Application of Wray–Agarwal Turbulence Model in Flow Simulation of a Centrifugal Pump With Semispiral Suction Chamber

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Leilei Ji ◽  
Wei Li ◽  
Weidong Shi ◽  
Ramesh K. Agarwal
Keyword(s):  
Experimental Data ◽  
Centrifugal Pump ◽  
Turbulence Model ◽  
Full Range ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Internal Flow ◽  
Energy Performance ◽  
Operating Conditions

Abstract The Wray–Agarwal (WA) turbulence model is selected to simulate the internal and external characteristics of a centrifugal pump with semispiral suction chamber; the numerical results are compared with the experimental data and computed results predicted by standard k–ε, renormalization group (RNG) k–ε, and shear stress transport (SST) k–ω turbulence models. The results show that the WA model could be effectively used to compute the energy performance of centrifugal pump under full range of operating conditions and gives higher accuracy than other models. Overall, the WA model shows closer similarity to the experimental data and gives more uniform flow field in the impeller region compared to that predicted by other models. In prediction of internal flow fields of the pump, overall the WA model is more accurate and efficient being a one-equation model. The control of undamped eddy viscosity variable R (= k/ω) in WA model does not allow the overestimation of turbulent kinetic energy and turbulent eddy frequency obtained with other models, which leads to its advantage in accurate prediction of both internal and external flow characteristics of centrifugal pump.

Numerical study of the flow field characteristics over a backward facing step using k-kl-ω turbulence model: comparison with different models

2018 ◽  
Vol 15 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Yasser M. Ahmed ◽  
A.H. Elbatran
Keyword(s):  
Experimental Data ◽  
Fluid Mechanics ◽  
Turbulence Model ◽  
Flow Separation ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Numerical Results ◽  
Backward Facing Step ◽  
Content Type ◽  
Case Comparison

Purpose This paper aims to investigate numerically the turbulent flow characteristics over a backward facing step. Different turbulence models with hybrid computational grid have been used to study the detached flow structure in this case. Comparison between the numerical results and the available experiment data is carried out in the present study. The results of the different turbulence models were in a good agreement with the experimental results. The numerical results also concluded that the k-kl-ω turbulence model gave favorable results compared with the experiment. Design/methodology/approach It is very important to study the flow characteristics of detached flows. Therefore, the current study investigates numerically the flow characteristics in backward facing step by using two-, three- and seven-equation turbulence models in the finite volume code ANSYS Fluent. In addition, hybrid grid has been used to improve the capability of the unstructured mesh elements for predicting the flow separation in this case. Comparison between the different turbulence models and the available experimental data was done to find the most suitable turbulence model for simulating such cases of detached flows. Findings The present numerical simulations with the different turbulence models predicted efficiently the flow characteristics over the backward facing step. The transition k-kl-ω gave the best acceptable results compared with experimental data. This is a good concluded remark in the fields of fluid mechanics and hydrodynamics because the phenomenon of flow separation is not easy to be predicted numerically and can affect greatly on the predicted drag of moving bodies in many engineering applications. Originality/value The CFD results of using different turbulence models have been validated with the experimental work, and the results of k-kl-ω proven acceptable with flow characteristics. The results of the current study conclude that the use of k-kl-ω turbulence model will contribute towards a more efficient utilization in the fields of fluid mechanics and hydrodynamics.

An improved turbulence model for predicting unsteady cavitating flows in centrifugal pump

2015 ◽  
Vol 25 (5) ◽  
pp. 1198-1213 ◽  
Author(s):  
Jian Wang ◽  
Yong Wang ◽  
Houlin Liu ◽  
Haoqin Huang ◽  
Linglin Jiang
Keyword(s):  
Centrifugal Pump ◽  
Turbulence Model ◽  
Eddy Viscosity ◽  
Turbulent Viscosity ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Content Type ◽  
Cavitation Inception ◽  
Cavitation Performance ◽  
Unsteady Rans

Purpose – The purpose of this paper is to study the unsteady caivitating flows in centrifugal pump, especially for improving the turbulence model to obtain highly resolution results-capable of predicting the cavitation inception, shedding off and collapse procedures. Design/methodology/approach – Both numerical simulations and experimental visualizations were performed in the present paper. An improved RCD turbulence models was proposed by considering three corrected methods: the rotating corrected method, the compressible corrected method and the turbulent viscosity corrected method. Unsteady RANS computations were conducted to compare with the experiments. Findings – The comparison of pump cavitation performance showed that the RCD turbulence model obtained better performance both in non-cavitation and cavitation conditions. The visualization of the cavitation evolution was recorded to validate the unsteady simulations. Good agreement was noticed between calculations and visualizations. It is indicated the RCD model can successfully capture the bubbles detachment and collapse at the rear of the cavity region, since it effectively reduces the eddy viscosity in the multiphase region of liquid and vapor. Furthermore, the eddy viscosity, the instantaneous pressure and density distribution were investigated. The effectiveness of the compressibility was found. Meanwhile, the influence of the rotating corrected method on prediction was explored. It is found that the RCD model solved more unsteady flow characteristics. Originality/value – The current work presented a turbulence model which was much more suitable for predicting the cavitating flow in centrifugal pump.

scholarly journals Numerical Simulation of Internal Flow Field of Self-Designed Centrifugal Pump

2021 ◽  
Vol 2097 (1) ◽  
pp. 012017
Author(s):  
Xin Wang ◽  
Jun Zhang ◽  
Zongshun Li
Keyword(s):  
Centrifugal Pump ◽  
Turbulence Model ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Suction Surface ◽  
Sst Turbulence Model ◽  
Rng Turbulence Model ◽  
Pump Cavity ◽  
Gas Volume

Abstract The two self-designed of centrifugal pump with small vane and centrifugal pump without small vane were simulated numerically to select a centrifugal pump with higher efficiency. The internal flow characteristics of the centrifugal pump was simulated by using Reynolds time-averaged N-S equation and RNG turbulence model to obtain pressure and velocity distribution and the cavitation characteristics were simulated by using SST turbulence model and Schnerr-Sauer cavitation model to obtain the gas volume fraction distribution. The results show that at the same flow rate, the change of velocity in the pump cavity of centrifugal pump with vane is smoother and the gas volume is less, but the back-flow is aggravated near the small vane, especially when interacting with the tongue, and a large amount of gas is generated at the suction surface of the small vane. In addition, the efficiency of centrifugal pump without vane is higher than that of centrifugal pump with vane, which provides a basis for the structural optimization of centrifugal pump.

Performance improvement of a high-speed aero-fuel centrifugal pump through active inlet injector

2020 ◽  
pp. 095441002096096
Author(s):  
Jia Li ◽  
Xin Wang ◽  
Wancheng Wang ◽  
Yue Wang
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Turbulence Model ◽  
High Speed ◽  
Flow Direction ◽  
Active Flow Control ◽  
Turbulence Models ◽  
Internal Flow ◽  
Geometrical Parameters ◽  
Centrifugal Pumps

This paper presents a high-speed aero-fuel centrifugal pump with an active inlet injector for an aero-engine aiming at regulating the internal flow field and improving overall hydraulic performance. Unlike most of the existing centrifugal pumps for aero-engines, an injector is designed and integrated with the pump to accomplish the active flow control. Firstly, by employing the energy equation in the pump, reasonable geometrical parameters of the injector are calculated. Then, a validation study is conducted with three known turbulence models, showing that simulations with the RNG κ- ε turbulence model can accurately predict the head and efficiency of the experimental pump. Finally, simulation results with the determined turbulence model are discussed. The results show that the static pressure is uniformly distributed inside the impeller, the volute and the injector. The flow field is significantly ameliorated by improving the pressure inside the suction pipe and controlling the flow direction via the injector. Furthermore, the head and efficiency of the designed pump with an active inlet injector are improved compared to the one without an injector.

Two-dimensional numerical investigation of film cooling by a cool jet injected at various angles for different blowing ratios

2008 ◽  
Vol 222 (7) ◽  
pp. 1215-1224 ◽  
Author(s):  
S Bayraktar ◽  
T Yilmaz
Keyword(s):  
Experimental Data ◽  
Renormalization Group ◽  
Numerical Investigation ◽  
Turbulence Model ◽  
Film Cooling ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Cooling Efficiency ◽  
Two Dimensional ◽  
Transverse Jet

This paper presents the thermal and flow characteristics of a cold transverse jet, injected at five different angles (α = 30°, 45°, 60°, 75°, and 90°) into a hot crossflow with four different blowing ratios ( M = 0.1, 0.3, 0.5, and 0.8). Three turbulence models, namely, standard k−∊, renormalization group (RNG) k−∊, and realizable k−∊ are tested for obtaining the accurate turbulence model to predict the effectiveness of film cooling. The tested turbulence models were compared with available experimental data in the literature. The results evinced that the RNG k−∊ turbulence model is the most appropriate among the three. It is also observed that maximum cooling efficiency is obtained at α = 30° and M = 0.8.

Numerical Simulation and Impeller Optimization of a Centrifugal Pump

2012 ◽  
Vol 472-475 ◽  
pp. 2195-2198 ◽  
Author(s):  
Shao Ping Zhou ◽  
Pei Wen Lv ◽  
Xiao Xia Ding ◽  
Yong Sheng Su ◽  
De Quan Chen
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Centrifugal Pump ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Three Dimensional Flow ◽  
Field Simulation ◽  
Simulation Results

The three-dimensional flow field simulation of a centrifugal pump was presented by using commercial CFD code. In order to study the most suitable turbulence model, the three known turbulence models of Standard k-ε, RNG k-ε, Realizable k-ε were applied to simulate the flow field of the MJ125-100 centrifugal pump and predict the performance of the pump. The simulation results of head and efficiency were compared with available experimental data, and the comparison showed that the result of the numerical simulation by RNG k-ε model had the best agreement. Additionally, the effect of number of blades on the efficiency of pump was studied. The number of blades was changed from 4 to 7. The results showed that the impeller with 7 blades had the highest efficiency.

scholarly journals Analysis of Flow Characteristics and Effects of Turbulence Models for the Butterfly Valve

2021 ◽  
Vol 11 (14) ◽  
pp. 6319
Author(s):  
Sung-Woong Choi ◽  
Hyoung-Seock Seo ◽  
Han-Sang Kim
Keyword(s):  
Turbulence Model ◽  
Dissipation Rate ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Flow Properties ◽  
Nominal Diameter ◽  
Large Pressure ◽  
Sst Model ◽  
Turbulence Effect ◽  
Valve Opening

In the present study, the flow characteristics of butterfly valves with different sizes DN 80 (nominal diameter: 76.2 mm), DN 262 (nominal diameter: 254 mm), DN 400 (nominal diameter: 406 mm) were numerically investigated under different valve opening percentages. Representative two-equation turbulence models of two-equation k-epsilon model of Launder and Sharma, two-equation k-omega model of Wilcox, and two-equation k-omega SST model of Menter were selected. Flow characteristics of butterfly valves were examined to determine turbulence model effects. It was determined that increasing turbulence effect could cause many discrepancies between turbulence models, especially in areas with large pressure drop and velocity increase. In addition, sensitivity analysis of flow properties was conducted to determine the effect of constants used in each turbulence model. It was observed that the most sensitive flow properties were turbulence dissipation rate (Epsilon) for the k-epsilon turbulence model and turbulence specific dissipation rate (Omega) for the k-omega turbulence model.

Calculation of Flow in Mixing Vessels With Various Turbulence Models

Volume 4 ◽  
2004 ◽  
Author(s):  
Branislav Basara ◽  
Ales Alajbegovic ◽  
Decan Beader
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Turbulence Model ◽  
Unstructured Grids ◽  
Turbulence Models ◽  
Cfd Applications ◽  
Volume Method ◽  
Rushton Impeller

The paper presents calculations of flow in a mixing vessel stirred by a six-blade Rushton impeller. Mathematical model used in computations is based on the ensemble averaged conservation equations. An efficient finite-volume method based on unstructured grids with rotating sliding parts composed of arbitrary polyhedral elements is used together with various turbulence models. Besides the standard k-ε model which served as a reference, k-ε-v2 model (Durbin, 1995) and the recently proposed hybrid EVM/RSM turbulence model (Basara & Jakirlic, 2003) were used in the calculations. The main aim of the paper is to investigate if more advanced turbulence models are needed for this type of CFD applications. The results are compared with the available experimental data.

Turbulence Model Influence on Numerical Investigation of Transonic Axial Compressor Rotor

2011 ◽  
Vol 308-310 ◽  
pp. 1519-1522
Author(s):  
Fang Xie ◽  
Chang Jiang Liu ◽  
You Jun Wang
Keyword(s):  
Experimental Data ◽  
Numerical Investigation ◽  
Turbulence Model ◽  
Characteristic Curve ◽  
Axial Compressor ◽  
Internal Flow ◽  
Turbulent Model ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Point Forecast

Numerical method using HI and HOH meshing combined B - L turbulent model and S - A turbulent model separately based on the Rotor 37 compressor Rotor was applied to the steady flow. results on pressure characteristic curve, stall point forecast etc were compared with related experimental data. This paper discussed calculation precision influenced by the turbulence model and numerical computation grid. This numerical investigation was basis for subsequent compressor internal flow field study.

scholarly journals 2D Numerical Simulation Study of Airfoil Performance

2021 ◽  
Author(s):  
Nasser Shelil
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Air Temperature ◽  
Wind Turbines ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Ansys Fluent

Abstract. The aerodynamic characteristics of DTU-LN221 airfoil is studied. ANSYS Fluent is used to simulate the airfoil performance with seven different turbulence models. The simulation results for the airfoil with different turbulence models are compared with the wind tunnel experimental data performed under the same operating conditions. It is found that there is a good agreement between the computational fluid dynamics (CFD) predicted aerodynamic force coefficients with wind tunnel experimental data especially with angle of attack between −5° to 10°. RSM is chosen to investigate the flow field structure and the surface pressure coefficients under different angle of attack between −5° to 10°. Also the effect of changing air temperature, velocity and turbulence intensity on lift and drag coefficients/forces are examined. The results show that it is recommended to operate the wind turbines airfoil at low air temperature and high velocity to enhance the performance of the wind turbines.

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