scholarly journals CFD Simulation Study on the Performance of a Modified Ram Air Turbine (RAT) for Power Generation in Aircrafts

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 391
Author(s):  
Magedi Moh M. Saad ◽  
Sofian Mohd ◽  
Mohd Fadhli Zulkafli ◽  
Nor Afzanizam Samiran ◽  
Djamal Hissein Didane
Keyword(s):  
Fossil Fuels ◽  
Cfd Simulation ◽  
Turbulence Modeling ◽  
3D Models ◽  
Navier Stokes ◽  
Axial Distance ◽  
Navier Stokes Equation ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Air Turbine

The present paper aims to study the possibility of dispensing an auxiliary power unit (APU) in an aircraft powered by fossil fuels to reduce air pollution. It particularly seeks to evaluate the amount of power generated by the ram air turbine (RAT) using the novel counter-rotating technique while characterizing its optimum axial distance. The ram air turbine (RAT), which is already equipped in aircrafts, was enhanced to generate the amount of energy produced by the APU. The approach was implemented by a CRRAT system. Six airfoil profiles were tested based on 2D models and the best airfoil was chosen for implantation on the RAT and CRRAT systems. The performance of the conventional single-rotor RAT and CRRAT were analyzed using FLUENT software based on 3D models. The adopted numerical scheme was the Navier–Stokes equation with k–ω SST turbulence modeling. The dynamic mesh and user-defined function (UDF) were used to revolve the rotor turbine via wind. The results indicated that the FX63-137 airfoil profile showed a higher performance in terms of the lift-to-drag ratio compared to the other airfoils. The optimum axial distance between the two rotors was 0.087 m of the rotor diameter and the efficiency of the new CRRAT increased to almost 45% compared to the single-rotor RAT.

A Verification and Validation Study of CFD Simulation of Wind-Induced Ventilation on Building with Single-Sided Opening

2014 ◽  
Vol 554 ◽  
pp. 696-700 ◽  
Author(s):  
Nur Farhana Mohamad Kasim ◽  
Sheikh Ahmad Zaki ◽  
Mohamed Sukri Mat Ali ◽  
Ahmad Faiz Mohammad ◽  
Azli Abd Razak
Keyword(s):  
Open Source Software ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Previous Experiment ◽  
Experimental Methods ◽  
Verification And Validation ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Computational Fluid Dynamics Cfd ◽  
Model Approach

Wind-induced ventilation is widely acknowledged as one of the best approaches for inducing natural ventilation. Computational fluid dynamics (CFD) technique is gaining popularity among researchers as an alternative for experimental methods to investigate the behavior of wind-driven ventilation in building. In this present paper, Reynolds averaged Navier-Stokes equation (RANS) k-ε model approach is considered to simulate the airflow on a simplified cubic building with an opening on a single façade. Preliminary simulation using models from previous experiment indicates the reliability of OpenFOAM, the open source software that will be used in this study. The results obtained in this study will better define options for our future study which aims to explore how different buildings arrays modify the airflow inside and around a naturally ventilated building.

scholarly journals Method of coordinating air starter and auxiliary power unit joint operation

2020 ◽  
pp. 5-13
Author(s):  
Grigory Popov ◽  
◽  
Vasily Zubanov ◽  
Valeriy Matveev ◽  
Oleg Baturin ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Gas Turbine Engine ◽  
Working Process ◽  
Joint Operation ◽  
Turbine Engine ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Start Up ◽  
Air Turbine

The presented work provides a detailed description of the method developed by the authors for coordinating the working process of the main elements of the starting system for a modern gas turbine engine for a civil aviation aircraft: an auxiliary power unit (APU) and an air turbine – starter. This technique was developed in the course of solving the practical problem of selecting the existing APU and air turbine for a newly created engine. The need to develop this method is due to the lack of recommendations on the coordination of the elements of the starting system in the available literature. The method is based on combining the characteristics of the APU and the turbine, reduced to a single coordinate system. The intersection of the characteristic’s lines corresponding to the same conditions indicates the possibility of joint operation of the specified elements. The lack of intersection indicates the impossibility of joint functioning. The calculation also takes into account losses in the air supply lines to the turbine. The use of the developed method makes it possible to assess the possibility of joint operation of the APU and the air turbine in any operating mode. In addition to checking the possibility of functioning, as a result of the calculation, specific parameters of the working process at the operating point are determined, which are then used as initial data in calculating the elements of the starting system, for example, determining the parameters of the turbine, which in turn allow providing initial information for calculating the starting time or the possibility of functioning of the starting system GTE according to strength and other criteria. The algorithm for calculating the start-up time of the gas turbine engine was also developed by the authors and implemented in the form of an original computer program. Keywords: gas turbine engine start-up, GTE starting system, air turbine, methodology, joint work, auxiliary power unit, power, start-up time, characteristics matching, coordination, operational characteristics, computer program.

Three-Dimensional Flowfields Inside a Transonic Compressor With Swept Blades

1991 ◽  
Vol 113 (2) ◽  
pp. 241-250 ◽  
Author(s):  
C. Hah ◽  
A. J. Wennerstrom
Keyword(s):  
Turbulence Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Tip Clearance Flow ◽  
Transonic Compressor ◽  
Improved Performance

The concept of swept blades for a transonic or supersonic compressor was reconsidered by Wennerstrom in the early 1980s. Several transonic rotors designed with swept blades have shown very good aerodynamic efficiency. The improved performance of the rotor is believed to be due to reduced shock strength near the shroud and better distribution of secondary flows. A three-dimensional flowfield inside a transonic rotor with swept blades is analyzed in detail experimentally and numerically. A Reynolds-averaged Navier–Stokes equation is solved for the flow inside the rotor. The numerical solution is based on a high-order upwinding relaxation scheme, and a two-equation turbulence model with a low Reynolds number modification is used for the turbulence modeling. To predict flows near the shroud properly, the tip-clearance flow also must be properly calculated. The numerical results at three different operating conditions agree well with the available experimental data and reveal various interesting aspects of shock structure inside the rotor.

Wave-in-Deck Load on a Jacket Platform, CFD Calculations Compared With Experiments

2014 ◽  
Author(s):  
Bogdan Iwanowski ◽  
Tone Vestbøstad ◽  
Marc Lefranc
Keyword(s):  
Free Surface ◽  
Industrial Application ◽  
Computational Models ◽  
Cfd Simulation ◽  
Navier Stokes ◽  
Extreme Wave ◽  
Navier Stokes Equation ◽  
Jacket Platform ◽  
Irregular Wave ◽  
Start Up

The paper presents an industrial application of CFD for calculation of Wave-In-Deck load due to an extreme wave. Particular attention is given to flow kinematics initialization that is necessary to start up a CFD simulation. The applied CFD code, ComFLOW, is a Navier-Stokes equation solver with an improved Volume of Fluid (iVOF) method employed to displace and re-construct fluids free surface. For incoming waves high enough for a negative air-gap and therefore with Wave-In-Deck loads, a jacket platform was tested in model basin, for both regular and irregular wave cases. One of goals of these model tests was verification of CFD codes. The experimental and computational models of the structure are exactly the same. In the paper, the measured Wave-In-Deck forces are compared with CFD results.

scholarly journals Three-Dimensional Flowfields Inside a Transonic Compressor With Swept Blades

1990 ◽  
Author(s):  
C. Hah ◽  
A. J. Wennerstrom
Keyword(s):  
Turbulence Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Tip Clearance Flow ◽  
Transonic Compressor ◽  
Improved Performance

The concept of swept blades for a transonic or supersonic compressor was reconsidered by Wennerstrom in the early 1980s. Several transonic rotors designed with swept blades have shown very good aerodynamic efficiency. The improved performance of the rotor is believed to be due to reduced shock strength near the shroud and better distribution of secondary flows. A three-dimensional flowfield inside a transonic rotor with swept blades is analyzed in detail experimentally and numerically. A Reynolds-averaged Navier-Stokes equation is solved for the flow inside the rotor. The numerical solution is based on a high-order upwinding relaxation scheme, and a two-equation turbulence model with a low Reynolds number modification is used for the turbulence modeling. To properly predict flows near the shroud, the tip-clearance flow also must be properly calculated. The numerical results at three different operating conditions agree well with the available experimental data and reveal various interesting aspects of shock structure inside the rotor.

CFD Simulations of Boron Mixing in ESBWR Core Bypass Regions During an Anticipated Transient Without Scram (ATWS) Event

2008 ◽  
Author(s):  
James A. Tallman ◽  
Wayne Marquino ◽  
M. D. Alamgir
Keyword(s):  
Control System ◽  
Design Process ◽  
Cfd Simulation ◽  
Turbulence Modeling ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
The Core ◽  
Time Prediction ◽  
Transport And Mixing ◽  
Borate Solution

CFD was used to simulate boron mixing in the ESBWR core during a limiting ATWS event. During the ESBWR design process, questions were raised regarding the Standby Liquid Control System (SLCS), which adds a sodium penta-borate solution to the core during ATWS events for the purpose of halting reactivity and core shutdown. The questions involved the design prediction of boron transport and mixing in the core bypass spaces, and how that influenced the core shutdown time prediction associated with the SLCS. In response, a CFD simulation was performed to study the mixing of the sodium penta-borate solution in bypass spaces of the ESBWR core. The CFD solution was a transient, Reynolds-Averaged Navier-Stokes (RANS) solution using two-equation turbulence modeling and 25 million computational nodes. Compared with the design predictions, the CFD results showed a much faster transport of boron toward the center of the core and a much greater quantity of boron is ingested into the fuel bundles. These findings demonstrate an adequate level of conservativism in the core shutdown time predictions, and confirm the effectiveness of the ESBWR SLCS system.

A Transient CFD Simulation of the Flow in a Test Rig of an Aeroengine Bearing Chamber

2014 ◽  
Author(s):  
Akinola A. Adeniyi ◽  
Hervé P. Morvan ◽  
Kathy A. Simmons
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Film Formation ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Oil Film ◽  
Sheared Flow ◽  
Fine Mesh ◽  
Computational Overhead ◽  
Formation Pattern

In this paper, we present results for the application of an Eulerian-Lagrangian technique to the transient simulation of an oil film formation on the walls of an aeroengine bearing chamber. The flow of oil in an aeroengine bearing chamber consists of high speed oil droplets interacting with the bearing structures and flowing oil film. The situation in the chamber is highly rotational and consisting of sheared flow of air over oil. The bearing chamber may also be located in the vicinity of the combustion chamber. The oil provides lubrication and cooling of the hot structures. Modelling the flow in the bearing chamber is therefore complex. The Volume of Fluid (VoF) technique offers a potential platform to model droplet-film interaction; however, it requires fine mesh details to capture the flow to the droplet level. Such detailed resolution would not be practical for the complete chamber geometry because of the prohibitively expensive computational overhead requirements. A Lagrangian formulation is therefore proposed to represent the droplets as source terms in the Navier-Stokes equation while the film is represented using VoF. This effectively reduces the need to resolve the droplets explicitly. The predicted film formation pattern compares with experimental results.

CFD Simulation of Heat Transfer in Fluidized Bed Reactor

2014 ◽  
Vol 493 ◽  
pp. 267-272
Author(s):  
I. Nyoman Suprapta Winaya ◽  
I. Made Agus Putrawan ◽  
I. Nyoman Gede Sujana ◽  
Made Sucipta
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Navier Stokes ◽  
Velocity Variation ◽  
Navier Stokes Equation ◽  
Program Language ◽  
The Heat Transfer Coefficient

This study aims to predict heat transfer from a heated bed in a gas fluidized bed using Syamlal-OBrien drag coefficient. Discrete particles model with the Navier-Stokes equation and Eulerian multiphase are used to approach heat transfer simulation. Coefficient of heat transfer which is related to Nusselt Number and volume fraction are calculated using Gunn model which was compiled from C++ program language. The effect of fluidization velocity variation on the heat transfer coefficient comes to the fore, indicating the heat transfer and solid volume fraction at the bed height are very dependent. Contour of solid volume fraction and temperature distribution are also presented.

Effect of Stage Axial Distances on the Aerodynamic Performance of Three-Stage Axial Turbine Using Experimental Measurements and Numerical Simulations

2017 ◽  
Author(s):  
Yang Chen ◽  
Zhuhai Zhong ◽  
Jun Li ◽  
Weijiu Zhou ◽  
Gangyun Zhong ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Velocity Ratio ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Axial Distance ◽  
Axial Turbine ◽  
Air Turbine ◽  
Aerodynamic Parameters

The stage axial distance significantly influences the aerodynamic performance of turbines under some constraints. Experimental measurements and numerical simulations are used to analyze the effect of stage axial distances on the aerodynamic performance of three-stage axial turbine in this work. The aerodynamic performance of three-stage axial turbine with three different stage axial distances is experimentally measured at the air turbine test rig of Dongfang Steam Turbine Co. LTD. Experimental results show that efficiency increases when the stage axial distance decreases for the geometry under study with relative stage distance ranged from 0.14 to 0.35, and the effect of stage axial distance on the optimization velocity ratio here is very limited. In addition, unsteady Reynolds-Averaged Navier-Stokes (RANS) simulations were carried out with nonlinear harmonic method to analyze the detailed flow field of the experimental three-stage axial turbine. The numerical aerodynamic efficiency of three-stage axial turbine is in good agreement with the experimental data. Furthermore, the small stage axial distance is preferred for the higher efficiency. The detailed flow field and aerodynamic parameters of three-stage axial turbine are also illustrated and discussed.

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