Energy Efficiency of an Axial Fan for Various Casing Configurations

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Alain Guedel ◽  
Mirela Robitu ◽  
Vivian Chaulet
Keyword(s):  
Energy Efficiency ◽  
Axial Fan ◽  
Cfd Simulations ◽  
Fan Performance ◽  
Commercial Code ◽  
Performance Curves ◽  
Commission Regulation ◽  
Target Energy ◽  
Parametric Studies ◽  
Computational Fluid Dynamics Cfd

The objective of this paper is to compare the measured and predicted performances of a tubeaxial fan for several casing configurations that are commonly proposed by fan manufacturers to their clients. This work is motivated by the European Commission Regulation 327/2011, which will impose target energy efficiency for fans driven by electric motors beginning 1 January 2013. The prediction is made with the computational fluid dynamics (CFD) commercial code STAR-CCM+. The agreement between the experimental and numerical results on fan performance curves is very satisfactory, which confirms that CFD simulations may advantageously replace testing in parametric studies since they predict the quantitative differences of aerodynamic performance observed experimentally between the different casing configurations quite well. Numerical simulations may, therefore, help manufacturers to improve the geometry of their fans in order to fulfill the requirements of the regulation.

A Systematical Study of the Influence of Blade Number on the Performance of a Side Channel Pump

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Annika Fleder ◽  
Martin Böhle
Keyword(s):  
Experimental Studies ◽  
Numerical Results ◽  
Channel Height ◽  
Side Channel ◽  
Outer Diameter ◽  
Cfd Simulations ◽  
Blade Number ◽  
Performance Curves ◽  
Flow Phenomena ◽  
Computational Fluid Dynamics Cfd

For side channel machines, distinction is made between side channel pumps and peripheral pumps. The blade number of side channel machines has a large influence on the performance of the pump. This is known from several experimental studies. For industrial side channel pumps, the blade number is between 20 and 26, whereas for industrial peripheral pumps, the blade number is much larger (between 36 and 90). In this paper, the influence of the blade number on the performance and the inner flow phenomena of different pumps will be investigated experimentally and numerically. The inner flow of the pump is examined in detail by computational fluid dynamics (CFD) simulations. Flow angles and velocities of the circulation flow between side channel and impeller are considered for different blade numbers. To explain the influences of the blade number, numerical results and theoretical formulas are combined. The experiments are carried out for two different modular side channel pump units, which differ in the side channel height h, the outer impeller diameter da, and the length of the blades l. So, the influence of the blade number can be studied in the context of other parameters like, for example, the relation between blade length and outer diameter of the pump. The obtained numerical results are compared with experimental data. Effects of the blade number on the performance curves of the pumps are shown by experimental and numerical results.

Ablation and Aero-thermodynamic Studies on Thermal Protection Systems of Sharp-Nosed Re-entry Vehicles

2006 ◽  
Vol 129 (7) ◽  
pp. 912-916 ◽  
Author(s):  
S. Rameche Candane ◽  
C. Balaji ◽  
S. P. Venkateshan
Keyword(s):  
Thermodynamic Analysis ◽  
Thermal Protection ◽  
Ablation Rate ◽  
Heat Fluxes ◽  
Zirconium Boride ◽  
Cfd Simulations ◽  
Flow And Heat Transfer ◽  
Commercial Code ◽  
Computational Fluid Dynamics Cfd ◽  
Viscous Compressible Flow

A quasi-one-dimensional ablation analysis for a sharp-nosed, reusable, re-entry vehicle that could possibly be used in an unmanned space program, has been carried out by using an in-house code. The code is based on the boundary immobilization technique and the solution has been obtained using the tri-diagonal matrix algorithm (TDMA). The heat fluxes on the spherical nose cap that are used to determine the ablation rate of a thermal coating applied over the surface of the vehicle are obtained by performing a steady state aero-thermodynamic analysis. The aero-thermodynamic analysis for the viscous, compressible flow under consideration is carried out by using FLUENT 6.2. The computational fluid dynamics (CFD) simulations are performed at three locations on the trajectory that the vehicle follows, on re-entry. These simulations yield the temperature and heat flux distributions along the surface of the vehicle and the latter are given as input to the ablation code. The shell material of the vehicle is assumed to be zirconium boride (ZrB2). The code is validated with benchmark cases and the flow and heat transfer characteristics are also discussed. In brief, the present work presents a methodology for coupling an ablation code with CFD simulations from a commercial code, to study the effect of change of the nose region on the ablation process.

A Single-Stage Centripetal Pump—Design Features and an Investigation of the Operating Characteristics

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Mihael Sekavčnik ◽  
Tine Gantar ◽  
Mitja Mori
Keyword(s):  
Single Stage ◽  
Flow Conditions ◽  
Operating Characteristics ◽  
Cfd Simulations ◽  
Pump Design ◽  
Flow Channels ◽  
Performance Curves ◽  
Computational Fluid Dynamics Cfd ◽  
Working Media ◽  
Inflow Conditions

In this paper, we present an experimental and numerical investigation of a single-stage centripetal pump (SSCP). This SSCP is designed to operate in the pump regime, while forcing the working media through impeller-stator flow channels in the radial inward direction. The measured performance curves are characterized by a hysteresis, since the throttle-closing performance curves do not correspond to the throttle-opening performance curves throughout the whole operating range. A computational fluid dynamics (CFD) model was developed to establish these throttle-closing and throttle-opening performance curves. The flow conditions obtained with the CFD simulations confirm that the hydraulic behavior of the SSCP is influenced by the partial circumferential stall that occurs in the impeller-stator flow channels. It was shown that the inflow conditions to the impeller-stator assembly considerably influence the flow rate of the stall cessation, the size of the hysteresis, and the head generated during part-load operations.

scholarly journals Numerical Simulation of Internal Loop Reactor for Heavy Oil Slurry Bed Hydroprocessing

2014 ◽  
Vol 7 (1) ◽  
pp. 47-54
Author(s):  
Sun Lanyi ◽  
Wang Jian ◽  
Bai Fei ◽  
Bo Shoushi
Keyword(s):  
Flow Field ◽  
Heavy Oil ◽  
Flow Model ◽  
Scale Up ◽  
Cfd Simulations ◽  
Two Phase ◽  
Loop Reactor ◽  
Internal Loop ◽  
Commercial Code ◽  
Computational Fluid Dynamics Cfd

Computational Fluid Dynamics (CFD) simulations of internal loop reactor for heavy oil slurry bed hydroprocessing have been done in commercial code Fluent 6.3 using Euler two-phase flow model and standard k-ε turbulence model. The effects of the physical properties on the flow field in the reactor are investigated. The results show that the gas density has little effect but the liquid viscosity has a significant effect on flow field and gas hold-up. An analysis of the effect of reactor structures and scale-up on the flow field and gas hold-up are also provided, and optimal structure is obtained through simulations. The conclusions obtained in this paper have great significance for the slurry bed hydrocracking process.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

Fan Performance Scaling With Inlet Distortions

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
J. J. Defoe ◽  
M. Etemadi ◽  
D. K. Hall
Keyword(s):  
Design Flow ◽  
Flow Coefficient ◽  
Axial Fan ◽  
Fan Performance ◽  
Physical Mechanisms ◽  
Viscous Losses ◽  
Performance Scaling ◽  
Large Distortion ◽  
Stator Blade ◽  
Primary Focus

Applications such as boundary-layer-ingesting (BLI) fans and compressors in turboprop engines require continuous operation with distorted inflow. A low-speed axial fan with incompressible flow is studied in this paper. The objectives are to (1) identify the physical mechanisms which govern the fan response to inflow distortions and (2) determine how fan performance scales as the type and severity of inlet distortion varies at the design flow coefficient. A distributed source term approach to modeling the rotor and stator blade rows is used in numerical simulations in this paper. The model does not include viscous losses so that changes in diffusion factor are the primary focus. Distortions in stagnation pressure and temperature as well as swirl are considered. The key findings are that unless sharp pitchwise gradients in the diffusion response, strong radial flows, or very large distortion magnitudes are present, the response of the blade rows for strong distortions can be predicted by scaling up the response to a weaker distortion. In addition, the response to distortions which are composed of nonuniformities in several inlet quantities can be predicted by summing up the responses to the constituent distortions.

Analysis of Late Phase Severe Accident Phenomena in CANDU Plant

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
D. Dupleac
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Late Phase ◽  
Severe Accident ◽  
Ansys Fluent ◽  
Water Depletion ◽  
Sources Of Uncertainty ◽  
Parametric Studies ◽  
Computational Fluid Dynamics Cfd ◽  
Containment Pressure

The paper overviews the analytical studies performed at Politehnica University of Bucharest on the analysis of late phase severe accident phenomena in a Canada Deuterium Uranium (CANDU) plant. The calculations start from a dry debris bed at the bottom of calandria vessel. Both SCDAPSIM/RELAP code and ansys-fluent computational fluid dynamics (CFD) code are used. Parametric studies are performed in order to quantify the effect of several identified sources of uncertainty on calandria vessel failure: metallic fraction of zirconium inside the debris, containment pressure, timing of water depletion inside calandria vessel, steam circulation in calandria vessel above debris bed, debris temperature at moment of water depletion inside calandria vessel, calandria vault nodalization, and the gap heat transfer coefficient.

scholarly journals Investigations of Inducers Operating With High Rotational Speed

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Björn Gwiasda ◽  
Matthias Mohr ◽  
Martin Böhle
Keyword(s):  
Rotational Speed ◽  
Test Bench ◽  
Pressure Rise ◽  
Working Fluid ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Performance Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Performance

Suction performance, pressure rise, and efficiency for four different inducers are examined with computational fluid dynamics (CFD) simulations and experiments performed with 18,000 rpm and 24,000 rpm. The studies originate from a research project that includes the construction of a new test bench in order to judge the design of the different inducers. This test bench allows to conduct experiments with a rotational speed of up to 40,000 rpm and high pressure ranges from 0.1 bar to 40 bar with water as working fluid. Experimental results are used to evaluate the accuracy of the simulations and to gain a better understanding of the design parameter. The influence of increasing the rotating speed from 18,000 rpm to 24,000 rpm on the performance is also shown.

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