scholarly journals Numerical and experimental characterization of splitter blade impact on pump as turbine performance

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042199324
Author(s):  
Daniel Adu ◽  
Jianguo Du ◽  
Ransford O Darko ◽  
Eric Ofosu Antwi ◽  
Muhammad Aamir Shafique Khan
Keyword(s):  
Rotational Speed ◽  
Simulated Data ◽  
Maximum Deviation ◽  
Cfd Simulations ◽  
Flow Rates ◽  
Turbine Performance ◽  
Hydropower Dams ◽  
The Impact ◽  
Good Agreement

Several rivers and streams are available in Africa and Asian regions with great potentials not applicable for constructing large hydropower dams but feasible for small and mini hydro generation. This study strive for investigating the impact of splitter blade on pump as turbine performance considering different speed and flow rates. Two specific centrifugal pump models one with six blades without splitter and another with four blades and four splitters were used for the study. The inlet diameter and outlet diameters of both impellers were 104 mm/116 mm, and 160 mm respectively at a designed flow rate Q = 12.5 m3/h, head H = 16 m, rotational speed n = 1450 rpm and efficiency of 56%, outlet impeller width of 0.006 m, a blade outlet angle of 30° was used for the study. CFD simulations were conducted with the use of k-ε turbulence model. The influence of splitter blade position on the performance of pump as turbine in the selected specific pumps with and without splitter blades has been investigated both experimentally and numerically at three different flow rates and rotational speed. The simulated data were in good agreement with the experimental results, the maximum deviation error between the CFD and test for each model are 5.6%, 2.6%, for the head and efficiency; 7.5% and 3.6% at different flow conditions.

scholarly journals Computational Liquid Dynamic Simulation Mixing Time from Side Inlet Mixer Tank

2021 ◽  
Vol 5 (1) ◽  
pp. 30-40
Author(s):  
Nadia Mumtazah ◽  
Ainurazis Ramadhana Putraninghadi ◽  
Ni'am Nisbatul
Keyword(s):  
Rotational Speed ◽  
Single Phase ◽  
Rotation Speed ◽  
Fluid Dynamic ◽  
Mixing Time ◽  
Flat Bottom ◽  
Geometric Size ◽  
Cfd Method ◽  
The Impact ◽  
Good Agreement

This study aims to investigate the mixing time of the side-entry mixer tank and the influence of the propeller's rotational speed on mixing time by the Computational Fluid Dynamic (CFD) method. The tank's model is a flat-bottom cylinder tank whose diameter is 40 cm with a 6 cm propeller contains three blades. The tracer, HCL 37%, was injected on the water's surface while the propeller's rotation speed is varied 100 rpm, 200 rpm, 300 rpm, and 400 rpm. The simulation process is examined using CFD FLUENT 17.1, with a turbulence model is k-ɛ RNG. Its conditions are single-phase then proceeded using species transport. Furthermore, the monitoring point's simulation is identical to the experimental data monitoring probe, which is used to inspect the mass fraction at each point. After all, this simulation contains three processes: pre-processing, solving, and post-processing. as a result, the propeller's higher rotational speed makes the mixing time shorter in the CFD method, which has a good agreement with the experimental method. Moreover, this study also examines the impact of the grid's type and the geometric size for the mixing process in the side-entry mixer tank.

System Matched 3D Radial Impeller Design With Variable Inlet Angle Distributions

2012 ◽  
Author(s):  
Matthias Semel ◽  
Henrik Smith ◽  
Philipp Epple ◽  
Oliver Litfin ◽  
Antonio Delgado ◽  
...  
Keyword(s):  
Rotational Speed ◽  
High Efficiency ◽  
Low Flow ◽  
Hydraulic Efficiency ◽  
Linear Variation ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Flow Rates ◽  
Lower Flow ◽  
Inlet Angle

In vacuum cleaners radial impellers with high rotational speed are very often used. A high rotational speed is connected with a best efficiency point of the radial impeller at a high flow rate. This is contrary to the working point of the whole system. Thus there is need for a radial impeller designs having a high efficiency at low flow rates under the restriction of a high rotational speed. One important parameter connected to the hydraulic efficiency characteristics of the radial impeller is the blade inflow angle β1. In order to shift the best efficiency point towards lower flow rates radial impellers with double curved blades and a linear β1 distribution were designed and CFD simulations were done in order to investigate the effect of this approach. A linear variation of the inflow angle β1 enables the designer to shift the efficiency characteristics of the impeller towards lower flow rates with a gain in hydraulic efficiency and pressure increase.

Modeling and Characterization of Micromachined Bi-Directional Electro-Thermal Vibromotors

2003 ◽  
Author(s):  
Wen-Pin Shih ◽  
Minfan Pai ◽  
Yu-Yun Lin ◽  
Chung-Yuen Hui ◽  
Norman C. Tien
Keyword(s):  
Periodic Solution ◽  
Thermal Actuator ◽  
Impact Model ◽  
Multiple Impacts ◽  
Preliminary Results ◽  
The Impact ◽  
Theory And Experiments ◽  
Impact Head ◽  
Good Agreement

The motion of a micromachined bi-directional electrothermal vibromotor (BETV) is analyzed using an impact model which takes into account of friction and contact, as well as the compliance of the slider and the impact head. This model is shown to address several important issues on the reliable usage of BETV. These include (a) how to achieve the push or pull mode (b) avoiding multiple impacts in one actuation cycle (c) the existence of periodic solution with the same period as the thermal actuator. To test our theory, we fabricated and conducted experiments on several BETV with different geometries. Preliminary results showed good agreement between theory and experiments.

Characterization of Turbulent Flow and Pressure Fluctuations Over a Hydrophone by LES

2015 ◽  
Author(s):  
Aidan Bharath ◽  
Dominic Groulx ◽  
Sean Campbell
Keyword(s):  
Turbulent Flow ◽  
Acoustic Noise ◽  
Pressure Fluctuations ◽  
Noise Generation ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Large Eddy ◽  
Pseudo Noise ◽  
The Impact

This paper presents a numerical CFD study of the turbulent flow at up to 4 m/s of water around an underwater hydrophone from the company Ocean Sonics. At such high flow rates in tidal environments, pseudo-noise, coming from turbulence induced pressure fluctuations around the hydrophone, contaminate the acoustic noise reading obtained with the device. Through the use of fine scale large eddy simulations (LES) in ANSYS Fluent, this study shows the impact of increasing flow velocities on the generated turbulence and vorticity, as well as identifying regions in the flow, and geometric aspects of the device, that are playing the larger role in pseudo-noise generation.

scholarly journals Effects of replacing the nasal cavity with a simple pipe like structure in CFD simulations of the airflow within the upper airways of OSA patients with patient individual flow rates

2017 ◽  
Vol 3 (2) ◽  
pp. 795-798
Author(s):  
Christina Hagen ◽  
Pragathi Gurumurthy ◽  
Thorsten M. Buzug
Keyword(s):  
Nasal Cavity ◽  
Upper Airways ◽  
Cfd Simulations ◽  
Flow Rates ◽  
Computational Costs ◽  
Pressure Distributions ◽  
Abnormal Pressure ◽  
Reconstruction Effort ◽  
Simulated Flow ◽  
Good Agreement

AbstractOSA is characterized by repetitive collapses of the upper airways during sleep. Computational fluid dynamics can be used to investigate the abnormal pressure distribution in the patient’s airways. The computational costs and model reconstruction effort can be reduced by focusing the simulations on the pharynx and replacing the nasal cavity by a simple pipe structure. In this work, the effects of the mentioned replacement on the simulated flow are evaluated. Airflow simulations using the k-ω turbulence model are performed in the anatomically correct airway of a patient having a high difference in the inspiratory volume flow rates of both nostrils, as well as in a model with replaced nasal cavity by a simple pipe structure. The simulated pressure distributions of both models are in very good agreement indicating the acceptability of replacing the nasal cavity by simple pipe structures in in-silico airflow analyses of OSA patients.

scholarly journals CFD and Experimental Characterization of a Bioreactor: Analysis via Power Curve, Flow Patterns and k L a

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 878
Author(s):  
Luis A. Ramírez ◽  
Edwar L. Pérez ◽  
Cesar García Díaz ◽  
Dumar Andrés Camacho Luengas ◽  
Nicolas Ratkovich ◽  
...  
Keyword(s):  
Lower Energy ◽  
Scaling Up ◽  
Airflow Rate ◽  
Biological Processes ◽  
Experimental Characterization ◽  
Cfd Simulations ◽  
Transfer Rates ◽  
Curve Flow ◽  
The Impact

Mixing operations in biological processes is of utmost importance due to its effect on scaling-up and heat and mass transfer. This paper presents the characterization of a bench-top bioreactor with different impeller configurations, agitation and oxygen transfer rates, using CFD simulations and experimental procedures. Here, it is demonstrated that factors such as the type of impeller and the flow regime can drastically vary the operation as in the preparation of cultures. It was observed that the bioreactor equipped with a Rushton generates a k L a of 0.0056 s−1 for an agitation velocity and airflow rate of 250 RPM and 5 L/min, respectively. It is suitable result for the dissolved oxygen (DO) but requires a considerable amount of power consumption. It is here where the importance of the agitator’s diameter can be observed, since, in the case of the two propeller types studied, lower energy consumption can be achieved with a smaller diameter, as well as a much smaller shear cup 2.376 against 0.723 s−1 by decreasing by 4 cm the standard diameter of an agitated tank (10 cm). Finally, the k L a values obtained for the different configurations are compared with the maximum shear rate values of different cell cultures to highlight the impact of this study and its applicability to different industries that use agitation processes for cell growth.

scholarly journals Characterization of Functionally Graded Timoshenko Beams with Variable Rotational Speed

2019 ◽  
Vol 8 (4) ◽  
pp. 5926-5931
Keyword(s):  
Rotational Speed ◽  
Angular Speed ◽  
Functionally Graded ◽  
Timoshenko Beams ◽  
The Finite Element Method ◽  
Axial Loads ◽  
Fgm Beam ◽  
The Stability ◽  
Good Agreement

This paper investigates the free vibration characteristics and stability of a functionally graded Timoshenko beam spinning with variable angular speed. Material properties of the beam are assumed to be varied continuously along the thickness of the beam according to a power law and exponential law. The results show that increasing beam rotational speed increases fundamental mode frequency and the beam becomes more and more stable at higher speeds. This paper reports the dynamic behaviour of a rotating FGM beam subjected to axial periodic forces using the finite element method. The numerical results show good agreement with the reported beams models. Effects of static and time dependent components of axial loads on the stability of the FGM beam have been studied.

Aerodynamic and Thermo-Chemical Assessment of a Post-Catalyst Burnout Zone Liner

2003 ◽  
Author(s):  
Sarento G. Nickolas ◽  
Suresh R. Vilayanur ◽  
Mark J. Spencer ◽  
Anthony Watts ◽  
Andrew Hamer
Keyword(s):  
Boundary Conditions ◽  
Thermal Design ◽  
Heat Transfer Analysis ◽  
Cfd Simulations ◽  
Seal Design ◽  
Burn Out ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
The City

A Kawasaki Heavy Industries M1A-13X engine equipped with a Xonon® Cool Combustion System was used to assess the “effectiveness” of a post-catalyst burnout zone liner. The engine is currently installed at the City of Santa Clara’s Silicon Valley Power municipal electrical generating stations and connected to the grid. Post-catalyst burnout zone liner aero-thermal design and inlet boundary conditions play an important role in achieving low CO emissions. In this particular study, these parameters have been evaluated to minimize CO emissions (by maximizing CO burnout). An aero thermal analysis was conducted using Computational Fluid Dynamics (CFD) simulations of the liner for two distinct engine configurations. The analysis includes characterization of the inlet boundary conditions, heat transfer analysis, ignition delay time, liner residence time and the aerodynamic flow field. In addition, engine tests were used to measure and evaluate the impact of design features on CO emissions. Tests were conducted using new seal design and catalyst liner interface configurations. Results from both of these investigations were then used to determine the “effectiveness” of the liner. The CFD analysis and engine test data identified potential regions of improvement to maximize CO burnout in the Burn out Zone (BOZ) liner. These improvements included changing the inlet boundary conditions as well as modifying the BOZ geometry. Ultimately, a solution scheme was selected and changes were made to the catalyst seal design as well as the catalyst to container interface. Upon implementation, these changes yielded an improved effectiveness and extended the operating range of the engine by minimizing CO emissions.

CFD Simulations and Experimental Study of Two-Phase Flow in Sand Coremaking Process

2002 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Experimental Study ◽  
Numerical Simulations ◽  
Electronic System ◽  
Cfd Simulations ◽  
Two Phase ◽  
Flow Rates ◽  
Contour Maps ◽  
Pressure Distributions ◽  
Computer Controlled ◽  
Good Agreement

The results of an experimental study and 3D numerical simulations of resin bonded sand/air flow in a square corebox with an H-shape insertion and passage between upper and lower pockets of the pattern are presented. A computer controlled electronic system was designed and built to measure pressures and flow rates inside the corebox during mold filling, gassing and purging cycles of Phenolic Urethane Amine (PUA) process. Contour maps of the pressure distributions inside the corebox were created based on barometric measurements. A good agreement between experimental results and numerical simulations was found.

scholarly journals Development of a Control-Oriented Model of the Vertical Motions of a Fast Ferry

2004 ◽  
Vol 48 (03) ◽  
pp. 218-230
Author(s):  
Segundo Esteban ◽  
Jose M. Giron-Sierra ◽  
Bonifacio de Andres-Toro ◽  
Jesus M. de la Cruz
Keyword(s):  
Computer Aided Design ◽  
High Speed ◽  
Research Study ◽  
Control Strategies ◽  
Simulated Data ◽  
Irregular Waves ◽  
Towing Tank ◽  
Aided Design ◽  
The Impact ◽  
Good Agreement

As a main part of a research study on the control of active flaps and a T-foil of a high-speed ferry, a control-oriented model of vertical motions of the ship has been developed. The objective of the control is to improve comfort, decreasing the impact of heave and pitch motions. We have experimental data from a towing tank institution and simulations with PRECAL. The model is based on a decomposition of the physic phenomena into two main aspects: the coupling of the ship with distance between waves and the dynamics of a semisubmerged mass. The model can be handled with MATLAB-SIMULINK, which is useful for studying control strategies. The model shows good agreement (model validation) with the experimental and simulated data for regular and irregular waves. The article shows a methodology, based on MATLAB tools, for obtaining control-oriented models from computer-aided design (CAD)–based programs. That means that the control-oriented model can be derived from the ship design, even before the ship is built.

Sign in / Sign up

Export Citation Format

Share Document