Imperial College London

ProfessorPeterChilds

Faculty of EngineeringDyson School of Design Engineering

Head of the School of Design Engineering
 
 
 
//

Contact

 

+44 (0)20 7594 7049p.childs Website CV

 
 
//

Location

 

Studio 1, Dyson BuildingDyson BuildingSouth Kensington Campus

//

Summary

 

Publications

Publication Type
Year
to

200 results found

Robb DA, Flora H, Childs PRN, 2010, Sketching to solid modelling skills for mechanical engineers, 11th International Conference on Engineering and Product Design Education, Publisher: The Design Society, Pages: 275-280

CONFERENCE PAPER

Childs PRN, Tsai SK, 2010, Creativity in the design process in the turbomachinery industry, J. of Design Research, Vol: 8, Pages: 145-145, ISSN: 1748-3050

JOURNAL ARTICLE

Childs PRN, McGlashan NR, Heyes AL, 2010, Accessing high thermal efficiency power generation using fluid phase chemical looping. 2010-ISJPPE-0001, 3rd International Symposium on Jet Propulsion and Power Engineering

In order to burn a hydrocarbon fuel efficiently using conventional cycles, very high temperatures are required. Chemical looping combustion offers an alternative cycle for large scale power production. In chemical looping combustion a carrier molecule is used to transport oxygen between two redox reactions, one where the carrier is oxidised and another where it is reduced by reaction with a fuel. Separation of the oxygen carrier from fuel ash can be aided by means of phase difference and this is a key advantage of fluid phase chemical looping combustion where the carrier medium proposed is sodium, potassium or zinc. The principle exploited in fluid phase chemical looping combustion is the recirculation of both energy and entropy. High thermal efficiencies, circa 75% at 35 bar are theoretically achievable taking into account component efficiencies, with separation of nitrogen and carbon dioxide, in combination with the water shift gas reaction, as an inherent part of the cycle if air is used as the oxygen source.

CONFERENCE PAPER

Regan N, Peng Z, Atkins NR, Long CA, Childs PRNet al., 2010, An investigation to oil spray characteristics under cross flow environment of internal air system. 2010-ISJPPE-3016, 3rd International Symposium on Jet Propulsion and Power Engineering

For investigating the oil spray characteristics in internal air systems of gas turbine engines, a test rig has been built for simulating the oil leaking jet flow when a fracture takes place on those high flowrate oil supply pipes. With the air flow velocity of cross flow up to 200 m/s, oil sprays with the injection pressure up to 7 bar were provided by an purpose-built injection system. Various injector orifices with different shapes and dimensions were prepared for considering different fracture situation though only one circular nozzle was examined in the current study. While Laser Imaging was used for examining the jet behaviour and flow field with interaction between the oil spray and the cross flow, Phase Doppler Anemometry (PDA) was employed for measuring the size and velocity distributions of oil droplets. Measurements through different planes of the spray were conducted for exploring the droplet break-up and oil-air mixing process. Results showed that the high velocity of cross flow made significant enhancement for both the jet break-up and droplet break-up, in particular those droplets with bigger size, while the momentum flux ratio has very unapparent influence on variation of droplet size distributions. With the penetration of the oil spray, velocity differences between the cross flow and droplets gradually become smaller and this tends to reduce the further droplet break-up at the downstream area. Meanwhile, relevant data also demonstrated that the evaporation of different size droplets was accelerated with high velocity cross flows.

CONFERENCE PAPER

Childs PRN, McGlashan NR, Heyes AL, 2010, Power generation with fluid phase chemical looping combustion ETN 2010-068, 5th International Gas Turbine Conference

A new type of power cycle for large scale generation has been developed based on chemical looping that has theoretically been shown to offer practical thermal efficiencies of between 72% and 82%. Instead of performing hydrocarbon combustion in a single reaction, as in conventional power plant, the hydrocarbon is oxidised using two reactions. An additional species is required, typically a metal, which re-circulates between the two reactions carrying oxygen atoms. The chemical looping technology concerned uses processes comparable to those in the human body for extraction of energy from food but instead of using haemoglobin, metal vapour is used as the carrier for the oxidation and reduction processes. The cycle avoids the large entropy changes associated with Carnot-cycle based engines and high thermal efficiencies are possible with inherent carbon capture for power generation plants. The technology represents a step change in power generation although a series of technical barriers remain for its implementation including equation of state data, detailed chemical kinetics, development of practicable schemes to duct the highly reactive fluid flows and determination of slag melt thermodynamics. This paper explores the cycle development and technology requirements as well as addressing the need to consider cycle variants in power generation.

CONFERENCE PAPER

Childs PRN, 2010, Ethics, Assessing creativity in design: emerging themes for engineering, Editors: Ball, ISBN: 978-1-904804-83-3

BOOK CHAPTER

Childs PRN, 2010, People Metrics, Assessing creativity in design: emerging themes for engineering, Editors: Ball, Publisher: Higher Education Academy Engineering Subject Centre, ISBN: 9781904804833

BOOK CHAPTER

Robb DA, Childs PRN, Flora H, 2009, Sketching to solid modelling skills for mechanical engineers, Pages: 275-280

Hand sketching skills remain an important part of aiding discussions in meetings and are, for example, an essential asset for brainstorming and other ideation activities. The tendency for novice students on entry to engineering and design degree programmes to produce naïve, laboured or'glitzy'sketches and inappropriate CAD representations has previously been identified. This paper describes the strategy implemented at Imperial College London for the MEng in Mechanical Engineering in order to develop key sketching skills across the diverse intake of students and in conjunction with the development of CAD solid modelling and technical drawing capabilities. The approach, based on use of visual diaries, museum and site visits, design, make and test and conceptual exercises has ensured that all students are able to sketch and produce solid models in their first year, although the production of naïve and laboured sketches continues to some extent.

CONFERENCE PAPER

Hall A, Childs P, 2009, Innovation design engineering: Non-linear progressive education for diverse intakes, Pages: 312-317

This paper discusses the non-linear progressive educational techniques developed and adopted by the Innovation Design Engineering (IDE) masters degree at the Royal College of Art and Imperial College, London. In particular a focus is applied to the development of creative processes for diverse intakes without recourse to overt systems presentation. Innovation design engineering is viewed as a cutting-edge product design, experimentation and enterprise discipline with applicants drawn from three areas including engineering, industrial design and other art, design and business disciplines. The co-education of such a diverse intake requires careful balancing of an academic programme to ensure that all parties are stimulated and enabled to expand their knowledge and skills base while also contributing to a communal environment via team-based activities. Designers work at the centre of complex, demanding projects, juggling creatively in teams, to generate great ideas, designs and successful products. In order to achieve such goals it is critical for students to attain high levels of selfreflection, social networking, work-collaboration and interdisciplinarity. This is achieved by surrounding the students with experts and leaders in their fields to support them in their design ventures. Through reflection and theorising, a conceptual base for educating innovative design engineers is explored. One of the techniques described provided evidence to suggest running a design enterprise strand in the programme, a proposal that has now been implemented. Students elect from three learning strands: experimental design; design for manufacture; and design enterprise. The design enterprise strand addresses product, idea and service launching, finance, marketing, commercialisation, designing service support infrastructures and establishing production and supplier relationships. Design for manufacture is the traditional core industrial design activity associated with advanced manufactur

CONFERENCE PAPER

Adams DJ, Beniston LJ, Childs PRN, 2009, Promoting creativity and innovation in biotechnology, TRENDS IN BIOTECHNOLOGY, Vol: 27, Pages: 445-447, ISSN: 0167-7799

JOURNAL ARTICLE

Coren D, Childs PRN, Long CA, 2009, Windage sources in smooth-walled rotating disc systems, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, Vol: 223, Pages: 873-888, ISSN: 0954-4062

JOURNAL ARTICLE

Childs PRN, 2009, Labyrinth Seal Flow, Publisher: ESDU, ISBN: 978 1 86246 639 5

BOOK

Patounas DS, Long CA, Childs PRN, 2009, DISC HEAT TRANSFER IN GAS TURBINE COMPRESSORINTERNAL AIR SYSTEMS, 8th European Conference on Turbomachinery, Pages: 377-386

Experimental disc heat transfer measurements were obtained from the internal air systemin high-pressure compressor cavities of gas turbine engines with axial throughflow using a rigbased on real aero-engine components. Tests were carried out over a range of non-dimensionalparameters representative of real engine conditions (Re up to 10000000 and Rez up to 110000).The heat transfer data were obtained from surface temperature measurements through a2D tapered disc numerical solution. Local values of heat transfer coefficient and Nusseltnumber showed a decreasing distribution with radius close to turbulent natural convection,similar to those found in past research. Study of the average Nusselt number showed that thisincreases with increasing axial Reynolds number and decreases with increasing rotationalReynolds number. These are consistent with increased action of the throughflow inside thecavity and an increase in the Coriolis force attenuating the flow inside the cavity.

CONFERENCE PAPER

Cooke A, Childs P, Sayma N, Long CAet al., 2009, A disc to air heat flux error and uncertainty analysis applied to a turbomachinery test rig design, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, Vol: 223, Pages: 659-674, ISSN: 0954-4062

JOURNAL ARTICLE

Regan NJ, Atkins NR, Long CA, Childs PRN, Hutcheson PS, Hart KJet al., 2009, AN EXPERIMENTAL STUDY OF SPRAYS IN CROSS FLOW REPRESENTATIVE OF GAS TURBINE ENGINE SECONDARY AIR SYSTEMS, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 133-143

CONFERENCE PAPER

McGlashan NR, Childs PRN, Heyes AL, Marquis AJet al., 2009, PRODUCING HYDROGEN AND POWER USING CHEMICAL LOOPING COMBUSTION AND WATER-GAS SHIFT, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 177-188

CONFERENCE PAPER

Farahani A, Childs P, 2009, VALIDATION AND COMPARISON OF STRIP SEAL DESIGNS FOR GAS TURBINE ENGINE NOZZLE GUIDE VANES, ASME International Mechanical Engineering Congress and Exposition, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1185-1192

CONFERENCE PAPER

Tsai SK, Childs PRN, 2009, TRIZ Incorporating the BRIGHT Process in Design, TRIZ Journal

The theory of inventive problem solving (TRIZ) is widely acclaimed by adoptees and in the academic literature. An apparent disparity exists, however, between the low reported industrial take-up of TRIZ and perceptions in the TRIZ community which indicate more widespread use. A review of TRIZ, design processes and creative problem solving processes are reported, showing differences in the emphasis on creative thinking and the use of iteration. The advantages of a procedure related to the aspects of usability, creative thinking and iteration within the TRIZ environment has been recognised and addressed by the development of a new process named BRIGHT.

JOURNAL ARTICLE

Hounsham S, Stobart R, Cooke A, Childs Pet al., 2008, Energy recovery systems for engines, SAE Technical Papers

Energy recovery from IC engines has proved to be of considerable interest across the range of vehicle applications. The motivation is substantial fuel economy gain that can be achieved with a minimal affect on the "host" technology of the vehicle. This paper reviews the initial results of a research project whose objective has been to identify system concepts and control methods for thermal recovery techniques. A vapour power cycle is the means of energy transfer. The architecture of the system is considered along with support of the fuel economy claims with the results of some hybrid vehicle modelling. An overview of the latest experimental equipment and design of the heat exchanger is presented. The choice of control architecture and strategy, whose goal is overall efficiency of the engine system, is presented and discussed. Some initial control results are presented. One important project aim is to identify and implement an optimal control method that allows an explicit balance, between the IC engine output and the recovered work from the vapour power cycle. Initial simulation work shows that there are significant, potential, fuel economy advantages, between 6% and 31%, and that high efficiencies can be achieved at practical operating pressures. Conclusions point to the need to investigate and develop the system control dynamics. Copyright © 2008 SAE International.

JOURNAL ARTICLE

Tsai SK, Childs PRN, 2008, TRIZ incorporating the BRIGHT process in design, 8th ETRIA World TRIZ Future Conference

CONFERENCE PAPER

Farahani A, Childs PRN, 2008, Validation and comparison of strip seal designs for gas turbine engine nozzle guide vanes, IMECE2008, ASME International Mechanical Engineering Congress and Exposition, Publisher: ASME

CONFERENCE PAPER

Hounsam S, Stobart RK, Cooke AO, Childs PRNet al., 2008, Energy Recovery Systems for Engines. SAE Paper 2008-01-0309, SAE World Congress 2008

Energy recovery from IC engines has proved to be ofconsiderable interest across the range of vehicleapplications. The motivation is substantial fuel economygain that can be achieved with a minimal affect on the“host” technology of the vehicle.This paper reviews the initial results of a research projectwhose objective has been to identify system conceptsand control methods for thermal recovery techniques. Avapour power cycle is the means of energy transfer. Thearchitecture of the system is considered along withsupport of the fuel economy claims with the results ofsome hybrid vehicle modelling. An overview of the latestexperimental equipment and design of the heatexchanger is presented. The choice of controlarchitecture and strategy, whose goal is overall efficiencyof the engine system, is presented and discussed. Someinitial control results are presented. One importantproject aim is to identify and implement an optimalcontrol method that allows an explicit balance, betweenthe IC engine output and the recovered work from thevapour power cycle.Initial simulation work shows that there are significant,potential, fuel economy advantages, between 6% and31%, and that high efficiencies can be achieved atpractical operating pressures. Conclusions point to theneed to investigate and develop the system controldynamics.

CONFERENCE PAPER

Long CA, Childs PRN, 2007, Shroud heat transfer measurements inside a heated multiple rotating cavity with axial throughflow, 5th Conference on Turbulence, Heat and Mass Transfer, Publisher: ELSEVIER SCIENCE INC, Pages: 1405-1417, ISSN: 0142-727X

CONFERENCE PAPER

Long CA, Childs PRN, 2007, Shroud heat transfer measurements inside a heated multiple rotating cavity with axial throughflow, International Journal of Heat and Fluid Flow, Vol: 28, Pages: 1405-1417, ISSN: 0142-727X

Experimental measurements of heat transfer are made from the inner peripheral surface of a rotating test rig designed to be similar to a gas turbine high pressure compressor internal air system. The test rig comprises a number of annular discs sealed at their periphery by a shroud. An axial throughflow of cooling air enters the test rig and flows through the annular section between the disc bores and a central shaft. Tests were carried out for the following range of rotational speeds and axial throughflow rates: 540 < NR< 10,800 rev/min and 0.124 < over(m, ̇) < 0.85 kg / s (corresponding to the range of rotational and axial Reynolds numbers 4 × 105< Reφ{symbol}< 7.7 × 106and 3.3 × 104< Rez< 2.2 × 105). The shroud Nusselt numbers are found to depend on the shroud Grashof number. They are relatively insensitive to changes in axial Reynolds number and two geometrically similar cavities give similar values of Nusselt number. The heat transfer from the shroud is governed by the mechanism of free convection. It is recommended that a modified form of a correlation for Rayleigh-Bénard convection in a gravitational force field be used, with appropriate modification, to predict shroud heat transfer. © 2007 Elsevier Inc. All rights reserved.

JOURNAL ARTICLE

Long CA, Miche NDD, Childs PRN, 2007, Flow measurements inside a heated multiple rotating cavity with axial throughflow, 5th Conference on Turbulence, Heat and Mass Transfer, Publisher: ELSEVIER SCIENCE INC, Pages: 1391-1404, ISSN: 0142-727X

CONFERENCE PAPER

Long CA, Miche NDD, Childs PRN, 2007, Flow measurements inside a heated multiple rotating cavity with axial throughflow, International Journal of Heat and Fluid Flow, Vol: 28, Pages: 1391-1404

This paper discusses experimental results from a multiple cavity test rig representative of a high pressure compressor internal air system. Measurements of the axial, tangential and radial velocity components are presented. These were made using a two component, laser doppler anemometry (LDA) system for a range of non-dimensional parameters representative of engine conditions (Re up to 4 × 106 and Rez up to 1.8 × 105). Tests were carried out for two different sizes of annular gap between the (non-rotating) drive shaft and the disc bores. The axial and radial velocities inside the cavities are virtually zero. The size of the annular gap between disc bore and shaft has a significant effect on the radial distribution of tangential velocity. For the narrow annular gap (dh/b = 0.092), there is an increase of non-dimensional tangential velocity V/Ωr with radial location from V/Ωr < 1 at the lower radii to solid body rotation V/Ωr = 1 further into the cavity. For the wider annular gap (dh/b = 0.164), there is a decrease from V/Ωr > 1 at the lower radii to solid body rotation further into the cavity. An analysis of the frequency spectrum obtained from the tangential velocity measurements is consistent with a flow structure in the r– plane consisting of pairs of contra rotating vortices.

JOURNAL ARTICLE

Peng Z, New P, Long CA, Childs PRNet al., 2007, Operating characteristics of a high radius pre-swirl cooling system, Hangkong Dongli Xuebao/Journal of Aerospace Power, Vol: 22, Pages: 849-858, ISSN: 1000-8055

An experimental investigation into pre-swirl effectiveness and receiver hole discharge coefficient characteristics for a high radius injection pre-swirl cooling systems was carried out on a physically representative experimental rig with a 450 mm diameter rotor. The receiver holes and pre-swirl nozzle were located at a radius of 181 mm and 180 mm respectively. The experimental work was mainly conducted at 5000-12000 r/min, 4 bar absolute pressure and 1.132 kg/s air supply. The maximum air supply temperature was 190°C. Pressure and temperature distributions in the pre-swirl system were examined with an emphasis on the velocity effectiveness of the pre-swirl system as a whole and on the discharge coefficients of the rotating 'receiver holes' in the rotor. The results showed that the velocity effectiveness increased with increasing swirl ratio resulting in reduced blade cooling flow temperature. Different seal flow configurations caused very different effectiveness at different speeds, but outflow through the inner and outer seals always gave the highest effectiveness compared other configurations. Increasing the seal flow rate reduced the effectiveness. For the coefficient of discharge, except for the low speed range, it increased with increase in swirl ratio for most speeds.

JOURNAL ARTICLE

Long C, Childs P, 2007, The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow, Hangkong Dongli Xuebao/Journal of Aerospace Power, Vol: 22, Pages: 683-693, ISSN: 1000-8055

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig. Measurements of heat transfer from the discs and tangential velocities are presented. The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine. Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air. Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows (Reφ up to 5 × 106 and Rez up to 2 × 105). Two different builds have been tested. The most significant difference between these two build configurations is the size of the annular gap between the (non-rotating) drive shaft and the bores of the discs. The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method. The velocity measurements were made using a two component, LDA system. The heat transfer results from the discs show differences between the two builds. This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity. There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig. For the narrow annular gap, there is an increase of non-dimensional tangential velocity Vφ/Ωr with radial location to solid body rotation Vφ/Ωr=1. For the wider annular gap, the non-dimensional velocities show a decrease with radial location to solid body rotation.

JOURNAL ARTICLE

Morris R, Childs P, Hamilton T, 2007, Sustainability by design: a reflection on the suitability of pedagogic practice in design and engineering courses in the teaching of sustainable design, European Journal of Engineering Education, Vol: 32, Pages: 135-142, ISSN: 0304-3797

JOURNAL ARTICLE

Childs PRN, Hamilton T, Morris RD, Johnston Get al., 2007, Centre For Technology Enabled Creativity, the 8th International Conference on Engineering and Product Design Education, Publisher: The Design Society, Pages: 367-372

CONFERENCE PAPER

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: id=00452804&limit=30&person=true&page=4&respub-action=search.html