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Article
Publication date: 17 June 2019

Jafar Nejadali

Regenerative flow pumps are dynamic machines with the ability to develop high heads at low flow rates. Simplicity, compactness, stable features and low manufacturing costs…

Abstract

Purpose

Regenerative flow pumps are dynamic machines with the ability to develop high heads at low flow rates. Simplicity, compactness, stable features and low manufacturing costs make them interesting for many applications in industries. The purpose of this study is to present a new method for calculating the flow through regenerative pumps with bucket form blades to predict the performance curves by a cheap and easy-to-use way.

Design/methodology/approach

The analysis was carried out based on the geometric shape of a fluid particle trajectory in a regenerative turbomachine. The fluid particle path was assumed to be a helix wrapped into a torus. Loss models were considered and the results of predictions were compared with computational fluid dynamics (CFD) data.

Findings

The overall trend of performance curves resulted from presented model looked consistent with CFD data. However, there were slight differences in high and low flow coefficients. The results showed that the predicted geometric shape of the flow path with the presented model (a helix wrapped into a torus) was not consistent with CFD results at high flow coefficients. Due to the complexity and turbulence of the fluid flow and errors in the calculation of losses, as well as slip factor, there was a discrepancy between the results of the presented model and numerical simulation, especially in high and low flow coefficients.

Originality/value

The analysis was carried out based on the geometric shape of a fluid particle trajectory in a regenerative turbomachine with bucket form blades. The fluid particle path was assumed to be a helix wrapped into a torus.

Details

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

Keywords

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Article
Publication date: 1 July 1939

G.N. Patterson

AN interesting feature of modern aeroplane design is the growing use of duct systems. The low drag and heat regeneration obtainable from a cooling duct is now an…

Abstract

AN interesting feature of modern aeroplane design is the growing use of duct systems. The low drag and heat regeneration obtainable from a cooling duct is now an accomplished fact. Ventilation systems for cabin aircraft have been introduced. In the future we may see duct systems used in connexion with the control of the boundary layer. As aeroplane design is improved, new applications of duct systems continue to appear.

Details

Aircraft Engineering and Aerospace Technology, vol. 11 no. 7
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 23 August 2011

Francisco Castro, Teresa Parra, César Quispe and Pilar Castro

The paper aims to focus on airflow and heat transfer inside the human nasal cavity. The contribution of this work is the inertial analysis of the momentum and thermal…

Abstract

Purpose

The paper aims to focus on airflow and heat transfer inside the human nasal cavity. The contribution of this work is the inertial analysis of the momentum and thermal stress of the cavity throughout the respiratory cycle.

Design/methodology/approach

By means of computer tomography scans, an accurate three‐dimensional anatomical representation of the human nasal cavity was obtained. A three‐dimensional numerical model is presented in order to predict the time evolution of flow patterns during a quiet breathing cycle, covering inhalation and exhalation. An inertial analysis of the momentum and a detailed study of the thermal behaviour during the breathing cycle is carried out.

Findings

Head loss, velocity and temperature values are in agreement with experimental results from previous studies. Based on these results, the influence of the inhalation and the exhalation on the flow pattern and air conditioning has been reviewed. Results suggest that the anterior and posterior turbinate regions are where the air conditioning is primarily produced.

Practical implications

The future goal is to investigate respiratory disorders to increase the effectiveness of the eventual treatment of the pathology. The model could be a useful tool to predict, for instance, the modification of the flow patterns due to septal perforations.

Originality/value

The transient resolution provides insight into the momentum and thermal inertia though the breathing which is far from being well understood.

Details

Engineering Computations, vol. 28 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 1 September 1967

Albert N. Debono and Maurice G. Pollard

THE possibility of applying boundary layer control by suction at the trailing edge to reduce the profile drag of a helicopter rotor blade using centrifugal forces to…

Abstract

THE possibility of applying boundary layer control by suction at the trailing edge to reduce the profile drag of a helicopter rotor blade using centrifugal forces to provide the suction was investigated. It was shown theoretically that it is possible to use this method of suction, and that it is advantageous to suck at the trailing edge if the drag reduction obtained was greater than a certain value which depended on the amount of suction. Experimental work was carried out on a model wing with different types of slots to determine the profile drag reduction possible using theoretically predicted suction flow rates. The experiments were carried out at an effective Reynolds Number based on wing chord of 0.62 x 108. It was found that a single long slot of 2 per cent chord width spanning the whole blade, as close as possible to the trailing edge on the upper surface, gave the best results. The maximum drag reduction occurred at high values of lift coefficient and was of the order of 20 per cent. Using the experimental results it was shown that a helicopter employing this type of boundary layer control would require less engine power.

Details

Aircraft Engineering and Aerospace Technology, vol. 39 no. 9
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 February 1969

An exposition of the need of supersonic aircraft to have a variable geometry intake and a fully variable convergent‐divergent nozzle for optimum performance. POWERPLANTS…

Abstract

An exposition of the need of supersonic aircraft to have a variable geometry intake and a fully variable convergent‐divergent nozzle for optimum performance. POWERPLANTS for supersonic aircraft bear only a superficial resemblance to the propulsive units of their subsonic counterparts. A typical subsonic turbojet powerplant consists of a high compression engine with a short fixed intake, and, possibly, a variable convergent nozzle. The supersonic aircraft on the other hand requires a powerplant with a sophisticated variable geometry intake having its own automatic control system and a fully variable convergent‐divergent nozzle in order to extract the full performance throughout the speed range from the slightly lower pressure ratio engine.

Details

Aircraft Engineering and Aerospace Technology, vol. 41 no. 2
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 February 1952

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United…

Abstract

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

Details

Aircraft Engineering and Aerospace Technology, vol. 24 no. 2
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 December 1950

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Techical Memoranda of the United States…

Abstract

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Techical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 12
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 November 1965

C.E. Tharratt

A Theoretical Approach to Assessing the Thermodynamic Process Within the Combustion Chamber of the Propulsive Duct, an Examination of the Potential of the Duct with…

Abstract

A Theoretical Approach to Assessing the Thermodynamic Process Within the Combustion Chamber of the Propulsive Duct, an Examination of the Potential of the Duct with Special Reference to the Application of Feedback and Spark Discharge Techniques. Development of the propulsive duct has been retarded by the absence of a suitable theoretical analysis. This paper, based on four years of experimental investigation by the author, discusses the problems involved and puts forward a theory which closely follows practical results. The theory is then used to examine the potential of the duct and it is shown that by applying feedback and spark‐discharge techniques, a low specific fuel consumption and unlimited thrust, outside the audible range, is theoretically possible. Finally, it is shown that the marriage of the duct to electrical power generated from atomic sources otters attractive possibilities for V.T.O.L. and aircraft propulsion of the future.

Details

Aircraft Engineering and Aerospace Technology, vol. 37 no. 11
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 October 1930

N.A.V. Piercy

IN these articles an attempt will be made to provide an introduction to a large subject specially serviceable to engineers. Restrictions on space make themselves felt in…

Abstract

IN these articles an attempt will be made to provide an introduction to a large subject specially serviceable to engineers. Restrictions on space make themselves felt in various ways. Proper acknowledgments cannot be given for the sources of information beyond mention of the books of Bairstow, Lamb, Cowley and Levy, and Glauert, to which frequent reference has been made. No account can be included of the fascinating and often instructive historical development of the science; it must be assumed that proofs of various essential theorems will be sought in text‐books of Engineering, Mathematics and Physics; lastly, there can occur little opportunity for the working of illustrative examples upon which a proper grip of the subject greatly depends. The engineer of experience will detect much that, with slight generalisation, could be made capable of important use in other branches of his profession, but in this treatment we shall keep closely in view the scientific aspect of aircraft design, structural strength apart.

Details

Aircraft Engineering and Aerospace Technology, vol. 2 no. 10
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 1991

J.R. Carby‐Hall

In a previous monograph a discussion took place on stages one and part of stage two of the three stage process in an unfair dismissal action, namely the employee having to…

Abstract

In a previous monograph a discussion took place on stages one and part of stage two of the three stage process in an unfair dismissal action, namely the employee having to show that he has been dismissed (stage one), and some of the reasons for dismissal which fall within the statutory categories, namely the employee's capability and qualifications; misconduct and redundancy (part of stage two). In this monograph an analysis is proposed on the two remaining reasons, these being the contravention of a duty imposed by an enactment and some other substantial reason. There will then follow a discussion on the test of fairness as constituting the third of the three stage process and on the remedies available when the tribunal finds that the employee has been unfairly dismissed.

Details

Managerial Law, vol. 33 no. 1/2/3
Type: Research Article
ISSN: 0309-0558

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