Flow Analysis and Assessment of Loss Models in the Symmetric Volute of a Turbo-Blower

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Semi Kim ◽  
Junyoung Park ◽  
Bumseok Choi ◽  
Jehyun Baek
Keyword(s):  
Cfd Simulation ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Cfd Simulations ◽  
Turbo Blower ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd ◽  
Loss Coefficients ◽  
Simulated Flow

The objectives of the present study were to investigate the flow structure and assess the accuracy of loss correlations in the symmetric volute of a turbo-blower using 3D steady flow analysis methods. To accurately model the flow field in the volute, an impeller with a single blade, a diffuser with 13 vanes, and a volute were used as the calculation domains for the computational fluid dynamics (CFD) simulations. Numerical results were validated by comparison with experimental results for the performance of a turbo-blower operated under three operating conditions: high (0.38 kg/s), normal (0.3 kg/s), and low (0.23 kg/s) mass flow rates. The accuracy of the loss correlation sets reported in four previous studies was compared with the CFD simulation predictions. These comparisons showed that the correlation sets did not accurately represent the total pressure loss in the symmetric volute of a turbo-blower, and a modified correlation set that included adjustments for the loss coefficients was proposed. Detailed investigations of the simulated flow fields were compared to understand the flow characteristics in the volute under the designed operating conditions.

scholarly journals Design and Flow Analysis of an Adjustable Check Valve by Means of CFD Method

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2237
Author(s):  
Grzegorz Filo ◽  
Edward Lisowski ◽  
Janusz Rajda
Keyword(s):  
Cfd Simulation ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Check Valve ◽  
The Body ◽  
Cfd Simulations ◽  
Valve Body ◽  
Main Research ◽  
Flow Channels ◽  
Simulation Results

The article presents results of research on an adjustable check valve. In particular, the article deals with improvement of flow characteristics and reduction in pressure losses of an existing valve design. The subject of the research was the valve body in the form of a steel block intended for mounting a typical cartridge valve insert. Two variants of the valve body were analysed: a standard one, which is currently in production, and the proposed new solution, in which the geometry was modified based on the results of CFD simulations. The main research task was to properly shape and arrange holes and flow channels inside the body, between the cartridge valve and the connecting plate. Using CFD analyses, a solution for minimising the flow resistance was sought and then the method of modifying flow channels geometry was developed. The CFD simulation results showed a significant reduction in pressure loss, up to 40%. The obtained simulation results were verified on a test bench using a prototype of the proposed valve block. A high degree of consistency in the results of CFD simulations and laboratory experiments was achieved. The relative difference between simulation and experimental results in the entire considered range of the flow rate did not exceed 6.0%.

CFD simulation of empty fuel tanks separation from a trainer jet

2020 ◽  
Vol 92 (10) ◽  
pp. 1459-1468
Author(s):  
Aleksander Olejnik ◽  
Adam Dziubiński ◽  
Łukasz Kiszkowiak
Keyword(s):  
Cfd Simulation ◽  
Body Movement ◽  
Cfd Simulations ◽  
Content Type ◽  
Sequential Release ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
External Forces ◽  
Additional Value ◽  
Control Surfaces

Purpose This study aims to create 6-degree of freedom (SDOF) for computational fluid dynamics (CFD) simulations of body movement, and to validate using the experimental data for empty tank separation from I-22 Iryda jet trainer. The procedure has an ability to be modified or extended, to simulate, for example, a sequential release from the joints. Design/methodology/approach A set of CFD simulations are calculated. Both the SDOF procedure and the CFD simulation settings are validated using the wind tunnel data available for the aircraft. Findings The simulation using designed procedure gives predictable results, but offers availability to be modified to represent external forces, i.e. from body interaction or control system without necessity to model the control surfaces. Practical implications The procedure could be used to model the separation of external stores and design the deployment of anti-radar chaff, flares or ejection seats. Originality/value The work presents original work, caused by insufficient abilities of original SDOF procedure in ANSYS code. Additional value is the ability of the procedure to be easily modified.

scholarly journals Thermal management of machine compartment in a built-in refrigerator

2018 ◽  
Vol 240 ◽  
pp. 05005
Author(s):  
Milind Devle ◽  
Ankur Garg ◽  
Darci Cavali
Keyword(s):  
Heat Exchange ◽  
Cfd Simulation ◽  
Heat Extraction ◽  
Free Standing ◽  
Cfd Simulations ◽  
Performance Effectiveness ◽  
Hot Air ◽  
Computational Fluid Dynamics Cfd ◽  
Major Factors ◽  
Side Gap

In general a multi-door refrigerator machine compartment comprises of fan, condenser, compressor, control box, drain tray, and drain tubes. The performance of machine compartment depends upon the efficiency of heat extraction or heat exchange from heat generating components such as condenser and compressor. The efficiency of heat exchange can be improved by addressing two major factors, namely (1) Air bypass and (2) Hot air recirculation. The hot air recirculation in the machine compartment for builtin multi-door refrigerator configuration is the focus of this study. The results from Computational Fluid Dynamics (CFD) simulations show that efficiency of heat exchange for built-in application is lower than that for free-standing configuration. Recirculation of hot air and reduction in airflow are the two major factors which contribute towards the variation in machine compartment performance. The CFD simulations were coupled with Partial Factorial Design of Experiment (DoE) approach to systematically investigate the effect of variables such as (a) side gap and top gap between kitchen cabinetry and the refrigerator, (b) the baffle/flap (i.e. back and bottom of machine compartment) on the performance effectiveness of machine compartment. The results of the simulation provided critical design improvement directions resulting in performance improvement. Furthermore, the CFD simulation results were also compared to test data and the results compared favourably.

CFD Simulations of the Cold Neutron Source at the OPAL Reactor

2020 ◽  
Author(s):  
James L Spedding ◽  
Mark Ho ◽  
Weijian Lu
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Operating Conditions ◽  
Convergence Time ◽  
Cfd Model ◽  
Cfd Simulations ◽  
Cold Neutron Source ◽  
Order Of Magnitude ◽  
Computational Fluid Dynamics Cfd ◽  
Polyhedral Mesh

Abstract The Open Pool Australian Light-water (OPAL) reactor Cold Neutron Source (CNS) is a 20 L liquid deuterium thermosiphon system which has performed consistently but will require replacement in the future. The CNS deuterium exploits neutronic heating to passively drive the thermosiphon loop and is cryogenically cooled by forced convective helium flow via a heat exchanger. In this study, a detailed computational fluid dynamics (CFD) model of the complete thermosiphon system was developed for simulation. Unlike previous studies, the simulation employed a novel polyhedral mesh technique. Results demonstrated that the polyhedral technique reduced simulation computational requirements and convergence time by an order of magnitude while predicting thermosiphon performance to within 1% accuracy when compared with prototype experiments. The simulation model was extrapolated to OPAL operating conditions and confirmed the versatility of the CFD model as an engineering design and preventative maintenance tool. Finally, simulations were performed on a proposed second-generation CNS design that increases the CNS moderator deuterium volume by 5 L, and results confirmed that the geometry maintains the thermosiphon deuterium in the liquid state and satisfies the CNS design criteria.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

CFD Simulation of Semi-Submersible Floating Offshore Wind Turbine Under Pitch Decay Motion

2019 ◽  
Author(s):  
Yu Wang ◽  
Hamn-Ching Chen ◽  
Guilherme Vaz ◽  
Simon Burmester
Keyword(s):  
Wind Turbine ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Hydrodynamic Pressure ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Natural Period ◽  
Hydrodynamic Damping ◽  
Computational Data ◽  
Computational Fluid Dynamics Cfd

Abstract The application of a computational fluid dynamics (CFD) code to simulate the response of a semi-submersible floating wind turbine under pitch decay motion was investigated in this study. Estimation of the natural period, the hydrodynamic damping and the flow characteristics were the main focus of this study. An extensive verification study of the simulation results was conducted to improve the confidence and reliability of the numerical simulation by the estimation of the numerical errors and uncertainties. The time series of pitch motion was plotted against model test data. In addition, the pitch period and hydrodynamic damping were calculated and compared to experimental data. Detailed flow characteristics as vorticity field and hydrodynamic pressure field on the floater surface were illustrated after post processing of the computational data. The results of the flow characteristics suggest that the heave damping plates were a major contributor to the hydrodynamic damping of this floater in pitch decay.

scholarly journals Using CFD Simulations to Guide the Development of a New Spray Dryer Design

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 932
Author(s):  
Timothy A. G. Langrish ◽  
James Harrington ◽  
Xing Huang ◽  
Chao Zhong
Keyword(s):  
Deposition Process ◽  
Operating Conditions ◽  
Feed Concentration ◽  
Cfd Simulations ◽  
Physical Experiments ◽  
Solids Concentration ◽  
Computational Fluid Dynamics Cfd ◽  
Higher Temperature ◽  
Drying System ◽  
Drying Chamber

A new spray-drying system has been designed to overcome the limitations caused by existing designs. A key feature of the approach has been the systematic use of Computational Fluid Dynamics (CFD) to guide innovation in the design process. An example of an innovation is the development of a box-shaped transitional feature between the bottom of the main drying chamber and the entrance to the secondary chamber. In physical experiments, the box design performed better in all three representative operating conditions, including the current conditions, a higher feed solids concentration (30% solids rather than 8.8%), and a higher inlet drying temperature (230 °C rather than 170 °C). The current conditions showed a 3% increase in yield (solids recovery) while the 30% feed condition improved the yield by 7.5%, and the higher temperature test increased the yield by 13.5%. Statistical analysis showed that there were significant reductions in the wall flux at the high solids feed concentration. The observed deposition in the box was primarily from the predicted particle impacts by an inertial deposition process on the base of the box, which underwent little degradation due to lower temperatures. There is therefore evidence that the box design is a better design alternative under all operating conditions compared with other traditional designs.

scholarly journals Performance Optimization of Ejector using Computation Fluid Dynamics

2020 ◽  
Vol 8 (5) ◽  
pp. 2905-2910
Keyword(s):  
Fluid Dynamics ◽  
Performance Optimization ◽  
Cfd Simulation ◽  
Experimental Testing ◽  
High Reliability ◽  
Fluid Velocity ◽  
Pressure Ratio ◽  
Operating Cost ◽  
Flow Characteristics ◽  
Operating Conditions

Ejector is a device used for carry low pressure fluids with no mechanical force, high pressure flow. This contains the main nozzle, chamber for suction, chamber for mixing and diffu ser.It is used in vaccum pumps, condensers, steam refrigeration, Because of its simple structure, gas mixing, pneumatic transport (no moving parts) and reliable operation. It is also used in pumps for lifting slurries and waste material containing solids from tanks and sumps. Due to their simplicity and high reliability, however, jet ejectors are widely used in industries with low efficie ncy. The project's goal is to optimize the efficiency of jet ejectors for each operating condition.Consequently, the primary fluid consumption and operating cost is minimized. A commercial computational fluid dynamics tool would be used to analyse the flow characteristics inside the ejector geometry. The results of the CFD simulation could be used to understand the effect of fluid velocity and pressure ratio on the ejector performance. The analysis would also be carried out by varying the primary and secondary nozzle dimensions. Performance of ejectors under various operating conditions is generally obtained through an experimental testing of prototype or scaled ejectors. The availability of performance parameters for such ejectors is limited, and experimental testing can be cost prohibitive.

scholarly journals The Efficient Application of an Impulse Source Wavemaker to CFD Simulations

2019 ◽  
Author(s):  
Pál Schmitt ◽  
Christian Windt ◽  
Josh Davidson ◽  
John V. Ringwood ◽  
Trevor Whittaker
Keyword(s):  
Shallow Water ◽  
Source Function ◽  
Cfd Simulation ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wide Range ◽  
Rans Models ◽  
Hydrodynamic Processes ◽  
Computational Fluid Dynamics Cfd ◽  
Shallow Water Models

Computational Fluid Dynamics (CFD) simulations, based on Reynolds Averaged Navier Stokes (RANS) models, are a useful tool for a wide range of coastal and offshore applications, providing a high fidelity representation of the underlying hydrodynamic processes. Generating input waves in the CFD simulation is performed by a numerical wavemaker (NWM), with a variety of different NWM methods existing for this task. While NWMs, based on impulse source methods, have been widely applied for wave generation in depth averaged, shallow water models, they have not seen the same level of adoption in the more general RANS based CFD simulations, due to difficulties in relating the required impulse source function to the resulting free surface elevation for non-shallow water cases. This paper presents an implementation of an impulse source wavemaker, which is able to self-calibrate the impulse source function to produce a desired wave series in deep or shallow water at a specific point in time and space. Example applications are presented, for a numerical wave tank (NWT), based on the opensource CFD software OpenFOAM, for wave packets in deep and shallow water, highlighting the correct calibration of phase and amplitude. Also, the suitability for cases requiring very low reflection from NWT boundaries is demonstrated. Possible issues in the use of the method are discussed and guidance for good application is given.

CFD Simulation of Slug Dissipation in an Enlarged Impacting Tee

2019 ◽  
Author(s):  
Mobina Mohammadikharkeshi ◽  
Mazdak Parsi ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Experimental Data ◽  
Void Fraction ◽  
Cfd Simulation ◽  
Petroleum Industry ◽  
Production Operation ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Transient Model ◽  
Diameter Pipe ◽  
Computational Fluid Dynamics Cfd

Abstract Slug flow, which commonly occurs in the petroleum industry, is not always a desired flow pattern due to production operation problems it may cause in pipelines and processing facilities. To mitigate these problems, flow conditioning devices such as multiphase flow manifolds and slug catchers are used, where dissipation of slugs occurs in downward flow or in larger diameter pipe sections. Tee-junctions are important parts of these flow conditioning devices. In this work, Computational Fluid Dynamics (CFD) simulations are conducted using ANSYS/FLUENT 17.2 to investigate slug dissipation in an Enlarged Impacting Tee-Junction (EIT). An Eulerian–Eulerian MultiFluid VOF transient model in conjunction with the standard k-ε turbulent model is used to simulate slug dissipation in an EIT geometry. The EIT consists of a 0.05 m ID 10 m long inlet, which is connected to the center of a 0.074 m ID 5.5 m long section that forms the EIT branches. Moreover, experimental data are acquired on slug dissipation lengths in a horizontal EIT with a similar geometry as in the CFD simulations. The CFD results include the mean void fraction and cross-sectionally averaged void fraction time series in the EIT for different gas and liquid velocities. These results provide the inlet slug length and dissipation length in the EIT branches. The CFD results are evaluated against the experimental data demonstrating that the slug dissipation occurring in EIT branches can be predicted by simulation.

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