Investigation of Numerical Simulation Parameters on Fluid Flow Around Trash-Racks

Čarija, Zoran; Lučin, Ivana; Lučin, Bože; Grbčić, Luka

doi:10.2507/29th.daaam.proceedings.149

Cited by 4 publications

(4 citation statements)

References 10 publications

(14 reference statements)

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“…As clarified in the previous section, after knowing the different speeds, the power ratings were verified, and the turbine efficiency was estimated using Eqs. (10), (11) and (12). Thus, 𝑃𝑃𝑃𝑃𝑛𝑛 𝐼𝐼 = 23.77 𝑘𝑘𝑘𝑘 y 𝑃𝑃𝑃𝑃𝑛𝑛 𝐼𝐼 = 6.62 𝑘𝑘𝑘𝑘 was used to predict a 𝑃𝑃𝑃𝑃𝑛𝑛 𝑒𝑒𝑐𝑐𝑒𝑒𝐸𝐸𝑡𝑡 = 30.39 𝑘𝑘𝑘𝑘 and a 𝑛𝑛ℎ = 86.3%, therefore, taking into account all the efficiencies, it is established a 𝑃𝑃 𝑠𝑠 = 20.74 𝑘𝑘𝑘𝑘, which is considered to be in compliance with expectations.…”

Section: Hydraulic Designmentioning

confidence: 98%

“…In 2009, a 2D analysis showed an efficiency of 59.8%, for a flow rate of 0.255 m 3 /s and a rotational speed of 428.6 rpm. The analysis of the velocity vectors showed, again, the importance of the flow in the region adjacent to the blades [10]. In 2011, the velocity and pressure fields of the cross flow inside the runner were analyzed to characterize the performance at different velocities.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of the Opening Angle Incidence in Michell-Banki Turbine’s Performance without Guide Blades

Capera,

Marín,

Sandoval

2023

JERA

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Technologies that take advantage of alternative sources, such as Michell-Banki turbines, can improve electric power conditions in rural or non-interconnected areas with low environmental impact, but they need to be further studied to better understand their phenomenology and ways to increase their performance. The numerical evaluation of rotors under specific operating conditions results in efficiency curves for the evaluated prototypes such that devices that take full advantage of the flow conditions of a given location are proposed. Considering the above, the main objective of this work was to design the rotor and the injector of a Michell-Banki turbine and to evaluate it numerically for the conditions of 0.24 m3/s and 18 m of head available at a point with potential energy use in the irrigation district Canal Iguá in Huila - Colombia. The design was made following OLADE recommendations, and the simulations were made utilizing computational fluid dynamics, the k- ω turbulence model was used and the torque was monitored, then the GCI and TCI were calculated to establish the numerical uncertainty of the results. Finally, the numerical curves of efficiency versus rotor speed were created. Both the design and simulation results show that the design is feasible for the operating conditions and meets the expectations of serving for the installation of a 20 kW micro-hydroelectric power plant at the site, but the design predicted an atypically high 86.3% efficiency, while the simulation reported an atypically low 51.8%, being 78% the average reported according to OLADE.

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Section: Hydraulic Designmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Opening Angle Incidence in Michell-Banki Turbine’s Performance without Guide Blades

Capera,

Marín,

Sandoval

2023

JERA

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“…For example, Nascimento et al [54] performed simulations using the LES model with only two rectangular bars in a 2D domain to investigate the vortex shedding frequencies induced by the rack, but they excluded ξ in the analysis. Other researchers, including Ghamry and Katopodis [55], Paul and Adaramola [56], Jeethulakshmi et al [57], and Čarija et al [58], also performed simulations with the number of bars n ranging from 1 to 14, mainly using the RANS approach and 3D domains, and calculated ξ. Typically, the results overestimated ξ compared to the values derived from empirical formulas and previous model tests.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulations of Flow Past Circular Cylinders to Determine Head Loss Coefficients of Circular Bar Trash Racks with Perpendicular Inflow Conditions

Zöschg

2024

Water

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Trash racks installed at hydropower plants cause head losses that reduce energy output. Previous research has thoroughly investigated head losses through both experimental and field studies. However, only a limited number of numerical studies have been performed, which have shown significant simplifications in terms of model complexity. In this study, the head loss coefficients ξ of circular bar trash racks (CBTRs) were analyzed using 3D Large Eddy Simulation (LES). Specifically, a single submerged bar oriented perpendicular to the flow direction was studied under homogeneous inflow conditions while (i) the blocking ratio P was varied between 0.043 and 0.444, and (ii) the flow velocity U was varied between 0.3 and 1.0 m/s. The model parameters were selected primarily based on the extensive literature on flow past circular cylinders, particularly at a Reynolds bar number Reb of 3900. To ensure the validity of the parameters, systematic independence tests were performed, including simulations with three and five bars in the computational domain. The results confirmed the suitability of 3D LES as an appropriate tool to determine ξ of CBTRs. In general, ξ decreased continuously with decreasing P and increased with increasing U when Reb ≥ 3981, which is consistent with comparable flow parameters observed in previous studies of flow past circular cylinders. Notably, the study found that the empirical formulas used for comparison tended to underestimate ξ when P was relatively low. Finally, the potential of the presented approach for future applications was discussed in detail.

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“…Additionally, an algorithm was designed and validated to study nonisothermal two-phase flow with free surface [13]. Research on numerical simulation parameters, geometry and mesh on fluid flow around a large number of trash-racks combinations and comparison with experimental results from literature has been reported recently [14]. An experimental method that can be used for investigation of mixing phenomena in double tee-junctions placed at different distances was reported by Lucin and coworkers.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Boundary Layer Thickness and Drag Coefficients in a Fluid System

Beltrán-Prieto¹,

Kolomaznı́k²

2019

DAAAM Proceedings

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Over the years, many of the most demanding industries have relied on fluid flow analysis and process design to ensure proper operation and to maximize profitability and operational safety. It is well known that many of the fluids used in industrial applications behave in turbulent regime. As a result, clear and proper understanding of parameters such as transitional flow, measurement of instantaneous velocity in a fluid stream, flow behavior at lower and higher velocities inside tubes or pipes and resistance of an object in a fluid environment is important. In the present paper we study the laminar boundary layer on a flat plate and also discuss the case of turbulent flow using integral momentum balance for the boundary layer to obtain a general momentum integral relation after using an empirical or assumed velocity distribution. Furthermore, we determine the boundary layer thickness and discuss two methods to estimate drag coefficient at different distances from the leading edge. Results from the current research can be applied by the industry to model complex parameter dependencies and to estimate and simulate the presence of drag on solids with particular geometrical properties of size and shape.

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Investigation of Numerical Simulation Parameters on Fluid Flow Around Trash-Racks

Cited by 4 publications

References 10 publications

Numerical Study of the Opening Angle Incidence in Michell-Banki Turbine’s Performance without Guide Blades

Numerical Study of the Opening Angle Incidence in Michell-Banki Turbine’s Performance without Guide Blades

Large Eddy Simulations of Flow Past Circular Cylinders to Determine Head Loss Coefficients of Circular Bar Trash Racks with Perpendicular Inflow Conditions

Estimation of Boundary Layer Thickness and Drag Coefficients in a Fluid System

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