Numerical studies on fluid flow characteristics through different configurations of spiral casing

Nakkina, Parameswara Rao; Prakash, K. Arul; Kumar, Girish

doi:10.1080/19942060.2016.1149103

Cited by 8 publications

(3 citation statements)

References 32 publications

(38 reference statements)

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“…Comparison of experimental data and numerical results revealed the applicability of CFD in accurate flow modeling. Nakkina et al (Rao Nakkina, Arul Prakash, & Saravana Kumar, 2016) used CFD for modeling the flow of fluid in spiral casing with various configurations. Zhang et al (Zhang, Ma, Hong, Yang, & Fang, 2017) used CFD for modeling the flow of axial piston pump.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of nanofluid flow inside a root canal

Ghalandari

Koohshahi

Mohamadian

et al. 2019

Engineering Applications of Computational Fluid Mechanics

106

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Silver nano particles have antimicrobial property which makes them appropriate for disinfection. Due to their antimicrobial feature, these particles are applicable for root canal irrigation. Fluid flow inside root canal and its appropriate circulation results in more efficient removal of microorganisms. Due to the very small dimensions of a root canal, performing experimental research is very difficult to identify the phenomena occurring in the root canal; therefore, numerical investigation will be very helpful to gain appropriate insight into the flow features of a root canal during irrigation for disinfection. Computation Fluid Dynamic (CFD) can be employed to numerically simulate the flow of irrigants inside the root canal. In the present study, the flow of Ag/water nanofluid in the root canal is numerically modeled. In order to evaluate the impact of height of injection and nanofluid concentration, two heights and concentrations are considered and compared. According to the results, lower injection height is more favorable due to better circulation of an irrigant in the root canal. Moreover, increase in the concentration of the nanofluid leads to reduction in maximum velocity of the fluid; which is attributed to higher increase in dynamic viscosity in comparison with the density. Velocity and wall shear stress contours in various cases are represented to gain better insight into the irrigant motion inside the canal. According to the results of simulation, wall shear stress of the root canal increases by increment in the concentration of the nanofluid and volumetric flow rate of the irrigants.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of nanofluid flow inside a root canal

Ghalandari

Koohshahi

Mohamadian

et al. 2019

Engineering Applications of Computational Fluid Mechanics

106

View full text Add to dashboard Cite

show abstract

“…However, the differences in the obtained water velocities were not significant. Nakkina et al [6,7] numerically investigated fluid flow characteristics of accelerated, free-vortex and decelerated types of spiral casings with different aspect ratios to obtain optimal design regarding spiral velocity coefficient, total pressure loss and average radial velocity. Desai et al [8] compared the hydraulic performance of spiral casings with circular and elliptical cross-sections, respectively, designed for high-head Francis turbines.…”

Section: Introductionmentioning

confidence: 99%

Automated hydraulic design procedure for a Francis turbine spiral casing

Lazarevikj

Markov

2022

IOP Conf. Ser.: Earth Environ. Sci.

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The spiral casing of a Francis turbine distributes the water from the penstock to the stay and guide vanes circumferentially and uniformly, which is important for achieving the required flow conditions at the runner entrance. Moreover, the spiral casing is supposed to provide the required inlet velocity in front of the stay vanes and create minimal hydraulic losses. The dimensions and shape of the spiral casing depend on the hydraulic and energy parameters of the turbine. A calculation methodology for a Francis spiral casing hydraulic design is presented in this paper. The methodology developed is based on the main condition to achieve a uniform water flow rate into the stay vanes system and the wicket gate over the entire perimeter. The free vortex flow theory is implemented in this research, where the design is based on the law of constant velocity moment. The parametric definition of the spiral casing makes the geometries generated for certain input combinations suitable for numerical analysis using commercially available Computational Fluid Dynamics (CFD) software. The calculation procedure can be used for any set of energy and geometry turbine parameters, such as water discharge, angle of streamline departing from the spiral casing, and stay ring diameter and height. The automated approach integrating MATLAB and ANSYS Workbench capabilities is presented as a spiral casing design tool. The product is a design solution proposed on basis of the turbine parameters. The spiral casing geometry generation is followed by a CFD analysis. Considering input parameters of different existing Francis turbines, the spiral casing is redesigned accordingly. One of the obtained spiral casings geometry is numerically tested. The results show that the uniform discharge distribution is achieved. The automation of the design procedure allows further optimization based on chosen input parameters.

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“…The radial coordinate is denoted by r, and the angular coordinate by θ . f(r,θ ) presents the turbulence characteristic values at the specific place of targeted coordinate point (Nakkina, Arul Prakash, & Saravana Kumar, 2016). Thereafter the averaged value of turbulence characteristics T characteristic can be calculated as:…”

Section: Cfd Simulations and Actual Awj Grindingmentioning

confidence: 99%

Fuzzy prediction of AWJ turbulence characteristics by using typical multi-phase flow models

Liang

Shan

Liu

et al. 2017

Engineering Applications of Computational Fluid Mechanics

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For the purpose of improving the working performance of AWJ (Abrasive waterjet) grinding in actual machining, and revealing the unknown influence mechanism of waterjet machining prediction, this research conducted a theoretical and experimental investigation concerning with the influences caused by multi-phase flow models, on the fuzzy prediction of turbulence characteristics. First, typical flow models describing the abrasive waterjet were presented and enunciated; Second, a series of turbulence characteristics were defined to quantitatively demonstrate the waterjet flow, which are responsible for the actual performances of AWJ grinding in the contact zone; Then a new fuzzy prediction system equipped with logic protocols was established and introduced to predict turbulence characteristics based upon the machining parameters by employing different flow models, therefore a set of quantified prediction results generated from the CFD (Computational Fluid Dynamics) simulation, orthogonal experiments and actual measurements can be obtained and distinguished systematically. Through a detailed performance analysis with benchmark indexes and prediction comparisons, the theoretical superiorities and specific applications of these flow models were fully discussed and then an integrated conclusion assessing their inherent influence mechanism was acquired. Based on these innovative achievements, the instantaneous machining inspection or parameter optimization in AWJ grinding process can be facilitated, simultaneously the new research ideas aimed at waterjet monitoring or grinding improvements can be presented as well. ARTICLE HISTORY

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Numerical studies on fluid flow characteristics through different configurations of spiral casing

Cited by 8 publications

References 32 publications

Numerical simulation of nanofluid flow inside a root canal

Numerical simulation of nanofluid flow inside a root canal

Automated hydraulic design procedure for a Francis turbine spiral casing

Fuzzy prediction of AWJ turbulence characteristics by using typical multi-phase flow models

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