Aero Engine Axi-Symmetric Convergent-Constant Area Intake 3D Simulation Using a Panel Method Approach

2005 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Petros Kotsiopoulos ◽  
Vassilios Pachidis
Keyword(s):  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Lattice Method ◽  
Simulation Code ◽  
Lower Lip ◽  
Vortex Lattice Method ◽  
Constant Area ◽  
Computational Fluid Dynamics Cfd ◽  
General Effort

This study has been carried out as a part of a general effort to develope a powerful simulation code, based on the Vortex Lattice Method (VLM), capable of simulating adequately accurate and comparatively fast, internal flow regimes. It utilizes a convergent – (nearly) constant area axi-symmetric intake three dimensional geometry, emerged as a surface of revolution from the CFM56-5B2 lower lip geometry. The study focuses on the three most critical planes, which are the inlet of the intake, the outlet of the diverging section and the outlet of the intake. Moreover, the sensitivity of the simulation on the variation of the Angle Of Attack (AOA) is tested for four different settings equally spaced, ranging from 0 to 20 degrees. The comparison is carried out on both two-dimensional velocity distributions and average values. The VLM simulation code was based on an existing code, which was modified in order to be adapted to the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) boundary conditions.

3D Simulation of a Convergent-Divergent Aero Engine Intake, Using Two Different CFD Methods

2005 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Theodoros Lekas ◽  
Vassilios Pachidis
Keyword(s):  
Vortex Lattice ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Aero Engine ◽  
Flow Effects ◽  
Development And Validation

This study refers to the development and validation of a Three Dimensional (3D) Vortex Lattice Method (VLM) to be used for internal flow case studies and more precisely aero-engine intake simulation. It examines the quantitative and qualitative response of the method to a convergent – divergent intake, produced as a surface of revolution of the CFM56-5B2 upper lip geometry. The study was carried out for three different sections namely: Intake outlet, intake throat and intake inlet. Moreover five different settings of Angle Of Attack (AOA) were considered. The VLM was based on an existing code. It was modified to accommodate internal flow effects and match, as closely as possible, the boundary conditions set by the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulation. In the context of this study, Vortex Lattice-derived average values velocity profiles were compared against RANS CFD results.

A Prescribed-Wake Vortex Lattice Method for Preliminary Design of Co-Axial, Dual-Rotor Wind Turbines

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Aaron Rosenberg ◽  
Anupam Sharma
Keyword(s):  
Wind Turbines ◽  
Vortex Lattice ◽  
Navier Stokes ◽  
Wake Vortex ◽  
Preliminary Design ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Trailing Vortices ◽  
Computational Fluid Dynamics Cfd ◽  
Reynolds Averaged Navier Stokes

This paper extends the prescribed-wake vortex lattice method (VLM) to perform aerodynamic analysis of dual-rotor wind turbines (DRWTs). A DRWT turbine consists of a large, primary rotor placed co-axially behind a smaller, secondary rotor. The additional vortex system introduced by the secondary rotor of a DRWT is modeled while taking into account the singularities that can occur when the trailing vortices from the secondary (upstream) rotor interact with the bound vortices of the main (downstream) rotor. Pseudo-steady assumption is invoked, and averaging over multiple relative rotor positions is performed to account for the primary and secondary rotors operating at different rotational velocities. The VLM solver is first validated against experiments and blade element momentum theory results for a conventional, single-rotor turbine. The solver is then verified for two DRWT designs against results from two computational fluid dynamics (CFD) methods: (1) Reynolds-averaged Navier–Stokes CFD with an actuator disk representation of the turbine rotors and (2) large-eddy simulations with an actuator line model. Radial distributions of sectional torque force and angle of attack show reasonable agreement between the three methods. Results of parametric sweeps performed using VLM agree qualitatively with the Reynolds-averaged Navier–Stokes (RANS) CFD results demonstrating that the proposed VLM can be used to guide preliminary design of DRWTs.

Experimental and Numerical Analysis of a Motorcycle Air Intake System Aerodynamics and Performance

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan
Keyword(s):  
Combustion Process ◽  
Three Dimensional ◽  
Engine Performance ◽  
Internal Flow ◽  
Rapid Expansion ◽  
Navier Stokes ◽  
Turbulent Fluctuation ◽  
Ansys Fluent ◽  
Induction System ◽  
Acceleration And Deceleration

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.

Mechanism and Flow Control on the Mismatching of Impeller and Vaned Diffuser Caused by Inlet Prewhirl for Centrifugal Compressors

2016 ◽  
Author(s):  
Qiangqiang Huang ◽  
Xinqian Zheng ◽  
Aolin Wang
Keyword(s):  
Flow Control ◽  
Control Method ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Vaned Diffuser ◽  
Inlet Distortion ◽  
Computational Fluid Dynamics Cfd ◽  
Stagger Angle ◽  
Good Agreement ◽  
Matching Relation

Air often flows into compressors with inlet prewhirl, because it will obtain a circumferential component of velocity via inlet distortion or swirl generators such as inlet guide vanes. A lot of research has shown that inlet prewhirl does influence the characteristics of components, but the change of the matching relation between the components caused by inlet prewhirl is still unclear. This paper investigates the influence of inlet prewhirl on the matching of the impeller and the diffuser and proposes a flow control method to cure mismatching. The approach combines steady three-dimensional Reynolds-averaged Navier-Stokes (RANS) simulations with theoretical analysis and modeling. The result shows that a compressor whose impeller and diffuser match well at zero prewhirl will go to mismatching at non-zero prewhirl. The diffuser throat gets too large to match the impeller at positive prewhirl and gets too small for matching at negative prewhirl. The choking mass flow of the impeller is more sensitive to inlet prewhirl than that of the diffuser, which is the main reason for the mismatching. To cure the mismatching via adjusting the diffuser vanes stagger angle, a one-dimensional method based on incidence matching has been proposed to yield a control schedule for adjusting the diffuser. The optimal stagger angle predicted by analytical method has good agreement with that predicted by computational fluid dynamics (CFD). The compressor is able to operate efficiently in a much broader flow range with the control schedule. The flow range, where the efficiency is above 80%, of the datum compressor and the compressor only employing inlet prewhirl and no control are just 25.3% and 31.8%, respectively. For the compressor following the control schedule, the flow range is improved up to 46.5%. This paper also provides the perspective of components matching to think about inlet distortion.

scholarly journals Three-Dimensional Navier–Stokes Analysis and Redesign of an Imbedded Bellmouth Nozzle in a Turbine Cascade Inlet Section

1996 ◽  
Vol 118 (3) ◽  
pp. 529-535 ◽  
Author(s):  
P. W. Giel ◽  
J. R. Sirbaugh ◽  
I. Lopez ◽  
G. J. Van Fossen
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Inlet Section ◽  
Turbine Cascade ◽  
Blade Cascade ◽  
Inlet Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Transonic Turbine ◽  
Flow Nonuniformity

Experimental measurements in the inlet of a transonic turbine blade cascade showed unacceptable pitchwise flow nonuniformity. A three-dimensional, Navier–Stokes computational fluid dynamics (CFD) analysis of the imbedded bellmouth inlet in the facility was performed to identify and eliminate the source of the flow nonuniformity. The blockage and acceleration effects of the blades were accounted for by specifying a periodic static pressure exit condition interpolated from a separate three-dimensional Navier–Stokes CFD solution of flow around a single blade in an infinite cascade. Calculations of the original inlet geometry showed total pressure loss regions consistent in strength and location to experimental measurements. The results indicate that the distortions were caused by a pair of streamwise vortices that originated as a result of the interaction of the flow with the imbedded bellmouth. Computations were performed for an inlet geometry that eliminated the imbedded bellmouth by bridging the region between it and the upstream wall. This analysis indicated that eliminating the imbedded bellmouth nozzle also eliminates the pair of vortices, resulting in a flow with much greater pitchwise uniformity. Measurements taken with an installed redesigned inlet verify that the flow nonuniformity has indeed been eliminated.

Turbine Airfoil Heat Transfer Predictions Using CFD

2005 ◽  
Author(s):  
Anil K. Tolpadi ◽  
James A. Tallman ◽  
Lamyaa El-Gabry
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulence Modeling ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Navier Stokes ◽  
Design System ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Airfoils ◽  
Typical Design

Conventional heat transfer design methods for turbine airfoils use 2-D boundary layer codes (BLC) combined with empiricism. While such methods may be applicable in the mid span of an airfoil, they would not be very accurate near the end-walls and airfoil tip where the flow is very three-dimensional (3-D) and complex. In order to obtain accurate heat transfer predictions along the entire span of a turbine airfoil, 3-D computational fluid dynamics (CFD) must be used. This paper describes the development of a CFD based design system to make heat transfer predictions. A 3-D, compressible, Reynolds-averaged Navier-Stokes CFD solver with k-ω turbulence modeling was used. A wall integration approach was used for boundary layer prediction. First, the numerical approach was validated against a series of fundamental airfoil cases with available data. The comparisons were very favorable. Subsequently, it was applied to a real engine airfoil at typical design conditions. A discussion of the features of the airfoil heat transfer distribution is included.

Database of Sail Shapes vs. Sail Performance and Validation of Numerical Calculation for Upwind Condition

2007 ◽  
Author(s):  
Yutaka Masuyama ◽  
Yusuke Tahara ◽  
Toichi Fukasawa ◽  
Naotoshi Maeda
Keyword(s):  
Numerical Method ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Numerical Calculations ◽  
Navier Stokes ◽  
Coupling Scheme ◽  
Aerodynamic Coefficients ◽  
Lattice Method ◽  
Cfd Method

Database of full-scale three-dimensional sail shapes are presented with the aerodynamic coefficients for the upwind condition of IMS type sails. Three-dimensional shape data are used for the input of numerical calculations and the results are compared with the measured sail performance. The sail shapes and performance are measured using a sail dynamometer boat Fujin. The Fujin is a 34-foot LOA boat, in which load cells and charge coupled devices (CCD) cameras are installed to measure the sail forces and shapes simultaneously. The sailing conditions of the boat, such as boat speed, heel angle, wind speed, wind angle, and so on, are also measured. The tested sail configurations are as follows: mainsail with 130% jib, mainsail with 75% jib and mainsail alone. Sail shapes are measured at several height positions. The measured shape parameters are chord length, maximum draft, maximum draft position, entry angle at the luff and exit angle at the leech. From these parameters three-dimensional coordinates of the sails are calculated by interpolation. These three-dimensional coordinates are tabulated with the aerodynamic coefficients. Numerical calculations are performed using the measured sail shapes. The calculation methods are of two types; Reynolds-averaged Navier-Stokes (RANS)-based CFD and vortex lattice methods (VLM). A multi-block RANS-based CFD method was developed by one of the authors and is capable of predicting viscous flows and aerodynamic forces for complicated sail configuration for upwind as well as downwind conditions. Important features of the numerical method are summarized as follows: a Finite- Analytic scheme to discretize transport equations, a PISO type velocity-pressure coupling scheme, multi-block domain decomposition capability, and several choices of turbulence models depending on flows of interest. An automatic grid generation scheme is also included. Another calculation method, the vortex lattice method is also adopted. In this case, step-by-step calculations are conducted to attain the steady state of the sail in steady wind. Wake vortices are generated step-by-step, which flow in the direction of the local velocity vector. These calculated sail forces are compared with the measured one, and the validity of the numerical method is studied. The sail shape database and comparison with numerical calculations will provide a good benchmark for the sail performance analysis of the upwind condition of IMS type sails.

scholarly journals Numerical and Experimental Estimation of the Efficiency of a Quadcopter Rotor Operating at Hover

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 261 ◽  
Author(s):  
Andres G. ◽  
Juan S. ◽  
Omar López ◽  
Laura Suárez C, ◽  
Jaime A. Escobar
Keyword(s):  
Pressure Coefficient ◽  
Tip Vortex ◽  
Small Scale ◽  
Viscous Effects ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Values ◽  
Thrust And Torque

Globalization has led to an increase in the use of small copters for different activities such as geo-referencing, agricultural fields monitoring, survillance, among others. This is the main reason why there is a strong interest in the performance of small-scale propellers used in unmanned aerial vehicles. The flow developed by rotors is complex and the estimation of its aerodynamic performance is not a trivial process. In addition, viscous effects, when the rotor operates at low Reynolds, affect its performance. In the present paper, two different computational methods, Computational Fluid Dynamics (CFD) and the Unsteady Vortex Lattice Method (UVLM) with a viscous correction, were used to study the performance of an isolated rotor of a quadcopter flying at hover. The Multi Reference Frame model and transition S S T κ - ω turbulence model were used in the CFD simulations. The tip vortex core growth was used to account for the viscous effects in the UVLM. The wake structure, pressure coefficient, thrust and torque predictions from both methods are compared. Thrust and torque results from simulations were validated by means of experimental results of a characterization of a single rotor. Finally, figure of merit of the rotor is evaluated showing that UVLM overestimates the efficiency of the rotor; meanwhile, CFD predictions are close to experimental values.

scholarly journals Numerical Study of the Internal Flow Field of a Centrifugal Impeller

1994 ◽  
Author(s):  
Mou-jin Zhang ◽  
Chuan-gang Gu ◽  
Yong-miao Miao
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Internal Flow ◽  
Staggered Grid ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
High Reynolds

The complex three-dimensional flow field in a centrifugal impeller with low speed is studied in this paper. Coupled with high–Reynolds–number k–ε turbulence model, the fully three–dimensional Reynolds averaged Navier–Stokes equations are solved. The Semi–Implicit Method for Pressure–Linked Equations (SIMPLE) algorithm is used. And the non–staggered grid arrangement is also used. The computed results are compared with the available experimental data. The comparison shows good agreement.

Thruster and FPSO Hull Interaction

2014 ◽  
Author(s):  
Ye Tian ◽  
Spyros A. Kinnas
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Computational Efficiency ◽  
Vortex Lattice ◽  
Numerical Results ◽  
Navier Stokes ◽  
Dynamic Positioning ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Number Of Cells

A hybrid method which couples a Vortex-Lattice Method (VLM) solver and a Reynolds-Averaged Navier-Stokes (RANS) solver is applied to simulate the interaction between a Dynamic Positioning (DP) thruster and an FPSO hull. The hybrid method could significantly reduce the number of cells to fifth of that in a full blown RANS simulation and thus greatly enhance the computational efficiency. The numerical results are first validated with available experimental data, and then used to assess the significance of the thruster/hull interaction in DP systems.

Sign in / Sign up

Export Citation Format

Share Document