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Article
Publication date: 31 December 2020

Xing Xie, Zhenlin Li, Baoshan Zhu and Hong Wang

This study aims to complete the optimization design of a centrifugal impeller with both high aerodynamic efficiency and good structural machinability.

Abstract

Purpose

This study aims to complete the optimization design of a centrifugal impeller with both high aerodynamic efficiency and good structural machinability.

Design/methodology/approach

First, the design parameters were derived from the blade loading distribution and the meridional geometry in the impeller three-dimensional (3D) inverse design. The blade wrap angle at the middle span surface and the spanwise averaged blade angle at the blade leading edge obtained from inverse design were chosen as the machinability objectives. The aerodynamic efficiency obtained by computational fluid dynamics was selected as the aerodynamic performance objective. Then, using multi-objective optimization with the optimal Latin hypercube method, quadratic response surface methodology and the non-dominated sorting genetic algorithm, the trade-off optimum impellers with small blade wrap angles, large blade angles and high aerodynamic efficiency were obtained. Finally, computational fluid dynamics and computer-aided manufacturing were performed to verify the aerodynamic performance and structural machinability of the optimum impellers.

Findings

Providing the fore maximum blade loading distribution at both the hub and shroud for the 3D inverse design helped to promote the structural machinability of the designed impeller. A straighter hub coupled with a more curved shroud also facilitated improvement of the impeller’s structural machinability. The preferred impeller was designed by providing both the fore maximum blade loading distribution at a relatively straight hub and a curved shroud for 3D inverse design.

Originality/value

The machining difficulties of the designed high-efficiency impeller can be reduced by reducing blade wrap angle and enlarging blade angle at the beginning of impeller design. It is of practical value in engineering by avoiding the follow-up failure for the machining of the designed impeller.

Details

Engineering Computations, vol. 38 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 8 May 2018

Javier Martinez Suarez, Pawel Flaszynski and Piotr Doerffer

The purpose of this paper is to describe numerical investigations focused on the reduction of separation and the aerodynamic enhancement of wind turbine blades by a rod…

Abstract

Purpose

The purpose of this paper is to describe numerical investigations focused on the reduction of separation and the aerodynamic enhancement of wind turbine blades by a rod vortex generator (RVG).

Design/methodology/approach

A flow modelling approach through the use of a Reynolds-averaged Navier–Stokes solver is used. The numerical tools are validated with experimental data for the NREL Phase VI rotor and the S809 aerofoil. The effect of rod vortex generator’s (RVG) configuration on aerofoil aerodynamic performance, flow structure and separation is analysed. RVGs’ chordwise locations and spanwise distance are considered, and the optimum configuration of the RVG is applied to the wind turbine rotor.

Findings

Results show that streamwise vortices created by RVGs lead to modification of flow structure in boundary layer. As a result, the implementation of RVGs on aerofoil has proven to decrease the flow separation and enhance the aerodynamic performance of aerofoils. The effect on flow structure and aerodynamic performance has shown to be dependent on dimensions, chordwise location and spanwise distribution of rods. The implementation of devices with the optimum configuration has shown to increase aerodynamic performance and to significantly reduce separation for selected conditions. Application of rods to the wind turbine rotor has proven to avoid the spanwise penetration of flow separation where applied, leading to reduction of flow separation and to aerodynamic enhancement.

Originality/value

The proposed RVGs have shown potential to enhance the aerodynamic performance of wind turbine rotors and profiles, making devices an alternative solution to the classical vortex generators for wind turbine applications.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 27 March 2008

Hector Iacovides and Mehrdad Raisee

This paper aims to compute flow and heat transfer through a straight, orthogonally rotating duct, with ribs along the leading and trailing walls, in a staggered…

Abstract

Purpose

This paper aims to compute flow and heat transfer through a straight, orthogonally rotating duct, with ribs along the leading and trailing walls, in a staggered arrangement and at an angle of 45° to the main flow direction.

Design/methodology/approach

Flow computations have been produced using a 3D non‐orthogonal flow solver, with two two‐layer models of turbulence (an effective‐viscosity model and a second‐moment closure), in which across the near‐wall regions the dissipation rate of turbulence is obtained from the wall distance. Flow comparisons have been carried out for a Reynolds number of 100,000 and for rotation numbers of 0 (stationary) and 0.1. Temperature comparisons have been obtained for a Reynolds number of 36,000, a Prandtl number of 5.9 (water) and rotation numbers of 0 and 0.2 and also at a Prandtl number of 0.7 (air) and a rotation number of 0.

Findings

It was found that both two‐layer models returned similar flow and thermal predictions which are also in close agreement with the flow and thermal measurements. The flow and thermal developments are found to be dominated by the rib‐induced secondary motion, which leads to strong span‐wise variations in the mean flow and the local Nusselt number and to a uniform distribution of turbulence intensities across the duct. Rotation causes the development of stronger secondary motion along the pressure side of the duct and also the transfer of the faster fluid to this side. The thermal predictions, especially those of the second‐moment closure, reproduce the levels and most of the local features of the measured Nusselt number, but over the second half of the rib interval over‐predict the local Nusselt number.

Originality/value

The work contributes to the understanding of the flow and thermal development in cooling passages of gas turbine blades, and to the validation of turbulence models that can be used for their prediction, at both effective viscosity and second‐moment closure levels.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 18 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 July 1949

G.E.H. Rice

THE first practical application of a simplified form of aircraft structure was made by the Republic Aircraft Corp. in their production of the Seabee. This machine…

Abstract

THE first practical application of a simplified form of aircraft structure was made by the Republic Aircraft Corp. in their production of the Seabee. This machine dispensed with conventional ribs and used external chordwise corrugations instead. These were found to be perfectly satisfactory; they resisted the air loading and were stiff enough to prevent undue distortion of the cross‐section of the structure. For machines of higher speed, however, these corrugations, or ‘beads’ as they were called, would be objectionable and would have to be replaced by internal stiffeners fixed to the skin. This is the type of structure it is now proposed to analyse—a general view is shown in FIG. 1.

Details

Aircraft Engineering and Aerospace Technology, vol. 21 no. 7
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 March 1956

F.A. Woodward

A method is presented for calculating the aerodynamic forces acting on an elastic supersonic wing having arbitrarily swept straight leading edges and a supersonic trailing…

Abstract

A method is presented for calculating the aerodynamic forces acting on an elastic supersonic wing having arbitrarily swept straight leading edges and a supersonic trailing edge. The loads are presented in matrix form in terms of the geometrical incidence effective at given wing structural stations. It is thus possible, by combination with the corresponding structural matrix, to determine the steady state aeroelastic loading and final shape of the wing. It is shown how the distribution of loading associated with the placing of incidence on a small quadrilateral area within the wing plan form may be calculated. This loading is broken down into point loads acting at the required structural stations by graphical integration. The loading due to each small area is built up by superposing solutions obtained from linearized supersonic control surface theory. The sweep of the hinge line, and its relation to the wing Mach lines and leading edges are the main parameters of the problem. Twelve formulae are presented, giving the loading in each of the various regions likely to occur for practical wings. By a proper combination of the loads acting on symmetrically opposed stations on each side of the wing, the symmetric or anti‐symmetric aerodynamic matrix can be formed, corresponding to pitching and plunging, or rolling motions of the wing respectively.

Details

Aircraft Engineering and Aerospace Technology, vol. 28 no. 3
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 February 2001

Howard Smith

Describes preliminary structural design work on a notional uninhabited tactical aircraft (UTA), carried out at Cranfield University. UTAs are seen as an important future…

1162

Abstract

Describes preliminary structural design work on a notional uninhabited tactical aircraft (UTA), carried out at Cranfield University. UTAs are seen as an important future element of military fleets. A notional baseline requirement was derived, leading to the evolution of a design solution. The basic requirements for such a UTA are naturally highly classified but, although industry has been hesitant to comment, the baseline requirements and design solution developed herein are believed to be reasonable.

Details

Aircraft Engineering and Aerospace Technology, vol. 73 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 17 October 2018

Tomasz Kwiatkowski, Pawel Flaszyński and Jerzy Zoltak

The simulations of grid-resolved rod vortex generators (RVGs) require high computational cost and time. Additionally, the computational mesh topology must be adjusted to…

Abstract

Purpose

The simulations of grid-resolved rod vortex generators (RVGs) require high computational cost and time. Additionally, the computational mesh topology must be adjusted to rods geometries. The purpose of this study is to propose the new source term model for RVG.

Design/methodology/approach

The model was proposed by modification of Bender, Anderson, Yagle (BAY) model used to predict flows around different type of vortex generators (VGs) – vanes. Original BAY model was built on lifting line theory. The proposed model was implemented in ANSYS Fluent by means of the user-defined function technique. Additional momentum and energy sources are imposed to transport equations.

Findings

The computational results of source term model were validated against experimental data and numerical simulation results for grid-resolved rod. It was shown that modified BAY model can be successfully used for RVG in complex cases. An example of BAY model application for RVG on transonic V2C airfoil with strongly oscillating shock waves is presented. Aerodynamic performance predicted numerically by means of both approaches (grid resolved RVG and modeled) is in good agreement, what indicates application opportunity of the proposed model to complex cases.

Practical implications

Modified BAY model can be used to simulate the influence of RVGs in complex real cases. It allows for time/cost reduction if the location or distribution of RVG has to be optimized on a profile, wing or in the channel.

Originality/value

In the paper, the new modification of BAY model was proposed to simulate RVGs. The presented results are innovative because of original approach to model RVGs.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 9
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 31 July 2019

Guohua Zhang, Xueting Liu, Bengt Ake Sundén and Gongnan Xie

This study aims to clarify the mechanism of film hole location at the span-wise direction of an internal cooling channel with crescent ribs on the adiabatic film cooling…

Abstract

Purpose

This study aims to clarify the mechanism of film hole location at the span-wise direction of an internal cooling channel with crescent ribs on the adiabatic film cooling performance, three configurations are designed to observe the effects of the distance between the center of the ellipse and the side wall(Case 1, l = w/2, Case 2, l = w/3 and for Case 3, l = w/4).

Design/methodology/approach

Numerical simulations are conducted under two blowing ratios (i.e. 0.5 and 1) and a fixed cross-flow Reynolds number (Rec = 100,000) with a verified turbulence model.

Findings

It is shown that at low blowing ratio, reducing the distance increases the film cooling effectiveness but keeps the trend of the effectiveness unchanged, while at high blowing ratio, the characteristic is a little bit different in the range of 0 = x/D =10.

Research limitations/implications

These features could be explained by the fact that shrinking the distance between the hole and side wall induces a much smaller reserved region and vortex downstream the ribs and a lower resistance for cooling air entering the film hole. Furthermore, the spiral flow inside the hole is impaired.

Originality/value

As a result, the kidney-shaped vortices originating from the jet flow are weakened, and the target surface can be well covered, resulting in an enhancement of the adiabatic film cooling performance.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 August 2002

M. Wrona and E. Tuliszka‐Sznitko

The linear and non‐linear stability of an incompressible swept attachment‐line boundary layer are analysed, within the Görtler‐Hämmerlin framework. The system of…

Abstract

The linear and non‐linear stability of an incompressible swept attachment‐line boundary layer are analysed, within the Görtler‐Hämmerlin framework. The system of perturbation equations is solved using spectral collocation method based on Chebyshev polynomials. The global solution method utilised for solving the eigenproblem yields the full spectrum of the least damped waves. The influence of suction and blowing on critical Reynolds numbers is analysed. A comparison of the present paper linear solutions for both zero suction and a layer in which blowing and suction are applied with the Spalart's DNS solutions (obtained for small initial disturbances) shows very good agreement. The transition Reynolds numbers have been predicted using well known exp(n) method and results are compared with the experimental data of Powilleit.

Details

Aircraft Engineering and Aerospace Technology, vol. 74 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 June 1992

KAMEL M. AL‐KHALIL, THEO G. JR. KEITH and KENNETH J. DE WITT

A numerical solution for ‘running wet’ aircraft anti‐icing systems is developed. The model includes breakup of the water film, which exists in regions of direct…

Abstract

A numerical solution for ‘running wet’ aircraft anti‐icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modelled as a multi‐layer structure and the anti‐icing system used is of the thermal type utilizing hot air and/or electrical heating elements embedded within the layers. Details of the calculation procedure and the methods used are presented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 2 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

1 – 10 of 399