Simulación del desempeño de tres perfiles aerodinámicos en flujo turbulento

This work presents the lift and drag coefficient curves, as functions of the angle of attack, for the NACA0012, S809 and SG6043 airfoils in turbulent flow conditions. The objective is to identify the airfoil with the best aerodynamic performance under conditions that are descriptive of small scale wind turbine. With the use of OpenFOAM, an analysis was done by numerical simulation. In the case of the NACA0012 airfoil, it was found that the performance is insensitive to the changes in turbulence and the Reynold number. The aerodynamic response of the S809 airfoil is to increase both the drag and lift as the turbulence increases. The SG6043 airfoil responds the best out of the three in turbulent flow, given that the lift curves mostly increase with the turbulence. The curves reported in this work are new and not found in previous literature. Keywords: aerodynamics, lift, drag, turbulence References [1]R. Madriz-Vargas, A. Bruce, M. Watt, L. G. Mogollón and H. R. Álvarez, «Community renewable energy in Panama: a sustainability assessment of the “Bocade Lura” PV-Wind-Battery hybrid power system,» Renewable Energy and Environmental Sustainability, vol. 2, nº 18, pp. 1-7, 2017. https://doi.org/10.1051/rees/2017040. [2]S. Mertenes, «Wind Energy in the Built Environment, » Ph.D. dissertation. Multi-Science, Brentwood, 2006. [3]P. Giguere and M. S. Selig, «New airfoils for small horizontal axis wind turbines,» Journal of Solar Energy Engineering-transactions, vol. 120, pp. 108-114, 1988. https://doi.org/10.1115/1.2888052. [4]A. K. Wright and D. H. Wood, «The starting and low wind speed behaviour of a small horizontal axis wind turbine,» Journal of wind engineering and industrial aerodynamics, vol. 92, nº 14-15, pp. 1265-1279, 2004. https://doi.org/10.1016/j.jweia.2004.08.003. [5]G. Richmond-Navarro, M. Montenegro-Montero and C. Otárola, «Revisión de los perfiles aerodinámicos apropiados para turbinas eólicas de eje horizontal y de pequeña escala en zonas boscosas,» Revista Lasallista de Investigación, vol. 17, nº 1, pp. 233-251, 2020. https://doi.org/10.22507/rli.v17n1a22. [6]A. Tummala, R. K. Velamati, D. K. Sinha, V. Indraja and V. H. Krishna, «A review on small scale wind turbines, » Renewable and Sustainable Energy Reviews,vol. 56, pp. 1351-1371, 2016. https://doi.org/10.1016/j.rser.2015.12.027. [7]L. Pagnini, M. Burlando and M. Repetto, «Experimental power curve of small-size wind turbines in turbulent urban environment,» Applied Energy, vol. 154,pp. 112-121, 2015. https://doi.org/10.1016/j.apenergy. 2015.04.117. [8]W. D. Lubitz, «Impact of ambient turbulence on performance of a small wind turbine,» Renewable Energy, vol. 61, pp. 69-73, 2014. https://doi.org/10.1016/j.renene.2012.08.015. [9]P. Devinant, T. Laverne and J. Hureau, «Experimental study of wind-turbine airfoil aerodynamics in high turbulence, » Journal of Wind Engineering and Industrial Aerodynamics, vol. 90, nº 6, pp. 689-707, 2002. https://doi.org/10.1016/S0167-6105(02)00162-9. [10]C. Sicot, P. Devinant, S. Loyer and J. Hureau, «Rotational and turbulence effects on a wind turbine blade. Investigation of the stall mechanisms,» Journal ofwind engineering and industrial aerodynamics, vol. 96, nº 8-9, pp. 1320-1331, 2008. https://doi.org/10.1016/j.jweia.2008.01.013. [11]C. R. Chu and P. H. Chiang, «Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine,» Journal of Wind Engineering and Industrial Aerodynamics, vol. 124, pp. 82-89, 2014. https://doi.org/10.1016/j.jweia.2013.11.001. [12]Y. Kamada, T. Maeda, J. Murata and Y. Nishida, «Visualization of the flow field and aerodynamic force on a Horizontal Axis Wind Turbine in turbulent inflows,» Energy, vol. 111, pp. 57-67, 2016. https://doi.org/10.1016/j.energy.2016.05.098. [13]Q. A. Li, J. Murata, M. Endo, T. Maeda and Y. Kamada, «Experimental and numerical investigation of the effect of turbulent inflow on a Horizontal Axis WindTurbine (Part I: Power performance),» Energy, vol.113, pp. 713-722, 2016. https://doi.org/10.1016/j.energy.2016.06.138. [14]S. W. Li, S. Wang, J. P. Wang and J. Mi, «Effect of turbulence intensity on airfoil flow: Numerical simulations and experimental measurements,» Applied Mathematics and Mechanics, vol. 32, nº 8, pp. 1029-1038, 2011. https://doi.org/10.1007/s10483-011-1478-8. [15]S. Wang, Y. Zhou, M. M. Alam and H. Yang, «Turbulent intensity and Reynolds number effects on an airfoil at low Reynolds numbers,» Physics of Fluids, vol. 26, nº11, p. 115107, 2014. https://doi.org/10.1063/1.4901969. [16]M. Lin and H. Sarlak, «A comparative study on the flow over an airfoil using transitional turbulence models, » AIP Conference Proceedings, vol. 1738, p.030050, 2016. https://doi.org/10.1063/1.4951806. [17]Langley Research Center, «Turbulence Modelling Resource,» NASA, [Online]. Available: https://turbmodels.larc.nasa.gov/langtrymenter_4eqn.html. [Last access: 08 03 2021].En este trabajo se presentan las curvas de coeficientes de sustentación y arrastre en función del ángulo de ataque, para los perfiles NACA0012, S809 y SG6043 en condiciones de flujo turbulento. El objetivo es identificar el perfil aerodinámico que tiene mejor rendimiento en condiciones de relevancia para las turbinas eólicas de pequeña escala. El análisis se realizó mediante simulación utilizando OpenFOAM. En el caso del perfil NACA0012 se encuentra que su desempeño es poco sensible a cambios en la turbulencia y en el número de Reynolds. La respuesta del perfil S809 es de aumentar tanto el arrastre como la sustentación al aumentar la turbulencia. El desempeño del perfil SG6043 resulta ser el más conveniente en flujo turbulento pues las curvas de sustentación en su mayoría aumentan al aumentar la turbulencia. Las curvas que se reportan aquí son inéditas y no se encuentra en la literatura. Palabras clave: aerodinámica, sustentación, arrastre, turbulencia. Referencias [1]R. Madriz-Vargas, A. Bruce, M. Watt, L. G. Mogollón y H. R. Álvarez, «Community renewable energy in Panama: a sustainability assessment of the “Bocade Lura” PV-Wind-Battery hybrid power system,» Renewable Energy and Environmental Sustainability, vol. 2, nº 18, pp. 1-7, 2017. https://doi.org/10.1051/rees/2017040. [2]S. Mertenes, «Wind Energy in the Built Environment, » Ph.D. dissertation. Multi-Science, Brentwood, 2006. [3]P. Giguere y M. S. Selig, «New airfoils for small horizontal axis wind turbines,» Journal of Solar Energy Engineering-transactions, vol. 120, pp. 108-114, 1988.https://doi.org/10.1115/1.2888052 [4]A. K. Wright y D. H. Wood, «The starting and low wind speed behaviour of a small horizontal axis wind turbine,» Journal of wind engineering and industrial aerodynamics, vol. 92, nº 14-15, pp. 1265-1279, 2004. https://doi.org/10.1016/j.jweia.2004.08.003. [5]G. Richmond-Navarro, M. Montenegro-Montero y C. Otárola, «Revisión de los perfiles aerodinámicos apropiados para turbinas eólicas de eje horizontal y depequeña escala en zonas boscosas,» Revista Lasallista de Investigación, vol. 17, nº 1, pp. 233-251, 2020. https://doi.org/10.22507/rli.v17n1a22. [6]A. Tummala, R. K. Velamati, D. K. Sinha, V. Indraja y V. H. Krishna, «A review on small scale wind turbines, » Renewable and Sustainable Energy Reviews,vol. 56, pp. 1351-1371, 2016. https://doi.org/10.1016/j.rser.2015.12.027. [7]L. Pagnini, M. Burlando y M. Repetto, «Experimental power curve of small-size wind turbines in turbulent urban environment,» Applied Energy, vol. 154,pp. 112-121, 2015. https://doi.org/10.1016/j.apenergy. 2015.04.117. [8]W. D. Lubitz, «Impact of ambient turbulence on performance of a small wind turbine,» Renewable Energy, vol. 61, pp. 69-73, 2014. https://doi.org/10.1016/j.renene.2012.08.015. [9]P. Devinant, T. Laverne y J. Hureau, «Experimental study of wind-turbine airfoil aerodynamics in high turbulence, » Journal of Wind Engineering and Industrial Aerodynamics, vol. 90, nº 6, pp. 689-707, 2002. https://doi.org/10.1016/S0167-6105(02)00162-9. [10]C. Sicot, P. Devinant, S. Loyer y J. Hureau, «Rotational and turbulence effects on a wind turbine blade. Investigation of the stall mechanisms,» Journal ofwind engineering and industrial aerodynamics, vol. 96, nº 8-9, pp. 1320-1331, 2008. https://doi.org/10.1016/j.jweia.2008.01.013. [11]C. R. Chu y P. H. Chiang, «Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine,» Journal of Wind Engineering and Industrial Aerodynamics, vol. 124, pp. 82-89, 2014. https://doi.org/10.1016/j.jweia.2013.11.001. [12]Y. Kamada, T. Maeda, J. Murata y Y. Nishida, «Visualization of the flow field and aerodynamic force on a Horizontal Axis Wind Turbine in turbulent inflows,» Energy, vol. 111, pp. 57-67, 2016. https://doi.org/10.1016/j.energy.2016.05.098. [13]Q. A. Li, J. Murata, M. Endo, T. Maeda y Y. Kamada, «Experimental and numerical investigation of the effect of turbulent inflow on a Horizontal Axis WindTurbine (Part I: Power performance),» Energy, vol.113, pp. 713-722, 2016. https://doi.org/10.1016/j.energy.2016.06.138. [14]S. W. Li, S. Wang, J. P. Wang y J. Mi, «Effect of turbulence intensity on airfoil flow: Numerical simulations and experimental measurements,» Applied Mathematics and Mechanics, vol. 32, nº 8, pp. 1029-1038, 2011. https://doi.org/10.1007/s10483-011-1478-8. [15]S. Wang, Y. Zhou, M. M. Alam y H. Yang, «Turbulent intensity and Reynolds number effects on an airfoil at low Reynolds numbers,» Physics of Fluids, vol. 26, nº11, p. 115107, 2014. https://doi.org/10.1063/1.4901969. [16]M. Lin y H. Sarlak, «A comparative study on the flow over an airfoil using transitional turbulence models, » AIP Conference Proceedings, vol. 1738, p.030050, 2016. https://doi.org/10.1063/1.4951806. [17]Langley Research Center, «Turbulence Modelling Resource,» NASA, [En línea]. Disponible: https://turbmodels.larc.nasa.gov/langtrymenter_4eqn.html. [Último acceso: 08 03 2021]

Shrouded wind turbine performance in yawed turbulent flow conditions

Artículo científico. Wind Engineering XX(X):1–7 ©The Author(s) 2021 Reprints and permission: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/ToBeAssigned www.sagepub.com/Wind turbines represent a growing energy source worldwide. In many cases, operating in turbulent and changing wind direction spots. In this work, we use a wind tunnel to analyse the effect of the turbulence in a wind turbine provided with a Wind Lens flow concentrator, under yaw conditions, for turbulence intensity values of 10% and 15%. Measurements are made of the power coefficient as a function of the Tip Speed Ratio using two types of Wind Lens, CiiB5 and CiiB10, at yaw angles from 0 to 30 . In general, for the turbine with Wind Lens, an increase of the yaw angle causes a reduction of the power coefficient. If the turbine operates with the CiiB10, the stronger the turbulence, the greater performance is obtained. In conclusion, for the case of turbulent flow and yaw = 20 or less, the Wind Lens turbine offers better performance than without the flow concentrator

A Magnus Wind Turbine Power Model Based on Direct Solutions Using the Blade Element Momentum Theory and Symbolic Regression

A model of the power coefficient of a mid-scale Magnus wind turbine using numerical solutions of the Blade Element Momentum Theory and symbolic regression is presented. A direct method is proposed for solving the nonlinear system of equations which govern the phenomena under study.The influence of the tip speed ratio and the number, aspect ratio, and the angular speed of the cylinder son the turbine performanceisobtained. Results show that the máximum power coefficientisontheorderof 0.2, whichis obtained witht wolowa spectratio cylinders, adimension lesscy linder speed ratio of 2, and a turbine tip-speed ratio between 2 and 3. The predicted power coefficient at low tip-speed ratio suggests that a Magnus turbine may be adequate in the urban environment

Opportunities for renewable energy electrification in remote areas of Costa Rica

Perspectives on Global Development and Technology. Online Publication Date: 10 Dec 2019Countries around the world are politically driven to move toward a low-carbon future by embracing renewable energies technologies for electricity generation. With abundance of renewable energy resources, Costa Rica has produced over 95% of its electricity from hydro, geothermal and wind power plants. Only 1% of its population live without electricity, mainly in remote territories where rural off-grid electrification is very challenging. The purpose of this research is to understand the opportunities to reach universal electricity access in Costa Rica by using renewables. This paper highlights that a greater level of engagement is needed from local leaders develop efficient solutions. There are more opportunities to access funding schemes if projects are linked with the education sector. Hence, financial and technical support from external entities can be granted supporting the sustainability of the power systems and its expected socio-economic outcomes. This funding scheme can be replicated in other developing countries

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Desempeño de turbinas eólicas Magnus de eje horizontal en función de sus variables geométricas y cinemáticas

This study covers the analysis of a horizontal axis wind turbine that uses rotating cylinders instead of blades. The working principle of this wind generator is the Magnus effect, which happens when the cylinders start rotating, giving rise to an interaction between the incident wind and the air dragged by the walls of the moving cylinders. This generates lift which puts the turbine in motion. The goal of this investigation was to characterize this type of turbine by means of numerical and mathematics methods that permit determination of the power vs wind speed curve’s behaviour as a function of working parameters of Magnus horizontal axis wind turbines. In order to study turbines performance, a non-iterative method is proposed and implemented in code. This approach allows the prediction of the output power, which is validated by experimental measurements of conventional turbines. The method was adapted to Magnus turbines. It was used to obtain the power curve behavior given geometry variations including changes in the number of rods, as well as turbine and cylindrical blade’s angular velocities.Este estudio presenta el análisis de una turbina eólica de eje horizontal que utiliza cilindros en rotación, en lugar de aspas con perfiles alares. El principio de funcionamiento de este generador eólico es el efecto Magnus, que sucede cuando las aspas cilíndricas empiezan a rotar y se da una interacción entre la corriente de viento incidente y el aire que es arrastrado por las paredes de los cilindros en movimiento. De esta forma, se obtiene la sustentación que pone en movimiento la turbina. El objetivo de la investigación es caracterizar este tipo de turbina mediante modelos numéricos y matemáticos, que permitan determinar el comportamiento de la curva de potencia en función del viento ante variaciones de los parámetros de funcionamiento de la turbina tipo Magnus de eje horizontal, a saber, la geometría del cilindro y las velocidades de rotación tanto de la turbina como del cilindro. Para estudiar el desempeño de la turbina, se propone un método numérico no iterativo, que es implementado en un código que permite predecir el rendimiento de turbinas de eje horizontal, el cual es validado con mediciones experimentales de turbinas convencionales. Posteriormente, se adecúa el código para aplicarlo a turbinas Magnus y con ello se obtiene el comportamiento de la curva de potencia ante variaciones en la geometría y cantidad de cilindros, así como las velocidades angulares de la turbina y del aspa cilíndrica.

Optimización aerodinámica de una turbina eólica de eje horizontal para aplicaciones de pequeña escala en zonas boscosas

El viento es una fuente de energía renovable que ha tomado mucho auge en las últimas décadas. En particular en Costa Rica, alrededor del 10 % de la matriz eléctrica es energía eólica. Tomando en cuenta que este país posee una abundante vegetación, este trabajo se enfoca en determinar las características aerodinámicas óptimas de un rotor de turbina eólica de eje horizontal, de menos de 3 metros de diámetro, mediante simulación numérica, para aplicaciones en zonas boscosas de bajo potencial eólico. En particular, orientando los esfuerzos a brindar una fuente de energía a viviendas ubicadas en zonas indígenas, que están lejos de las redes de distribución eléctrica. En la primera parte de esta investigación se describe el recurso eólico en Costa Rica, aprovechando los datos de 37 estaciones meteorológicas distribuidas a lo largo y ancho del territorio; las cuales ofrecen registros entre 2007 y 2017. Se encuentra que, a 10 metros sobre el suelo, el viento sopla principalmente entre 3 y 5 m/s con una intensidad de turbulencia de hasta 30 %, estos resultados validan el foco de esta investigación, al demostrarse que el potencial eólico es bajo debido a las bajas velocidades y a la elevada intensidad de turbulencia. La segunda parte del documento contiene un modelado del viento en las zonas de interés, con la finalidad de conocer de forma detalla las condiciones en las cuales operará el rotor que se pretende diseñar. Para estos efectos se instrumentan varias torres meteorológicas con anemómetros a diferentes alturas y se determina que la temperatura, junto con la altura, son factores relevantes para describir la velocidad del viento en zonas boscosas. Se encuentra un valor de intensidad de turbulencia de alrededor del 30 % como el más frecuente entre los datos tomados. También se determina que una zona localmente sin obstáculo se asocia a una menor intensidad de turbulencia, lo que deberá ser tomado en cuenta para una eventual instalación del rotor que se diseña en esta tesis doctoral. El capítulo 3 contiene el diseño propiamente del rotor, una vez conocido el recurso eólico de manera general en el país, y de forma específica en zonas boscosas. Se emplea simulación numérica para conocer el desempeño del perfil SG6043 en condiciones de alta turbulencia y posteriormente con los resultados se diseña el rotor mediante el programa SWRDC, siglas de Small Wind turbine Rotor Design Code. El cual fue diseñado en Matlab por terceros y en este caso implementado con los datos de viento propios de la zona de interés. Se obtiene un rotor que puede generar hasta 1070 kWh de energía anual, frente a los 114 kWh que generaría un rotor de turbina comercial en las mismas condiciones. Finalmente en la cuarta parte de esta investigación se presentan los resultados de la pasantía realizada en la Universidad de Kyushu en Japón, donde se investiga el efecto un difusor en flujo turbulento. Para ello se emplea un túnel de viento con una sección de pruebas de 2 metros de alto por 3.6 metros de ancho. En dicho túnel se coloca una rejilla generadora de turbulencia y el difusor. Se encuentra que el efecto positivo del difusor en el flujo se ve potenciado por la turbulencia. Por lo que se concluye que este tipo de dispositivos son adecuados para turbinas que operan en condiciones de flujo turbulento.Instituto Tecnológico de Costa Rica///Costa RicaUCR::Vicerrectoría de Investigación::Sistema de Estudios de Posgrado::Ingeniería::Doctorado en Ingenierí

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