Numerical analysis for detecting head losses in trifurcations of high head in hydropower plants

Aguirre, Carlos Andrés; Camacho, Ramiro Gustavo Ramírez; Oliveira, Waldir de; Avellan, François

doi:10.1016/j.renene.2018.07.021

Cited by 8 publications

(7 citation statements)

References 7 publications

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“…For this, the number of elements is increased and its impact on results is measured. Similar approaches to mesh independence for turbomachinery, are presented in Aguirre et al (2019), Sarmiento et al (2020 and Sarmiento et al (2021).…”

Section: Definition Of Computational Domains and Mesh Generationmentioning

confidence: 87%

Free and Non-Free Vortex Design for Axial Fans with Circumferential Sweep through CFD Techniques

2022

JAFM

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The sound generated by axial flow fans has become increasingly important in several industrial areas. These devices represent considerable noise sources that must be considered from the design stage. The scope of this research work is to present an axial fan design methodology based on the theory of the wing lift and to compare the aerodynamic and aeroacoustics behavior with the free vortex and the non-free vortex conditions. The effect of forward circumferential sweep on the rotor blades is analyzed in both conditions, which consists of a displacement in the tangential direction in the direction of rotor rotation. A cubic polynomial function is proposed for the construction of the blade geometry with circumferential sweep. It defines the center line of the blade and it is taken at 50% of the leading edge of each blade profile. The methodology for analyzing aeroacoustics behavior in fans is based on the integration of Computational Aeroacoustics and Computational Fluid Dynamics in order to analyze aerodynamic behavior, sound power level and sound pressure level at the preliminary design stage. It was verified that although both rotors present a similar aerodynamic behavior (the NFV rotor has a slightly lower performance), according to the analysis of local sound sources, the NFV rotor presents a slight decrease in the sound sources. It was also verified that the NFV rotor presents 2.2 dB less in sound pressure level than the FV rotor.

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Section: Definition Of Computational Domains and Mesh Generationmentioning

confidence: 87%

Free and Non-Free Vortex Design for Axial Fans with Circumferential Sweep through CFD Techniques

2022

JAFM

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“…The turbulence model was the k-ε (approved by Wei et al, 2006) and simulations were performed in permanent regime, since any condition of flow at the dripper output was introduced aiming to compare the result with manufacturer's model, which provided a nominal flow of 4 l/h. The residue was used to ensure that the convergence that could be reached was 10-4 (as Aguirre et al, 2019) and the number of iterations required for convergence of dripper piping system was equal to 100.…”

Section: Methodsmentioning

confidence: 99%

Modeling and hydraulic performance evaluation of a dripper device coupled to a branched water distribution network

et al. 2019

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Irrigation is responsible for approximately 70% of the world’s freshwater consumption and is one of the key factors behind the growing global water scarcity. Irrigation systems and techniques are extremely differentiated and complex. In this context, tools of computational fluid dynamics (CFD) earn relevance, allowing a detailed analysis and forecast of hydraulic behavior in different situations. In order to evaluate flow details in a dripper, this study applies CFD tools to study a drip irrigation system from three different perspectives: (i) analysis of the complete system of piping and dripper; (ii) analysis of only the isolated dripper expanded and biphasic model; and (iii) analysis of the isolated dripper operating in transient regime. Modeling results allowed a full understanding about speed fields, pressure and friction loss along the geometry. The drop formation process in the dripper output could be displayed in detail, and the obtained dripper flow output was close to the nominal value of manufacturer, in the case of the isolated dripper analysis. Although a comparison with results from experiments was not possible at the time, based on manufacturers’ catalogs, results proved satisfactory, leading to successful simulations.

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“…For the hydraulic machinery, assuming that the water is an ideal fluid with incompressibility and negligible viscosity, it can be known from the Bernoulli equation that the mechanical energy of water body at any time consists of unit pressure potential energy, unit kinetic energy, and unit gravity potential energy, the sum of which is constant, then the mechanical energy of water can be calculated by(in meters) [3]:…”

Section: Head Loss Between Two Sectionsmentioning

confidence: 99%

Study on Measurement of Penstock Head Loss for Hydropower Station with Multiple Units Per Penstock

Zhou

Tuo²,

Cao

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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For a hydropower station with multiple units per penstock, how to get the head loss of penstock has usually been a difficult problem, which the core issue is that it is hard to obtain the flow of each branch pipe. For power stations that have installed flow measurement devices for all units, or have undergone absolute turbine efficiency tests, the head measurement is relatively simple, but if the flow measuring device is not installed for each unit in advance, the head loss measurement will be difficult. This paper proposes an optimized measurement method performed in a hydropower station in Pakistan, which is to arrange an ultrasonic flowmeter on the main penstock, and then use the Winter-Kennedy method and flow rate measured by Ultrasonic flow meter to calibrate the Winter-Kennedy coefficients of unit one by one. Finally, by running three units at the same time and adjusting them with the same flow rate, the total loss of the penstock is calculated. At the same time, the flow rate measured by the Winter-Kennedy coefficient and that measured by the ultrasonic method has been checked and compared. The result proves that the accuracy of the result is high, and the result has a good consistency, which can fully meet the requirements of penstock head loss calculation and evaluation. The method has a certain practical value and can be referred to by other power station which has similar measurement.

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Numerical analysis for detecting head losses in trifurcations of high head in hydropower plants

Cited by 8 publications

References 7 publications

Free and Non-Free Vortex Design for Axial Fans with Circumferential Sweep through CFD Techniques

Free and Non-Free Vortex Design for Axial Fans with Circumferential Sweep through CFD Techniques

Modeling and hydraulic performance evaluation of a dripper device coupled to a branched water distribution network

Study on Measurement of Penstock Head Loss for Hydropower Station with Multiple Units Per Penstock

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