Vertical Axis Wind Turbine Design Load Cases Investigation and Comparison with Horizontal Axis Wind Turbine

AbstractThe paper studies the applicability of the IEC 61400-1 ed.3, 2005 International Standard of wind turbine minimum design requirements in the case of an onshore Darrieus VAWT and compares the results of basic Design Load Cases (DLCs) with those of a 3-bladed HAWT. The study is based on aeroelastic computations using the HAWC2 aero-servo-elastic code A 2-bladed 5 MW VAWT rotor is used based on a modified version of the DeepWind rotor For the HAWT simulations the NREL 3-bladed 5 MW reference wind turbine model is utilized Various DLCs are examined including normal power production, emergency shut down and parked situations, from cut-in to cut-out and extreme wind conditions. The ultimate and 1 Hz equivalent fatigue loads of the blade root and turbine base bottom are extracted and compared in order to give an insight of the load levels between the two concepts. According to the analysis the IEC 61400-1 ed.3 can be used to a large extent with proper interpretation of the DLCs and choice of parameters such as the hub-height. In addition, the design drivers for the VAWT appear to differ from the ones of the HAWT. Normal operation results in the highest tower bottom and blade root loads for the VAWT, where parked under storm situation (DLC 6.2) and extreme operating gust (DLC 2.3) are more severe for the HAWT. Turbine base bottom and blade root edgewise fatigue loads are much higher for the VAWT compared to the HAWT. The interpretation and simulation of DLC 6.2 for the VAWT lead to blade instabilities, while extreme wind shear and extreme wind direction change are not critical in terms of loading of the VAWT structure. Finally, the extreme operating gust wind condition simulations revealed that the emerging loads depend on the combination of the rotor orientation and the time stamp that the frontal passage of gust goes through the rotor plane

Aeroelastic Analysis of B49 blade-Blatigue Project

This report is part of the EUDP Blatigue project, Fast and efficient fatigue test of large wind turbine blades. In the study the Siemens B49 blade loads are computed using HAWC2 aeroelastic code. The blade is coupled in a generic wind turbine tower and nacelle structure within HAWC2. Furthermore the basic DTU WE controller is used. The aim is to evaluate the blade fatigue and ultimate loads based on the IEC 61400-1 ed.3 standard. The results are further used in the project for the set-up and testing of the real blade at the DTU Risø Large Scale Facility. In the first part the model properties are summarized. Then the IEC load cases are simulated using the HAWC2 code and the analysis is focused on the blade performance. A blade load comparison between HAWC2 and the Siemens results is presented together with a summary of the uncertainties related with the present analysis. Finally, an analysis is performed on a potential way to compute the blade lifetime fatigue damage based on few time series instead of running the full design load basis. The work is funded by the EUDP project BLATIGUE: Fast and efficient fatigue test of large wind turbine blades under project number 64016- 0023 which is gratefully acknowledged. Several contributions have been made in the model set-up as well as in the interpretation of the results from Torben J. Larsen, Anders M. Hansen, Kim Branner, Perer Berring and Federico Belloni who are gratefully acknowledged

Buenas prácticas para la gestión de calidad en el control de la construcción de presas de relaves en una empresa supervisora de Lima – 2021

El trabajo de investigación que se presenta tiene como objetivo general, comprobar la correlación entre dos variables; gestión de calidad y control de la construcción de presas de relaves en una empresa supervisora, Lima 2021. La muestra estuvo conformada por 17 supervisores con experiencia en monitoreo y control en construcción de presas de relaves. La metodología empleada en el desarrollo del trabajo se justifica en la aplicación del enfoque cuantitativo, con el estudio de variables correlacionales donde se muestra el seguimiento del proceso de la investigación, usando técnicas, tales como encuesta, diseño de un instrumento y cuestionario con escala de Likert. Los resultados de las encuestas han demostrado como la gestión de calidad impacta sobre el control de la construcción de presas de relaves, el cual representa una dependencia positiva fuerte. Se determina que el uso de las buenas prácticas en gestión de calidad para el control de la construcción de presas de relaves tiene una influencia positiva en el nivel de satisfacción de los supervisores.Escuela de Postgrad

Hepatic abscess in a pre-existed simple hepatic cyst as a late complication of sigmoid colon ruptured diverticula: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hepatic abscesses have been reported as a rare complication of diverticulitis of the bowel. This complication is recognized more commonly at the time of the diagnosis of diverticulitis, or ruptured diverticula, but also can be diagnosed prior to surgery, or postoperatively.</p> <p>Case presentation</p> <p>This report describes a man who developed an hepatic abscess within a simple hepatic cyst, two months after operation for ruptured diverticula of the sigmoid colon. The abscess was drained surgically and the patient made a complete recovery.</p> <p>Conclusion</p> <p>The development of an hepatic abscess in a pre-existing hepatic cyst, secondary to diverticulitis, is a rare complication. A high degree of clinical suspicion is required for immediate diagnosis and treatment.</p