is obtained by means of a calibration curve that relates the anemometer rotation frequency and the dynamic pressure measured by a Pitot tube. The quadratic regression, used to define the calibration curve, and its uncertainty are both detailed. A comparison between the alternative procedure and the conventional one points out the advantage of the proposed alternative since results show a high reduction of the indirect measurement uncertainty of wind power density.Ítem Development of Vertical Wind Turbines via FDM Prototypes(ELSEVIER, 2015-12-25) Guerrero-Villar, Francisca; Torres-Jiménez, Eloísa; Dorado-Vicente, Rubén; Jiménez-González, Jose IgnacioIn the present work, we propose to design and manufacture a specific Vertical Axis Wind Turbine (VAWT) prototype in order to evaluate its performance when some geometrical parameters are modified. The key idea is to take advantage of additive manufacturing flexibility to print the main components in an easy way and at low cost. Prototype size (scale 1:250, with respect to a 2 MW wind turbine) is small enough to be tested in a 40 cm x 40 cm wind tunnel. We use a Fused Deposition Modeling (FDM) machine to print the prototype, which is previously designed via CAD software. Different tests have been performed to determine an adequate printing configuration, mainly regarding how layer height influences roughness and printing time. Main dimensions, roughness and weight of the printed pieces were measured and finally, parts of highest quality were used to assemble a working prototype. The methodology presented in this paper shows it is possible to manufacture a wind turbine prototype with the following characteristics: flexibility to modify the design throughout the course of the investigation, low cost and low time needed to obtain the components with enough quality.Ítem Influence of ambient conditions on wind speed measurement: Impact on the annual energy production assessment(ELSEVIER, 2019-09-01) Guerrero-Villar, Francisca; Dorado-Vicente, Rubén; Fike, Matej; Torres-Jiménez, EloísaThe Annual Energy Production (AEP) estimations are crucial to analyze the potential of wind energy projects. To calculate the AEP of a wind farm, it is necessary to accurately measure the wind speed, because small errors in these measures lead to significant deviations in the wind turbine power curve. In-field wind speed is usually measured by means of cup anemometers, which are calibrated within wind tunnels. In-field ambient conditions differ from those at the laboratory, which increases the uncertainty of the wind speed measures performed at the location of the turbine. The present work is focused on analyzing the effect of the following ambient parameters on the cup anemometer behavior: temperature, humidity and atmospheric pressure. In order to reach this target, experimental tests in a wind tunnel were performed, which allows minimizing the effect of the rest of influence parameters: turbulence, average flow inclination angle and flow direction. With this work it is determined how flow air viscous forces affect the cup anemometers, changing its rotation frequency. This explanation concludes that a variation on air temperature, humidity and/or pressure modifies moist air kinematic viscosity, which leads to change the friction between air and cups and, consequently, the cup anemometers rotational frequency. In most cases, the kinematic viscosity is inversely proportional to the air density and therefore, higher in-field densities, compared to those at the laboratory where the anemometer was calibrated, lead to underestimate the wind speed, and vice versa. The fact that this effect has been quantified during the calibration process is quite important, since it allows removing the influence of the environmental parameters studied; so that by modifying the calibration methodology, the accuracy of cup anemometers would be optimized. In order to clarify how the moist air kinematic viscosity influences the calibration curve, the calibration measurements of a real cup anemometer are mapped into a new dimensionless abacus, with the Tip Speed Ratio (TSR) and the Reynold’s number as coordinates. The key idea is that the rotation frequency of the cup anemometer is related to both wind speed and moist air kinematic viscosity. This relation is mathematically described by the equation of a hyperbolic paraboloid surface up to a value of wind speed of 15.3 m/s.Ítem Performance and regulated emissions of a medium-duty diesel engine fueled with biofuels from sugarcane over the European steady cycle (ESC)(ELSEVIER, 2021-02-15) Soto, Felipe; Marques, Gian; Soto Izquierdo, Lian; Torres-Jiménez, Eloísa; Quaglia, Saulo; Guerrero-Villar, Francisca; Dorado-Vicente, Rubén; Abdalla, JordanaThe use of diesel-farnesane and sugarcane biodiesel is showing significant potential for reducing harmful emissions from Brazilian road transport. Both biofuels are obtained from sugarcane through synthetic biology that requires fermentation. The present work studies the effect of the sugarcane biofuels, compared to regular diesel fuel, on the performance and emissions of a modern medium-duty diesel engine following the European Steady Cycle (ESC) test procedure. Diesel-farnesane showed the lowest particulate matter (PM) specific emissions. Specific nitrogen oxides (NOx) emissions from diesel fuel were above the standard limit, while sugarcane biodiesel produced the lowest emissions. All tested fuels produced specific carbon monoxide (CO) emissions below the standard limit, but the biofuels showed higher values than the reference fuel. Sugarcane biodiesel showed an inhibition effect on the oxidation process at the Diesel Oxidation Catalyst (DOC), leading to the highest specific CO emissions after the DOC. Specific total hydrocarbons (THC) emissions were well below the standard limits for all tested fuels. Concerning the regulated emissions for diesel engines (g/h), the use of sugarcane biodiesel led to PM and NOx reductions of 32.4% and 37.3%, while diesel-farnesane led to 41.7% and 6.08% reductions, respectively. These notable reductions in harmful emissions support the application of sugarcane biofuels to road transport.