scholarly journals A Parametric Design Method for Hybrid Airfoils for Icing Wind Tunnel Test

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Zhao Li ◽  
Guang-jun Yang ◽  
Xiao-yan Tong ◽  
Feng Jiang
Keyword(s):  
Flow Field ◽  
Parametric Design ◽  
Design Method ◽  
Pressure Coefficient ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Full Scale ◽  
Navier Stokes ◽  
Ice Accretion ◽  
Multiple Control

The size of aircraft models that can be tested in icing wind tunnels is limited by the dimensions of the facilities in present; it is an effective method to replace the large model with a hybrid airfoil to carry out the experiment. A design method of multiple control points for hybrid airfoil based on the similarity of flow field in the leading edge of airfoil is proposed. Aiming at generating the full-scale flow field and ice accretion on the leading edge, multiobjective genetic optimization algorithm is used to design the hybrid airfoil under different conditions by combining the airfoil parameterization and solution of spatial constraint. Pressure tests of hybrid airfoils are carried out and compared with the leading edge pressure of the corresponding full-scale airfoils. The design and experimental results show that the pressure coefficient deviation between the hybrid airfoils designed and the corresponding full-scale airfoil in the 15% chord length range of the leading edge is within 4%. Finally, the vortex distribution and ice accretion process of the two airfoils were simulated by the unsteady Reynolds-averaged-Navier–Stokes (URANS) equations and multistep ice numerical method; it is shown that the hybrid airfoil can provide the same vortex distribution and ice accretion with the full-scale airfoil.

Aerodynamic Design and Optimization of Pipe Diffuser for a High-Loading Centrifugal Compressor

2017 ◽  
Author(s):  
Xi Yang ◽  
Dong-hai Jin ◽  
Xing-min Gui
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Simulation Software ◽  
Field Analysis ◽  
Superior Performance ◽  
Critical Cross Section ◽  
Isentropic Efficiency ◽  
Vane Diffuser

Pipe diffuser draws more attentions these years as the stage pressure ratio and loads grow, since it is known that the pipe diffuser has a superior performance to the traditional vane diffuser as the diffuser inlet flow field is transonic or supersonic. Generally speaking, when the pressure ratio is high enough to give rise to the emergence of a critical cross-section, it would usually be in the diffuser, closing to the leading edge other than in the impeller. Therefore, the diffuser would have a significant impact on stage choke margin and its performance while be difficult to design and to match the impeller with satisfaction. To address the problem, a preliminary geometry design method for pipe diffuser is presented in this paper. In this paper, the performance and flow field analysis are based on numerical simulation carried out by Numeca, a commercial simulation software. For verified the calculated results′ reliability and grid independence, corresponding calculations and comparisons are conducted and discussed. Then, the performance of stage with pipe diffuser is compared with the stage with vane diffuser. Next, the specific effects of incidence on the performance and flow field are analyzed and discussed respectively. At last, an optimized aerodynamic structure of pipe diffuser is presented. As shown in the CFD results, the stage peak isentropic efficiency can reach up to 83.65% with the stage total pressure ratio slightly increased from 6.50 to 6.78, which means 4.29% of isentropic efficiency was raised by substituting the pipe diffuser for the vane diffuser.

Transient Response Study on Rolling Effectiveness of Multiple Control Surfaces

2002 ◽  
Author(s):  
Deman Tang ◽  
Aiqin Li ◽  
Earl H. Dowell
Keyword(s):  
Transient Response ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Control Surface ◽  
Multiple Control ◽  
Wing Model ◽  
Aerodynamic Model ◽  
Control Surfaces ◽  
Dry Friction Damping

In the present paper, a transient response study of the effectiveness of trailing and leading edge control surfaces has been made for a rolling wing-fuselage model. An experimental model and wind tunnel test are used to assess the theoretical results. The theoretical model includes the inherently nonlinear dry friction damping moment that is present between the spindle support and the experimental aeroelastic wing model. The roll trim equation of motion and the appropriate aeroelastic equations are solved for different combinations of leading and trailing edge control surface rotations using a reduced order aerodynamic model based upon the fluid eigenmodes of three dimensional vortex lattice aerodynamic theory. The present paper provides new insights into the transient dynamic behavior and design of an adaptive aeroelastic wing using trailing and leading edge control surfaces.

Inverse Design and Optimization of a Return Channel for a Multistage Centrifugal Compressor

2004 ◽  
Vol 126 (5) ◽  
pp. 799-806 ◽  
Author(s):  
A´rpa´d Veress ◽  
Rene´ Van den Braembussche
Keyword(s):  
Design Method ◽  
Design Procedure ◽  
Leading Edge ◽  
Secondary Flows ◽  
Inverse Design ◽  
Navier Stokes ◽  
Design And Optimization ◽  
The Cross ◽  
Return Channel ◽  
The Impact

The design and optimization of a multistage radial compressor vaneless diffuser, cross-over and return channel is presented. An analytical design procedure for 3D blades with prescribed load distribution is first described and illustrated by the design of a 3D return channel vane with leading edge upstream of the cross-over. The analysis by means of a 3D Navier–Stokes solver shows a substantial improvement of the return channel performance in comparison with a classical 2D channel. Most of the flow separation inside and downstream of the cross-over could be avoided in this new design. The geometry is further improved by means of a 3D inverse design method to smooth the Mach number distribution along the vanes at hub and shroud. The Navier–Stokes analysis shows a rather modest impact on performance but the calculated velocity distribution indicates a more uniform flow and hence a larger operating range can be expected. The impact of vane lean on secondary flows is investigated and further performance improvements have been obtained with negative lean.

scholarly journals Aerodynamic study of a suspension bridge deck by CFD simulations, wind tunnel tests and full-scale observations

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wide Range

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

scholarly journals Scaling Method of the Rotating Blade of a Wind Turbine for a Rime Ice Wind Tunnel Test

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 627 ◽  
Author(s):  
Yan Li ◽  
Ce Sun ◽  
Yu Jiang ◽  
Fang Feng
Keyword(s):  
Heat Transfer ◽  
Wind Tunnel ◽  
Large Scale ◽  
Wind Tunnel Test ◽  
Full Scale ◽  
Similar Degree ◽  
Transfer Model ◽  
Ice Accretion ◽  
Water Droplets ◽  
Scaling Method

In order to research the law of rime ice accretion on different scaling blades surface, a new rime ice scaling method was proposed in this research. According to previous research, there are three kinds of ice types on blade surfaces: rime ice, glaze ice and mixed ice. Under the condition of rime ice, both the freezing fraction and the coefficient of heat transfer between super-cold water droplets and blade are 100%. The heat transfer model of rime ice is simpler than that of glaze ice and mixed ice. In this research, the scaling parameters including flow field, water droplets, temperature, pressure and rotating parameters were defined. The Weber number (We) based on water film thickness as an important parameter was applied in this study. The rotating parameters including rotating speed and radius had been added into the icing scaling method. To verify the effectiveness of the new rime ice scaling method, icing wind tunnel tests were carried out. The NACA0018 airfoil was used for the test blade. Two kinds of scale chord blades were selected, the chord of full-scale blade was 200 mm and of subscale blade was 100 mm. The test temperature was −15 °C. The ice accretion on different scale blades surface were captured by high-speed camera and the icing shapes of different scaling blades were obtained. To quantitatively analyze the similar degree of icing shapes on different scale blades, an evaluation method which included similar degree (Sim) was established based on the typical characteristic parameters proposed by previous research. The results show that the icing shapes of subscale blades are similar to that of full-scale blades. The similar degree is between 75.22% and 93.01%. The icing wind tunnel test indicates that the new rime ice scaling method is an effective method to study the rime ice of large scale rotating blades. This study can be used as a reference for research on anti-icing and de-icing technologies for large-scale HAWTs (Horizontal Axis Wind Turbines).

Aerodynamic Design of Turbomachinery Blading in Three-Dimensional Flow: An Application to Radial Inflow Turbines

1993 ◽  
Vol 115 (3) ◽  
pp. 602-613 ◽  
Author(s):  
Y. L. Yang ◽  
C. S. Tan ◽  
W. R. Hawthorne
Keyword(s):  
Parametric Design ◽  
Design Method ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Turbine Rotor ◽  
Computational Method ◽  
Navier Stokes ◽  
Design Calculation ◽  
Analysis Tool ◽  
Turbine Wheel

A computational method based on a theory for turbomachinery blading design in three-dimensional inviscid flow is applied to a parametric design study of a radial inflow turbine wheel. As the method requires the specification of swirl distribution, a technique for its smooth generation within the blade region is proposed. Excellent agreements have been obtained between the computed results from this design method and those from direct Euler computations, demonstrating the correspondence and consistency between the two. The computed results indicate the sensitivity of the pressure distribution to a lean in the stacking axis and a minor alteration in the hub/shroud profiles. Analysis based on a Navier–Stokes solver shows no breakdown of flow within the designed blade passage and agreement with that from a design calculation; thus the flow in the designed turbine rotor closely approximates that of an inviscid one. These calculations illustrate the use of a design method coupled to an analysis tool for establishing guidelines and criteria for designing turbomachinery blading.

Nonaxisymmetric Turbine End Wall Design: Part I— Three-Dimensional Linear Design System

1999 ◽  
Vol 122 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Neil W. Harvey ◽  
Martin G. Rose ◽  
Mark D. Taylor ◽  
Shahrokh Shahpar ◽  
Jonathan Hartland ◽  
...  
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Design System ◽  
Linear Superposition ◽  
Turbine Rotor Blade ◽  
End Wall

A linear design system, already in use for the forward and inverse design of three-dimensional turbine aerofoils, has been extended for the design of their end walls. This paper shows how this method has been applied to the design of a nonaxisymmetric end wall for a turbine rotor blade in linear cascade. The calculations show that nonaxisymmetric end wall profiling is a powerful tool for reducing secondary flows, in particular the secondary kinetic energy and exit angle deviations. Simple end wall profiling is shown to be at least as beneficial aerodynamically as the now standard techniques of differentially skewing aerofoil sections up the span, and (compound) leaning of the aerofoil. A design is presented that combines a number of end wall features aimed at reducing secondary loss and flow deviation. The experimental study of this geometry, aimed at validating the design method, is the subject of the second part of this paper. The effects of end wall perturbations on the flow field are calculated using a three-dimensional pressure correction based Reynolds-averaged Navier–Stokes CFD code. These calculations are normally performed overnight on a cluster of work stations. The design system then calculates the relationships between perturbations in the end wall and resulting changes in the flow field. With these available, linear superposition theory is used to enable the designer to investigate quickly the effect on the flow field of many combinations of end wall shapes (a matter of minutes for each shape). [S0889-504X(00)00902-8]

scholarly journals Wing Section Optimization for Supersonic Viscous Flow

1998 ◽  
Vol 120 (1) ◽  
pp. 102-108 ◽  
Author(s):  
Cem C. Item ◽  
Oktay Baysal
Keyword(s):  
Optimization Problem ◽  
Stokes Equations ◽  
Design Method ◽  
Leading Edge ◽  
Adverse Pressure Gradient ◽  
Navier Stokes ◽  
Test Cases ◽  
Aerodynamic Optimization ◽  
Wing Section ◽  
Problem Formulations

To improve the performance of a highly swept supersonic wing, it is desirable to have an automated design method that also includes a higher fidelity to the flow physics. With this impetus, an aerodynamic optimization methodology incorporating the thin-layer Navier-Stokes equations and sensitivity analysis had previously been developed. Prior to embarking upon the full wing design task, the present investigation concentrated on the identification of effective optimization problem formulations and testing the feasibility of the employed methodology, by defining two-dimensional test cases. Starting with two distinctly different initial airfoils, two independent optimizations resulted in shapes with similar features: cambered, parabolic profiles with sharp leading- and trailing-edges. Secondly, an outboard wing section normal to the subsonic portion of the leading edge, which had a high normal angle-of attack, was considered. The optimization resulted in a shape with twist and camber that eliminated the adverse pressure gradient, hence, exploiting the leading-edge thrust. The wing section shapes obtained in all the test cases included the features predicted by previous studies. This was considered as a strong indication that the flow field analyses and sensitivity coefficients were computed and provided to the present gradient-based optimizer correctly. Also, from the results of the present study, effective optimization problem formulations could be deduced to start a full wing shape optimization.

scholarly journals Inverse Design of Centrifugal Compressor Vaned Diffusers in Inlet Shear Flows

1994 ◽  
Author(s):  
M. Zangeneh
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Design Method ◽  
Internal Flow ◽  
Inviscid Flow ◽  
Inverse Design ◽  
Navier Stokes ◽  
Inlet Flow ◽  
Blade Thickness ◽  
The Difference

A 3D inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modelled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and non-uniform inlet flow diffusers is found to be most significant from 50% chord to the trailing edge region. The flow through both diffusers are computed by using Denton’s 3D inviscid Euler solver and Dawes’ 3D Navier-Stokes solver under sheared inflow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.

Pressure Distributions on Sails Investigated Using Three Methods: On-Water Measurements, Wind-Tunnel Measurements, and Computational Fluid Dynamics

2011 ◽  
Author(s):  
Ignazio Maria Viola ◽  
Richard G. J. Flay
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Full Scale ◽  
Navier Stokes ◽  
Pressure Measurements ◽  
Wind Tunnel Tests ◽  
Pressure Distributions ◽  
Unstable Environment ◽  
Full Scale Tests ◽  
Good Agreement

The main results of a two-year project aimed at comparing full-scale tests, wind tunnel tests, and numerical analysis predictions are presented. Pressure measurements were obtained from both full-scale tests and wind-tunnel tests, in upwind and downwind conditions. The upwind wind tunnel test condition was modelled using a Vortex Lattice code, while the downwind wind-tunnel test was modelled using a Navier-Stokes code. The pressures obtained from the three different methods are compared on three horizontal sections of the headsail, mainsail, and asymmetric spinnaker. In general the pressures from the three experiments showed good agreement. In particular, very good agreement was obtained between the numerical computations and the wind tunnel test results. Conversely, the results from the downwind full-scale pressure measurements showed less similarity due to a slightly tightened trim being used for the spinnaker in the on-water tests. Full-scale tests allow the action of unsteadiness due to the wind, wave and yacht movements to affect the results. This unstable environment caused the asymmetric spinnaker to move around, and a tightened trim was required to prevent the spinnaker from collapsing.

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