Detailed Hydrodynamic Study for Performance Optimization of a Combined Lift and Drag-Based Modified Savonius Water Turbine

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Mithinga Basumatary ◽  
Agnimitra Biswas ◽  
Rahul Dev Misra
Keyword(s):  
Performance Optimization ◽  
Operating Conditions ◽  
Hydrodynamic Performance ◽  
Design Parameters ◽  
Ansys Fluent ◽  
Orthogonal Experiments ◽  
Water Turbine ◽  
Hydrodynamic Study ◽  
Lift And Drag ◽  
Power Curves

Abstract A combined lift and drag (CLD) Savonius water turbine is an advanced form of Savonius water turbine that has higher efficiency than the latter. However, its detailed hydrodynamic performance optimization is still unexplored, which is important for its possible future commercialization. The objective of the present work is to perform a detailed hydrodynamic study for performance optimization of the CLD Savonius water turbine at low water speed (characteristic of river stream current) under different design and operating conditions. A parametric optimization using orthogonal experiments is first done to obtain the optimized values of all the contributing design parameters. It is then followed by a detailed computational fluid dynamics (CFD) investigation using ansys fluent software to optimize the hydrodynamic performance of the turbine at the selected design conditions under different operating tip speed ratios (TSRs). Detailed fluidic behaviors including boundary layer features, blade loading, and vorticity structures of the turbine are explored to obtain important performance insights, and power curves of the improved CLD design are also obtained. It is found that the optimized CLD Savonius water turbine has higher hydrodynamic performance than the earlier design of this turbine with a maximum coefficient of power obtained as 0.29 at TSR 0.8.

scholarly journals Thermal Energy Recovery from a Grid Connected Photovoltaic-Thermal (PVT) System Using Water as Working Fluid

2018 ◽  
Vol 7 (4.36) ◽  
pp. 389
Author(s):  
Alhassan Salami Tijani ◽  
Amer Farhan Bin Md Tahir ◽  
Jeeventh Kubenthiran ◽  
Baljit Singh Bhathal Singh
Keyword(s):  
System Design ◽  
Thermal Efficiency ◽  
Energy Recovery ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Geometrical Configuration ◽  
Ansys Fluent ◽  
Design Concepts ◽  
Pressure Distributions

A Photovoltaic Thermal collector (PVT) is a combination of Photovoltaic (PV) and Thermal (T) collector. Many studies have tried to improve the electrical efficiency and thermal efficiency of this PVT system. The efficiency is influenced by many system design parameters and operating conditions such as the absorber temperature, velocity and pressure distributions. In this study, two new design concepts of absorber configuration of thermal collector have been investigated. This study also provides an important opportunity to advance the understanding of the effect of different geometrical configuration on the performance of the absorber.  Simulations were performed using ANSYS FLUENT 16.0 for both absorbers to determine the best absorber design that gives the highest thermal efficiency. Based on the simulations performed, perpendicular serpentine absorber proved to be the best design with the higher thermal efficiency of 56.45%.    

Development of Friction Drive Transmission

2005 ◽  
Vol 127 (4) ◽  
pp. 857-864 ◽  
Author(s):  
Xiaolan Ai ◽  
Matthew Wilmer ◽  
David Lawrentz
Keyword(s):  
Friction Coefficient ◽  
Performance Optimization ◽  
Operating Conditions ◽  
Elastic Support ◽  
Outer Ring ◽  
Design Parameters ◽  
Fe Model ◽  
Frictional Contacts ◽  
Actual Operating ◽  
Wide Range

A cylindrical friction drive was developed for electric oil pump applications. It was comprised of an outer ring, a sun roller, a loading planet, two supporting planets, and a stationary carrier. The sun roller was set eccentric to the outer ring to generate a wedge gap that facilitates a torque actuated loading mechanism for the friction drive. The loading planet was properly assembled in the wedge gap and elastically supported to the carrier. By altering the stiffness ratio of the elastic support to contact, the actual operating friction coefficient of the friction drive can be changed regardless of the wedge angle to suit for performance requirement. This provided a greater freedom for design and performance optimization. Design analysis was presented and a FE model was developed to quantify design parameters. Prototypes of the friction drive were fabricated and extensive testing was conducted to evaluate its performance. Results indicated the performance of the friction drive far exceeded the design specifications in speed, torque, and power ratings. The friction drive offered a consistent smooth and quiet performance over a wide range of operating conditions. It was capable of operating at an elevated speed of up to 12 000 rpm with adequate thermal characteristics. The friction drive demonstrated a peak efficiency above 97%. Results confirmed that the stiffness of the elastic support has an important impact on performance. The elastic support stiffness, in conjunction with the contact stiffness, determines the actual operating friction coefficient at the frictional contacts.

scholarly journals Parametric Study and Design Optimization ....

10.29007/lbz2 ◽  
2018 ◽  
Author(s):  
Vijaypratap R. Singh ◽  
Mahesh J. Zinzuvadia ◽  
Saurin Sheth ◽  
Ruchir J. Desai
Keyword(s):  
Orthogonal Array ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Impeller Blade ◽  
Cad Modelling

To improve the hydrodynamic performance of the centrifugal pump, in present work a DOE technique Taguchi L9 orthogonal array experiment was carried out to optimize the impeller design parameters. The Navier-Stokes equations for three-dimensional steady flow is solved by computational fluid dynamics (CFD) code. The experimental test result of the original pump was compared with the data predicted from the numerical simulation. The comparison shows the closeness of predicted values with the experimental values, leads to validation of the numerical model under the specific range of operating conditions. Four geometric parameters of impeller were chosen as the variable factors viz. Number of blade, Impeller blade outlet angle, Impeller blade Inlet angle and Impeller blade wrapping angle. According to L9 orthogonal array, nine impellers were modelled using CAD modelling software and CFD analysis is carried out using ANSYS CFX. The impellers were equipped with the same volute during all the simulations. The modelled impellers were simulated by the same numerical method, which has been validated. The best parametric combination for higher efficiency is analysed finally. Results show the improvement of 4.25% higher efficiency compared with the original pump. The geometry selected for this model may be the best one to get the maximum efficiency for such pumps.

CARBON CAPTURE AND STORAGE ENERGY CONSUMPTION AND PERFORMANCE OPTIMIZATION USING METAMODELS AND RESPONSE SURFACE METHODOLOGY

2021 ◽  
pp. 1-28
Author(s):  
Ali Allahyarzadeh-Bidgoli ◽  
Nayereh Hamidishad ◽  
Jurandir Itizo Yanagihara
Keyword(s):  
Power Consumption ◽  
Co2 Emissions ◽  
Performance Optimization ◽  
Operating Conditions ◽  
Design Parameters ◽  
Separation Performance ◽  
Co2 Removal ◽  
Operating Pressure ◽  
Heating And Cooling ◽  
And Storage

Abstract Oil and gas industries have high carbon dioxide (CO2) emissions, which is a great environmental concern. Monoethanolamine (MEA) is widely used as a solvent in CO2 capture and storage (CCS) systems. The challenge is that MEA–CCS itself is an energy-intensive process that requires optimum configuration and operation, and numerous design parameters and heat demands must be considered. Thus, the current work evaluates the energy distributions and CO2 removal efficiency of a CCS installed in floating production storage and offloading units under different operating conditions of a power- and heat-generation hub. The optimization procedures are implemented using highly accurate surrogate models for the following responses: 1) overall power consumption of CCS, 2) CCS separation performance, and 3) CCS heating and cooling demands. The input variables considered in the present research include the following: 1) the exhaust gas compositions and mass flow rate, 2) the operating pressure and temperature parameters of CCS and the injection compression unit, 3) the structural parameters of absorber and stripper columns, and 4) MEA solution parameters. The optimum CCS configuration significantly reduces the total heating and cooling demands by 62.77% (7 × 106 kW) and the overall power consumption by 8.65 % (1.8 MW), and it increases the CCS separation performance by 4.46% (97.46%) and mitigates the CO2 emissions of proper CCS by 1.02 t/h compared with conventional operating conditions.

Multidimensional Numerical Simulations of Reacting Flow in a Non-Premixed Rotating Detonation Engine

2019 ◽  
Author(s):  
Pinaki Pal ◽  
Gaurav Kumar ◽  
Scott A. Drennan ◽  
Brent A. Rankin ◽  
Sibendu Som
Keyword(s):  
Detonation Wave ◽  
Performance Optimization ◽  
Design Space Exploration ◽  
Operating Conditions ◽  
Air Injection ◽  
Design Parameters ◽  
Cfd Model ◽  
Rotating Detonation Engine ◽  
Detonation Engine ◽  
Rotating Detonation

Abstract Over the last two decades, detonation based propulsion has received a great deal of attention as a potential means to achieve significant improvement in the performance of air-breathing and rocket engines. Detonative combustion mode is particularly interesting due to the resulting pressure gain from reactants to products, faster heat release, decreased entropy generation, more available work and higher thrust compared to conventional deflagrative combustion. Rotating detonation engine (RDE) is one such novel combustor concept. Realistic RDE configurations utilize separate fuel and air injection schemes, hence are not perfectly premixed. Moreover, RDE performance is governed by a large number of design parameters and operating conditions. In this context, computational fluid dynamics (CFD) has the potential to enhance the understanding of RDE combustion and aid future development/optimization of this technology. In the present work, a CFD model was developed to simulate a representative non-premixed RDE combustor. Unsteady Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for the full combustor geometry (including the separate fuel and air injection ports), with hydrogen as fuel and air as the oxidizer. Adaptive mesh refinement (AMR) was incorporated to achieve a trade-off between model accuracy and computational expense. A finite-rate chemistry model along with a 10-species detailed kinetic mechanism was employed to describe the H2-Air combustion chemistry. Two operating conditions were simulated, corresponding to the same global equivalence ratio of unity but different fuel and air mass flow rates. For both conditions, the capability of the model to capture the essential detonation wave dynamics was assessed. A validation study was performed against experimental data available on detonation wave frequency/height, reactant fill height, oblique shock angle, axial pressure distribution in the channel, and fuel/air plenum pressure. The CFD model predicted the sensitivity of these wave characteristics to the operating conditions with good accuracy, both qualitatively and quantitatively. The present CFD model offers a potential capability to perform rapid design space exploration and/or performance optimization studies for realistic full-scale RDE configurations.

scholarly journals Effect of Mesh Type on Numerical Computation of Aerodynamic Coefficients of NACA 0012 Airfoil

2021 ◽  
Vol 87 (3) ◽  
pp. 31-39
Author(s):  
Mostafa Abobaker ◽  
Sogair Addeep ◽  
Lukmon O Afolabi ◽  
Abdulhafid M Elfaghi
Keyword(s):  
Numerical Computation ◽  
Unstructured Mesh ◽  
Subsonic Flow ◽  
Momentum Conservation ◽  
Operating Conditions ◽  
Computational Method ◽  
Governing Equations ◽  
Ansys Fluent ◽  
Lift And Drag ◽  
Naca 0012

Mesh type and quality play a significant role in the accuracy and stability of the numerical computation. A computational method for two-dimensional subsonic flow over NACA 0012 airfoil at angles of attack from 0o to 10o and operating Reynolds number of 6×106 is presented with structured and unstructured meshes. Steady-state governing equations of continuity and momentum conservation are solved and combined with k-v shear stress transport (SST-omega) turbulence model to obtain the flow. The effect of structured and unstructured mesh types on lift and drag coefficients are illustrated. Calculations are done for constant velocity and a range of angles of attack using Ansys Fluent CFD software. The results are validated through a comparison of the predictions and experimental measurements for the selected airfoil. The calculations showed that the structured mesh results are closer to experimental data for this airfoil and under studied operating conditions.

Design Optimization of a Wearable Artificial Pump-Lung Device With Computational Modeling

2012 ◽  
Vol 6 (3) ◽  
Author(s):  
M. Ertan Taskin ◽  
Tao Zhang ◽  
Katharine H. Fraser ◽  
Bartley P. Griffith ◽  
Zhongjun J. Wu
Keyword(s):  
Design Optimization ◽  
Performance Optimization ◽  
Hollow Fiber Membrane ◽  
Fluid Dynamic ◽  
Operating Conditions ◽  
Design Parameters ◽  
Centrifugal Impeller ◽  
Damage Potential ◽  
Cardiopulmonary Support

The heart-lung machine has commonly been used to replace the functions of both the heart and lungs during open heart surgeries or implemented as extracorporeal membrane oxygenation (ECMO) to provide cardiopulmonary support of the heart and lungs. The traditional heart-lung system consists of multiple components and is bulky. It can only be used for relatively short-term support. The concept of the wearable artificial pump-lung is to combine the functions of the blood pumping and gas transfer in a single, compact unit for cardiopulmonary or respiratory support for patients suffering from cardiac failure or respiratory failure, or both, and to allow patients to be ambulatory. To this end, a wearable artificial lung (APL) device is being developed by integrating a magnetically levitated centrifugal impeller with a hollow fiber membrane bundle. In this study, we utilized a computational fluid dynamics based performance optimization with a heuristic scheme to derive geometrical design parameters for the wearable APL device. The configuration and dimensions of the impeller and the diffuser, the required surface area of fiber membranes and the overall geometrical dimensions of the blood flow path of the APL device were considered. The design optimization was iterated based on the fluid dynamic objective parameters (pressure head, pressure distribution, axial force acting on the impeller, shear stress), blood damage potential (hemolysis and platelet activation), and mass transfer (oxygen partial pressure and saturation). Through the design optimization, an optimized APL device was computationally derived. A physical prototype of the designed APL device was fabricated and tested in vitro. The experimental data showed that the optimized APL can provide adequate blood pumping and oxygen transfer over the range of intended operating conditions.

scholarly journals Three-Bladed Horizontal Axis Water Turbine Simulations with Free Surface Effects

2021 ◽  
Vol 26 (3) ◽  
pp. 187-197
Author(s):  
L. Rodríguez ◽  
A. Benavides-Moran ◽  
S. Laín
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Surface Dynamics ◽  
Two Phase ◽  
Ansys Fluent ◽  
Hydrokinetic Turbine ◽  
Water Turbine ◽  
Free Surface Dynamics

Abstract The water level above a hydrokinetic turbine is likely to vary throughout the season and even along the day. In this work, the influence of the free surface on the performance of a three bladed horizontal-axis turbine is explored by means of a three-dimensional, transient, two-phase flow computational model implemented in the commercial CFD software ANSYS Fluent 19.0. The k – ω SST Transition turbulence model coupled with the Volume of Fluid (VOF) method is used to track the air-water interface. The rotor diameter is D = 0 8m. Two operating conditions are analyzed: deep tip immersion (0.55D) and shallow tip immersion (0.19D). Three tip speed ratios are evaluated for each immersion. Simulation results show a good agreement with experimental data reported in the literature, although the computed torque and thrust coefficients are slightly underestimated. Details of the free surface dynamics, the flow past the turbine and the wake near the rotor are also discussed.

scholarly journals Modeling and Performance Optimization of an Irreversible Two-Stage Combined Thermal Brownian Heat Engine

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 419
Author(s):  
Congzheng Qi ◽  
Zemin Ding ◽  
Lingen Chen ◽  
Yanlin Ge ◽  
Huijun Feng
Keyword(s):  
Power Output ◽  
Performance Optimization ◽  
External Load ◽  
Thermal Contact ◽  
Heat Engine ◽  
Design Parameters ◽  
Load Effect ◽  
Heat Engines ◽  
Heat Leakage ◽  
Steady Current

Based on finite time thermodynamics, an irreversible combined thermal Brownian heat engine model is established in this paper. The model consists of two thermal Brownian heat engines which are operating in tandem with thermal contact with three heat reservoirs. The rates of heat transfer are finite between the heat engine and the reservoir. Considering the heat leakage and the losses caused by kinetic energy change of particles, the formulas of steady current, power output and efficiency are derived. The power output and efficiency of combined heat engine are smaller than that of single heat engine operating between reservoirs with same temperatures. When the potential filed is free from external load, the effects of asymmetry of the potential, barrier height and heat leakage on the performance of the combined heat engine are analyzed. When the potential field is free from external load, the effects of basic design parameters on the performance of the combined heat engine are analyzed. The optimal power and efficiency are obtained by optimizing the barrier heights of two heat engines. The optimal working regions are obtained. There is optimal temperature ratio which maximize the overall power output or efficiency. When the potential filed is subjected to external load, effect of external load is analyzed. The steady current decreases versus external load; the power output and efficiency are monotonically increasing versus external load.

A Transient 3D CFD Model of a Progressive Cavity Pump

2016 ◽  
Author(s):  
K. R. Mrinal ◽  
Md. Hamid Siddique ◽  
Abdus Samad
Keyword(s):  
Oil And Gas ◽  
Complex Geometry ◽  
Transient Behavior ◽  
Oil And Gas Industry ◽  
High Viscosity ◽  
Solid Content ◽  
Operating Conditions ◽  
Cfd Model ◽  
Ansys Fluent ◽  
Flow Variables

A progressive cavity pump (PCP) is a positive displacement pump and has been used as an artificial lift method in the oil and gas industry for pumping fluid with solid content and high viscosity. In a PCP, a single-lobe rotor rotates inside a double-lobe stator. Articles on computational works for flows through a PCP are limited because of transient behavior of flow, complex geometry and moving boundaries. In this paper, a 3D CFD model has been developed to predict the flow variables at different operating conditions. The flow is considered as incompressible, single phase, transient, and turbulent. The dynamic mesh model in Ansys-Fluent for the rotor mesh movement is used, and a user defined function (UDF) written in C language defines the rotor’s hypocycloid path. The mesh deformation is done with spring based smoothing and local remeshing technique. The computational results are compared with the experiment results available in the literature. Thepump gives maximum flowrate at zero differential pressure.

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