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Article
Publication date: 20 May 2020

Roy V. Paul, Kriparaj K.G. and Tide P.S.

The purpose of this study is to investigate the aerodynamic characteristics of subsonic jet emanating from corrugated lobed nozzle.

Abstract

Purpose

The purpose of this study is to investigate the aerodynamic characteristics of subsonic jet emanating from corrugated lobed nozzle.

Design/methodology/approach

Numerical simulations of subsonic turbulent jets from corrugated lobed nozzles using shear stress transport k-ω turbulence model have been carried out. The analysis was carried out by varying parameters such as lobe length, lobe penetration and lobe count at a Mach number of 0.75. The numerical predictions of axial and radial variation of the mean axial velocity, uu′ ¯ and vv′ ¯ have been compared with experimental results of conventional round and chevron nozzles reported in the literature.

Findings

The centreline velocity at the exit of the corrugated lobed nozzle was found to be lower than the velocity at the outer edges of the nozzle. The predicted potential core length is lesser than the experimental results of the conventional round nozzle and hence the decay in centreline velocity is faster. The centreline velocity increases with the increase in lobe length and becomes more uniform at the exit. The potential core length increases with the increase in lobe count and decreases with the increase in lobe penetration. The turbulent kinetic energy region is narrower with early appearance of a stronger peak for higher lobe penetration. The centreline velocity degrades much faster in the corrugated nozzle than the chevron nozzle and the peak value of Reynolds stress appears in the vicinity of the nozzle exit.

Practical implications

The corrugated lobed nozzles are used for enhancing mixing without the thrust penalty inducing better acoustic benefits.

Originality/value

The prominent features of the corrugated lobed nozzle were obtained from the extensive study of variation of flow characteristics for different lobe parameters after making comparison with round and chevron nozzle, which paved the way to the utilization of these nozzles for various applications.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 31 October 2018

Mubarak A.K. and Tide P.S.

The purpose of this paper is to design a double parabolic nozzle and to compare the performance with conventional nozzle designs.

Abstract

Purpose

The purpose of this paper is to design a double parabolic nozzle and to compare the performance with conventional nozzle designs.

Design/methodology/approach

The throat diameter and divergent length for Conical, Bell and Double Parabolic nozzles were kept same for the sake of comparison. The double parabolic nozzle has been designed in such a way that the maximum slope of the divergent curve is taken as one-third of the Prandtl Meyer (PM) angle. The studies were carried out at Nozzle Pressure Ratio (NPR) of 5 and also at design conditions (NPR = 3.7). Experimental measurements were carried out for all the three nozzle configurations and the performance parameters compared. Numerical simulations were also carried out in a two-dimensional computational domain incorporating density-based solver with RANS equations and SST k-ω turbulence model.

Findings

The numerical predictions were found to be in reasonable agreement with the measured experimental values. An enhancement in thrust was observed for double parabolic nozzle when compared with that of conical and bell nozzles.

Research limitations/implications

Even though the present numerical simulations were capable of predicting shock cell parameters reasonably well, shock oscillations were not captured.

Practical implications

The double parabolic nozzle design has enormous practical importance as a small increase in thrust can result in a significant gain in pay load.

Social implications

The thrust developed by the double parabolic nozzle is seen to be on the higher side than that of conventional nozzles with better fuel economy.

Originality/value

The overall performance of the double parabolic nozzle is better than conical and bell nozzles for the same throat diameter and length.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 1 April 1932

J.H. Parkin

IF the most effective use is to be made of aircraft in Canada in the future, adequate research facilities must be provided to assist designers and the industry to develop…

Abstract

IF the most effective use is to be made of aircraft in Canada in the future, adequate research facilities must be provided to assist designers and the industry to develop improved aircraft, suited to the conditions and requirements of the country, and to solve the problems arising in Canadian aviation. The National Research Council has, therefore, with the approval of the Sub‐Committee of the Privy Council for Scientific and Industrial Research, undertaken to provide, in the National Research Laboratories now being established in Ottawa, facilities for aeronautical research.

Details

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

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Article
Publication date: 1 January 1992

A. Hall and M. Hemming

With the growing demand for more complex PCBs with tighter tolerances, there is a need to improve the production capability of solder masks, together with etch and plating resists.

Abstract

With the growing demand for more complex PCBs with tighter tolerances, there is a need to improve the production capability of solder masks, together with etch and plating resists.

Details

Circuit World, vol. 18 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 November 1975

A single dot temperature indicating device, a self‐adhesive disc, which monitors temperature rise by changing colour if a particular temperature has been reached or…

Abstract

A single dot temperature indicating device, a self‐adhesive disc, which monitors temperature rise by changing colour if a particular temperature has been reached or exceeded, has been developed by Synthetic & Industrial Finishes Ltd, Imperial Way, Watford, Herts, manufacturers of the Thermindex range of temperature indicating paints and adhesive strips. The Thermindex single dot indicators show the temperature of components or products during manufacture or processing, transportation, storage and ultimate use. They are available for temperatures between 37.5°C and 200°C and are supplied in multiples of 100 (four sheets of 25 each). They have an accuracy of ±1°C.

Details

Pigment & Resin Technology, vol. 4 no. 11
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 July 1954

The primary objective in the design of the reversers described and illustrated was to obtain a device inherently safe and reliable, using simple locks and mechanisms. A…

Abstract

The primary objective in the design of the reversers described and illustrated was to obtain a device inherently safe and reliable, using simple locks and mechanisms. A secondary, but important requirement was operational flexibility, with the proviso that the device should be used for ground control only. Additionally the installation should not adversely affect the output of the power unit when the former is not in operation.

Details

Aircraft Engineering and Aerospace Technology, vol. 26 no. 7
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 9 April 2018

Marco Anilli, Ali Gökhan Demir and Barbara Previtali

The purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a…

Abstract

Purpose

The purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a whole production chain composed of an additive manufacturing (AM) and consecutive finishing processes together. Beyond the metrological and flow-related characterization of the produced nozzles, functional analysis on the use of the produced nozzles are carried out through laser cutting experiments.

Design/methodology/approach

SLM experiments were carried out to determine the correct compensation factor to achieve a desired nozzle diameter on steel with known processibility by SLM and using standard nozzle geometries for comparative purposes. The produced nozzles are finished through electrochemical machining (ECM) and abrasive flow machining (AFM). The performance of nozzles produced via additive manufacturing (AM) are compared to conventional ones on an industrial laser cutting system through cutting experiments with a 6 kW fibre laser. The produced nozzles are characterized in terms of pressure drop and flow dynamics through Schlieren imaging.

Findings

The manufacturing chain was regulated to achieve 1 mm diameter nozzles after consecutive post processing. The average surface roughness could be lowered by approximately 80 per cent. The SLM produced single chamber nozzles would perform similarly to conventional nozzles during the laser cutting of 1 mm mild steel with nitrogen. The double chamber nozzles could provide complete cuts with oxygen on 5 mm-thick mild steel only after post-processing. Post-processing operations proved to decrease the pressure drop of the nozzles. Schlieren images showed jet constriction at the nozzle outlet on the as-built nozzles.

Originality/value

In this work, the use of an additive manufacturing process is assessed together with suitable finishing and functional analysis of the related application to provide a complete production and evaluation chain. The results show how the finishing processes should be allocated in an AM-based production chain in a broader vision. In particular, the results confirm the functionality for designing more complex nozzle geometries for laser cutting, exploiting the flexibility of SLM process.

Details

Rapid Prototyping Journal, vol. 24 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 July 1962

J. Fletcher

The stability and control systems adopted by the Bell Aircraft Corporation and for the Short S.C.1 are discussed with reference to efficiency, and the importance of low…

Abstract

The stability and control systems adopted by the Bell Aircraft Corporation and for the Short S.C.1 are discussed with reference to efficiency, and the importance of low loss nozzle systems is emphasized. The form of auto‐stabilization and its application to the aircraft control system are to sonic extent governed by the operating requirements of the V.T.O.L. aircraft. Lift engine intake problems and the interaction effects of the airflow passing through the lift engines on the airframe as a whole are considered at length, along with ground effects and novel model testing techniques. The author concludes that much model and full‐scale research is still needed to investigate further the many problems which remain and which can critically affect the feasibility of projects for operational use.

Details

Aircraft Engineering and Aerospace Technology, vol. 34 no. 7
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 8 June 2021

M. Balasubramanian and S. Madhu

The purpose of the study is to machine the composites at lower machining time with higher accuracy without causing delamination.

Abstract

Purpose

The purpose of the study is to machine the composites at lower machining time with higher accuracy without causing delamination.

Design/methodology/approach

Abrasive jet machining is the technology appropriate for machining composite materials to obtain good dimensional accuracy without causing de-lamination. The central composite design was followed in deciding the number of experiments to be carried out.

Findings

The influence of abrasive jet machining process parameters on machining time, material removal rate (MRR) and kerf characteristics were investigated. The experimental results proved the newly designed internal threaded nozzle increased MRR, thereby reducing the machining time.

Originality/value

Machining of glass fibre reinforced polymer (GFRP) is one of the challenging tasks given its non-linear and in-homogeneous properties. In this investigation, newly developed threaded and unthreaded nozzles in machining were used for making holes on the GFRP composites.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 1 January 1963

These details of British Patent Specifications are taken by permission from ‘Abridgments of Specifications—Patents for Inventions’. Copies of the full specifications are…

Abstract

These details of British Patent Specifications are taken by permission from ‘Abridgments of Specifications—Patents for Inventions’. Copies of the full specifications are obtainable from the Patent Office, 25 Southampton Buildings, London, W.C.2, price 4s. 6d. each.

Details

Aircraft Engineering and Aerospace Technology, vol. 35 no. 1
Type: Research Article
ISSN: 0002-2667

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