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

doi:10.1080/19942060.2016.1149103

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

Journal Article•DOI•

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

Parameswara Rao Nakkina¹, K. Arul Prakash¹, G. Saravana Kumar¹•Institutions (1)

Indian Institute of Technology Madras¹

29 Mar 2016-Engineering Applications of Computational Fluid Mechanics (Taylor & Francis)-Vol. 10, Iss: 1, pp 296-310

TL;DR: In this paper, the authors proposed an optimum spiral casing configuration by reducing the total pressure loss and increasing the spiral velocity coefficient and average radial velocity at the exit of spiral casing, which is based on the streamline upwind Petrov-Galerkin (SUPG) finite-element method.

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Abstract: The design of optimum spiral casing configuration is a difficult task and a big challenge in the field of turbomachinery. Computational fluid dynamics (CFD) analysis of fluid flow characteristics in a turn around spiral casing plays an important role in its design. The objective in this study is to propose an optimum spiral casing configuration by reducing the total pressure loss and increasing the spiral velocity coefficient and average radial velocity at the exit of spiral casing. For this, three different configurations of spiral casing, viz. accelerated, decelerated and free vortex type, with different aspect ratios (ARs) are numerically simulated. A Eulerian velocity-correction method based on the streamline upwind Petrov–Galerkin (SUPG) finite-element method is employed to solve complete Reynolds-averaged Navier–Stokes (RANS) equations governing fluid flow characteristics. The results show that the average radial velocity along the exit of spiral casings is more for elliptical cross-sectiona...

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Numerical simulation of nanofluid flow inside a root canal

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Mohammad Ghalandari¹, Elaheh Mirzadeh Koohshahi², Fatemeh Mohamadian³, Shahabbodin Shamshirband⁴, Kwok Wing Chau⁵ - Show less +1 more•Institutions (5)

Sharif University of Technology¹, Amirkabir University of Technology², Shahid Beheshti University of Medical Sciences and Health Services³, Ton Duc Thang University⁴, Hong Kong Polytechnic University⁵

01 Mar 2019-Engineering Applications of Computational Fluid Mechanics

TL;DR: In this article, the authors have shown that 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.

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Abstract: 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...

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101 citations

Journal Article•DOI•

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

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Liang Zhongwei¹, Shan Shiyin¹, Liu Xiaochu¹, Yiheng Wen¹•Institutions (1)

Guangzhou University¹

02 Feb 2017-Engineering Applications of Computational Fluid Mechanics

TL;DR: 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 paper as discussed by the authors has been published.

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Abstract: 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 re...

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16 citations

Journal Article•DOI•

Design of Spiral Casing of Francis Turbine for Micro Hydro Applications

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Dadi Ram Dahal¹, Sailesh Chitrakar¹, A. Kapali¹, Bhola Thapa¹, Hari Prasad Neopane¹ - Show less +1 more•Institutions (1)

Kathmandu University¹

01 Jun 2019

TL;DR: In this paper, the authors design the best configuration of cross section of spiral casing which have a very minimal pressure loss and can provide required inlet flow condition for stay vanes.

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Abstract: Spiral casing is an important component of Francis turbine for even distribution of kinetic and potential energy of water so as to achieve the required reaction for better performance of the runner. Optimal design and analysis of spiral configuration is challenging, especially when the turbine is operating in a low head range due to the necessity of a large cross-sectional area of the casing to accumulate the large flow. The main objective of this study is to design the best configuration of cross section of spiral casing which have a very minimal pressure loss and can provide required inlet flow condition for stay vanes. For this, spiral casing configurations following free-vortex theory with different cross sections i.e. circular, trapezoidal and square are designed and analysed numerically. Pressure, radial and tangential velocity distributions are compared for different cross section of spiral casing suitable for micro hydro applications. Considering the ease of manufacturing, flexibility of dimension adjustments and comparable performance with that of the circular spiral casing, trapezoidal casing is found to be an appropriate alternative for such applications.

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7 citations

Journal Article•DOI•

Steady and Unsteady Forced Convective Heat Transfer Analysis in 180 Degree Bend

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Chandramouli Koushik¹, Karaiyan Arul Prakash¹•Institutions (1)

Indian Institute of Technology Madras¹

15 Dec 2020-Heat Transfer Engineering

TL;DR: In this article, numerical studies on fluid flow and heat transfer through a two-dimensional 180-degree sharp bend are performed using an in-house code based on streamline upwind Petrov-Galerkin finite element meth.

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Abstract: Numerical studies on fluid flow and heat transfer through a two-dimensional 180-degree sharp bend are performed using an in-house code based on streamline upwind Petrov-Galerkin finite element meth...

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5 citations

Journal Article•DOI•

Improvement of flow behavior in the spiral casing of Francis hydro turbine model by shape optimization

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Ujjwal Shrestha¹, Young-Do Choi¹•Institutions (1)

Mokpo National University¹

01 Sep 2020-Journal of Mechanical Science and Technology

TL;DR: In this paper, the shape of a spiral casing is optimized based on a steady-state flow analysis and numerical optimization is performed using response surface methodology (RSM) and multiobjective genetic algorithm (MOGA).

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Abstract: A spiral casing is an important component of Francis hydro turbine for the even distribution of kinetic energy along the stay and guide vanes. The fluid flow around the runner is dependent on the flow condition of a spiral casing. The shape of the casing plays an important role in proper flow distribution. In this study, the optimization of the shape of a spiral casing is based on a steady-state flow analysis. Numerical optimization is performed using response surface methodology (RSM) and multiobjective genetic algorithm (MOGA). The flow uniformity and head loss in the spiral casing are selected as objectives for the optimal design of the spiral casing. The optimal design is selected from the solution acquired by RSM and MOGA. Moreover, the flow characteristics in the initial and optimal designs of the spiral casing are compared. The flow conditions in the optimal design improve significantly with the optimal design of the spiral casing. Thus, the inlet conditions for the stay vane are improved with the optimal design of the spiral casing.

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4 citations

References

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Journal Article•DOI•

The numerical computation of turbulent flows

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Brian Launder¹, D. B. Spalding¹•Institutions (1)

Imperial College London¹

01 Sep 1990-Computer Methods in Applied Mechanics and Engineering

TL;DR: In this paper, the authors present a review of the applicability and applicability of numerical predictions of turbulent flow, and advocate that computational economy, range of applicability, and physical realism are best served by turbulence models in which the magnitudes of two turbulence quantities, the turbulence kinetic energy k and its dissipation rate ϵ, are calculated from transport equations solved simultaneously with those governing the mean flow behaviour.

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11,866 citations

Journal Article•DOI•

Numerical Calculation of Time‐Dependent Viscous Incompressible Flow of Fluid with Free Surface

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Francis H. Harlow, J. Eddie Welch

01 Jan 1965-Physics of Fluids

TL;DR: In this paper, a new technique is described for the numerical investigation of the time-dependent flow of an incompressible fluid, the boundary of which is partially confined and partially free The full Navier-Stokes equations are written in finite-difference form, and the solution is accomplished by finite-time step advancement.

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Abstract: A new technique is described for the numerical investigation of the time‐dependent flow of an incompressible fluid, the boundary of which is partially confined and partially free The full Navier‐Stokes equations are written in finite‐difference form, and the solution is accomplished by finite‐time‐step advancement The primary dependent variables are the pressure and the velocity components Also used is a set of marker particles which move with the fluid The technique is called the marker and cell method Some examples of the application of this method are presented All non‐linear effects are completely included, and the transient aspects can be computed for as much elapsed time as desired

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5,841 citations

"Numerical studies on fluid flow cha..." refers methods in this paper

...The solution algorithm uses a Eulerian velocity-correction approach that is based on the projection scheme of Chorin (1967), which was initially developed in a finite-difference context and is also incorporated in the Marker and cell (MAC) method of Harlow and Welch (1982)....
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Journal Article•DOI•

Streamline upwind/Petrov-Galerkin formulations for convection dominated flows with particular emphasis on the incompressible Navier-Stokes equations

[...]

A. N. Brooks¹, Thomas J. R. Hughes•Institutions (1)

AeroVironment¹

01 Sep 1990-Computer Methods in Applied Mechanics and Engineering

TL;DR: In this article, a new finite element formulation for convection dominated flows is developed, based on the streamline upwind concept, which provides an accurate multidimensional generalization of optimal one-dimensional upwind schemes.

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5,157 citations

Journal Article•DOI•

A Numerical Method for Solving Incompressible Viscous Flow Problems

[...]

Alexandre J. Chorin¹•Institutions (1)

Courant Institute of Mathematical Sciences¹

01 Aug 1997-Journal of Computational Physics

TL;DR: In this article, a numerical method for solving incompressible viscous flow problems is introduced, which uses the velocities and the pressure as variables and is equally applicable to problems in two and three space dimensions.

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2,797 citations

"Numerical studies on fluid flow cha..." refers background or methods or result in this paper

...measurements. The spiral casing of a hydraulic turbine is a passage with a 360◦ turn. The function of the spiral casing in a Francis turbine is to distribute the water as evenly as possible to the stay and guide vanes (distributor) and then to the turbine runner. Stay vanes are used to stabilize the flow regime and guide vanes are used to control the flow rate and, consequently, the power generated by the turbine. The flow through the distributor for various boundary conditions with different configurations was analyzed by Dadfar, Firoozabadi, and Ahmadi (2010). Their study revealed that the presence of runner blades under design conditions has minor effects on the pressure field around the stay and guide vane. In an efficiently designed spiral casing, the pressure head of the fluid is available to the runner with minor losses. Therefore, the analysis of fluid flow through a spiral casing with regard to minimum pressure loss is very much essential. Shyy and Vu (1991) conducted a study to predict the fluid flow structure and losses in various sections of the turbine. In their investigation, Reynolds-averaged Navier–Stokes (RANS) equations, closed with the k-ε turbulence model (Launder & Spalding, 1974), were solved for high Reynolds numbers. The energy losses which take place in all the components of hydraulic turbines mainly occur due to flow separation, secondary flow, wall friction, etc. Some experimental studies state that the hydraulic loss in a spiral casing depends on the formation of secondary flow. Flow curvature and viscous forces are the main sources for the generation of secondary flow in spiral casings, as experimentally observed by Kurokawa and Nagahara (1986). The failure of the Dartmouth turbine casing due to the stresses and fracture mechanics caused by fluid hammer was studied by Price (1998)....
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...simulated by L.-X. Zhang, Wang, and Guo (2007) using the large eddy simulation approach. From this study, spatial and temporal distributions of the fully developed turbulence were investigated. The spatial and temporal distribution of the turbulent flow in the blade passage is non-uniform. Flow-induced stresses in a Francis turbine runnerwere numerically analyzed by Saeed,Galybin, and Popov (2010) and Negru, Muntean, Marsavina, SusanResiga, and Pasca (2012). In these studies, the results of large-scale modeling of the water flow and analysis of flow-induced stresses in a Francis turbine runner are...
[...]
...measurements. The spiral casing of a hydraulic turbine is a passage with a 360◦ turn. The function of the spiral casing in a Francis turbine is to distribute the water as evenly as possible to the stay and guide vanes (distributor) and then to the turbine runner. Stay vanes are used to stabilize the flow regime and guide vanes are used to control the flow rate and, consequently, the power generated by the turbine. The flow through the distributor for various boundary conditions with different configurations was analyzed by Dadfar, Firoozabadi, and Ahmadi (2010). Their study revealed that the presence of runner blades under design conditions has minor effects on the pressure field around the stay and guide vane. In an efficiently designed spiral casing, the pressure head of the fluid is available to the runner with minor losses. Therefore, the analysis of fluid flow through a spiral casing with regard to minimum pressure loss is very much essential. Shyy and Vu (1991) conducted a study to predict the fluid flow structure and losses in various sections of the turbine....
[...]
...measurements. The spiral casing of a hydraulic turbine is a passage with a 360◦ turn. The function of the spiral casing in a Francis turbine is to distribute the water as evenly as possible to the stay and guide vanes (distributor) and then to the turbine runner. Stay vanes are used to stabilize the flow regime and guide vanes are used to control the flow rate and, consequently, the power generated by the turbine. The flow through the distributor for various boundary conditions with different configurations was analyzed by Dadfar, Firoozabadi, and Ahmadi (2010). Their study revealed that the presence of runner blades under design conditions has minor effects on the pressure field around the stay and guide vane....
[...]
...simulated by L.-X. Zhang, Wang, and Guo (2007) using the large eddy simulation approach. From this study, spatial and temporal distributions of the fully developed turbulence were investigated. The spatial and temporal distribution of the turbulent flow in the blade passage is non-uniform. Flow-induced stresses in a Francis turbine runnerwere numerically analyzed by Saeed,Galybin, and Popov (2010) and Negru, Muntean, Marsavina, SusanResiga, and Pasca (2012)....
[...]

Journal Article•DOI•

Finite element solution of the unsteady Navier-Stokes equations by a fractional step method

[...]

J. Donea, S. Giuliani, H. Laval, Luigi Quartapelle¹•Institutions (1)

Polytechnic University of Milan¹

01 Apr 1982-Computer Methods in Applied Mechanics and Engineering

TL;DR: In this article, a finite element method is presented for the numerical simulation of time-dependent incompressible viscous flows, based on a fractional step approach to the time integration of the Navier-Stokes equations in which only the incompressibility condition is treated implicitly.

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217 citations