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Article
Publication date: 1 February 2022

Premkumar P.S., Nadaraja Pillai S. and Senthil Kumar C.

Pusher configured turbo-prop aircraft receive inadequate ram air cooling due to the lack of propeller slipstream, particularly during ground operations. However, flow entrainment…

130

Abstract

Purpose

Pusher configured turbo-prop aircraft receive inadequate ram air cooling due to the lack of propeller slipstream, particularly during ground operations. However, flow entrainment can be exploited to a greater extent by placing the oil-cooler duct close to downstream of the propeller at a suitable radial location. But this method has a detrimental effect on the propeller thrust. The purpose of this paper is to discuss the results of numerical simulations carried out to simulate the performance of the propeller with and without oil cooler.

Design/methodology/approach

In this paper, three-dimensional (3D) numerical simulations are carried out to simulate the propeller in a rotating domain using an unstructured grid. A computational fluid dynamics solver is put forward to analyze the effect of thrust loss by solving 3D Navier-Stokes equations using a second-order upwind finite-volume scheme. In this study, the impact of thrust loss incurred in the propeller flow field with and without oil cooler duct for three different locations at various rotational speeds is carried out to assess the propeller performance and to identify the optimum position to get a sufficient mass flow rate.

Findings

The findings from this study are simulated thrust values of an uninstalled five-bladed propeller of light transport aircraft (LTA) match well with original equipment manufacturer propeller thrust data. The tip speed velocities simulated for different operating conditions are in good agreement with the theoretical calculations. The influence of oil-cooler effect on the propeller flow field is less in low velocity to high-velocity operating condition due to flow transition from laminar to turbulent. The presence of the oil cooler, which influences the thrust loss, is studied at propeller upstream and downstream locations in detail for 30%, 40% and 50% of propeller radius cases.

Research limitations/implications

Simulations with finer and structured hexa grids can be applied to this problem to get closer results and save solver time as future work.

Practical implications

The recommended system is installed in the production standard aircraft of LTA. After installation oil cooler performance is better compared to the previous arrangement.

Originality/value

Research work about pusher aircraft is very limited. The problem addressed in this study is unique which resolves the major issue of pusher aircraft. This work highlights the difficulty involved in LTA engine oil cooling, and solution methodologies are also provided. Numerical simulation with oil-cooler assembly is a new area of research that gave the solution for this oil-cooling issue through various oil-cooler case studies.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 6
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 9 May 2022

E. Livya and S. Nadaraja Pillai

This paper aims to study the extended trailing edge airfoil for a range of angle of attack at different intensities of turbulence.

334

Abstract

Purpose

This paper aims to study the extended trailing edge airfoil for a range of angle of attack at different intensities of turbulence.

Design/methodology/approach

In this paper, an experimental study on NACA 0020 airfoil with thin extended trailing edge modification of amplitude of h = 0.1c, 0.2c and 0.3c at the Reynolds number of 2.14 × 105 are tested. The research was carried out for an angle of attack ranging from 0° = α = 35° for the turbulence intensity of 0.3%, 3%, 5%, 7% and 12%. From the experimental readings, the surface pressures are scanned using a Scanivalve (MPS2464) pressure scanner for a sampling frequency of 700 Hz. The scanned pressures are converted to aerodynamic force coefficient and the results are combined and discussed.

Findings

The airfoil with the extended trailing edge will convert the adverse pressure gradient to a plateau pressure zone, indicating the delayed flow separation. The CL value at higher turbulence intensity (TI = 12%) for the extended trailing edge over perform the base airfoil at the post-stall region. The maintenance of flow stability is observed from the spectral graph.

Practical implications

A thin elongated trailing edge attached to the conventional airfoil serves as a flow control device by delaying the stall and improving the lift characteristics. Additionally, extending the airfoil's trailing edge helps to manage the performance of the airfoil even at a high level of turbulence.

Originality/value

Distinct from existing studies, the presented results reveals how the extended trailing edge attached to the airfoil performs in the turbulence zone ranging from 0.3% to 12% of TI. The displayed pressure distribution explains the need for increasing trailing edge amplitude (h) and its impact on flow behaviour. The observation is that extended trailing edge airfoil bears to maintain the performance even at higher turbulence region.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 10
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 11 October 2023

Mano S. and Nadaraja Pillai S.

This study aims to investigate the effect of downstream characteristics of S809 wind turbine blade with various extended flat plate (EFP) configuration. Wind farms are recently…

121

Abstract

Purpose

This study aims to investigate the effect of downstream characteristics of S809 wind turbine blade with various extended flat plate (EFP) configuration. Wind farms are recently modified to improve the power production through placing number of wind turbines and locations.

Design/methodology/approach

A series of wind tunnel experiments were carried out to evaluate the downstream wake characteristics of the S809 airfoil attached with various EFP (EFP, A = 0.1C, 0.2C and 0.3C) at various angles of attack corresponding to free stream velocity Reynolds number (Re) = 2.11 × 105 and various turbulence intensity (TI = 5%, 7%, 10% and 12%).

Findings

For the S809 wind turbine blade attached with EFP, the downstream velocity ratio decreases with increasing in angle of attack and the velocity deficit decrease with increasing turbulence intensity (TI) up to TI = 10%. The wake intensity for the S809 wind turbine blade and S809 airfoil with 10% of chord EFP performs the same for each downstream location.

Practical implications

Placing the wind turbine in the wind park next to another wind turbine poses a potential challenge for the park power performance. This research addresses the characteristics of the downstream turbulence intensity profile modified with the EFP in the wind turbine blade which improves the downstream characteristics of the turbine in the wind park.

Originality/value

The downstream velocity ratio decreases with increasing angle of attack and the velocity deficit decrease with increasing turbulence intensity (TI) up to TI = 10%.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 10
Type: Research Article
ISSN: 1748-8842

Keywords

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