195 results found
Bayley FJ, Childs PRN, 1994, Air temperature rises in compressor and turbine stator wells, American Society of Mechanical Engineers (Paper), Pages: 1-10, ISSN: 0402-1215
This paper considers the fluid dynamic principles determining the consequences of mainstream fluid ingressing to the comparatively shallow space between the rotor disc and the ring used in many designs of axial-flow turbo-machine, especially compressors, to support the stator blades at their inner ends. Windage power due to friction between this fluid and the bounding walls of this annular space, or 'stator well', can lead to substantial temperature rises in this region. The feasible range of flow regimes is first developed, especially as influenced by leakage through the internal seals beneath the stators separating adjacent wells. Using published data, on windage coefficients and the effects of geometry on the flow through the wells, very little of which has been obtained from truly representative flow conditions or geometries, calculations have been made to estimate the likely rises in temperature to be anticipated in realistic well designs. Leakage rates appear, not unexpectedly, to be crucial in determining these temperature rises, but the geometries of the system are little less critical, in particular the ratio of the outer to inner radiuses of the stator well and the outer peripheral clearances between rotor and stator surfaces. Leakage into a well from its adjacent neighbour is shown to lead to higher temperature rises downstream of the labyrinth seal and the possible effects of recirculation through stator wells from the mainstream boundary layer could be significant.
CHILDS PRN, TURNER AB, 1994, HEAT TRANSFER ON THE SURFACE OF A CYLINDER ROTATING IN AN ANNULUS AT HIGH AXIAL AND ROTATIONAL REYNOLDS NUMBERS, 10th International Heat Transfer Conference, Publisher: INST CHEMICAL ENGINEERS, Pages: 13-18
Childs PRN, Rayner D, Turner AB, 1992, Heat transfer to a cylindrical drum rotating in an annulus under a single stator blade row, International Centre for Heat and Mass Transfer, International Symposium, Heat Transfer in Turbomachinery
Childs PRN, Turner AB, Vaughan CM, et al., 1992, Heat transfer to a rotating drum in an annulus with a stator blade row and axial throughflow. ASME Paper 92-GT-249, ASME Turbo Expo 1992, Publisher: ASME
Rayner D, Vaughan CM, Childs PRN, et al., 1992, Numerical solution of the heat transfer in turbulent, swirling annular flows, Pages: 511-531
A numerical investigation into the heat transfer from a heated inner cylinder, rotating in an annulus with an axial throughflow of air, is presented. The finite difference solution algorithm incorporates the advantages of the SIMPLEC pressure-correction scheme with a Full Approximation Scheme (FAS) multigrid method. The increased efficiency allows a thorough numerical investigation to be undertaken.
Childs PRN, 1991, Heat Transfer at the surface of a cylinder rotating in an annulus with a stator blade row and axial throughflow
Baxter W, Aurisicchio M, Mugge R, et al., Decontaminating experiences with circular offerings, Product Lifetimes and The Environment (PLATE) 2017
Baxter W, Aurisicchio M, Mugge R, et al., Positive and negative contamination in user interactions, ICED17: 21st International Conference on Engineering Design, Publisher: Design Society
The purpose of this paper is to present contaminated interaction as a design construct. Interactions with an object can be altered,positively, neutrallyor negatively,due to some prior use. In such cases, the interaction departs from the designed condition and is said to be contaminated. This is particularly significant as objects, physical or non-physical, have multiple uses or are shared amongst users. We propose an ontological model of contaminated interaction based on a review of literature and an analysis of user experiences. The model outlines the process of contaminated interaction including the drivers and outcomes. In a negative context, contamination can lead to consumers misusing, negatively experiencing, or avoiding the object altogether. Positive contamination sees the opposite effect in which usability can increase, users report more positive experiences and users seek out or cherish the object. Together, this model presents an approach to understanding and addressing contamination in the design process to enable the creation and maintenance of meaningful experiences.
Childs PRN, Holloway M, Julia M, Folding mechanism for a remotely deployable robotic vehicle, International Symposium on Robotics
An innovative design for a folding robotic vehicle is presented that can deploy through small openings into crawl spaces and underfloor voids to survey and carry out operations within them. The mechanism employs a four bar linkage, enabling the axles to be extended away from the chassis and the axle to be deployed in line with the chassis, thus producing an elongated but small cross sectional area. In its low cross-sectional area form the device can be fed in through a small opening and once in position, the axles can be rotated into their functional position and locked in place. To remove the robot the mechanism works in reverse, with the axle is unlocked and rotated in line with the chassis This transformation is a key enabler for deployment and practical applications of this type of robot. The mechanism has been commercially developed and used for both survey and applying treatments in a wide range of building applications, although other uses are possible. This paper describes the practical aspects of the mechanism as an enabler for the transformation of a robot chassis for accessing confined spaces.
Childs PRN, Holloway M, Julia M, A robot for spray applied insulation in underfloor voids, 47th International Symposium on Robotics
This paper focuses on the application of robotics in a new field for applying surface treatments in building voids and thedevelopment of the architecture of the robotic vehicle for use in this application. The nature of the application means thatthe robotic vehicle must be capable of accessing voids through small openings and this has led to a deployable architecturefor the vehicle which can be fed through an opening and then reconfigures its form to enable practical operation. A typicalapplication for the robot is to apply thermal insulation to the underside of wooden or concrete floors in buildings. Theterrain is varied ranging from sand to impacted dusty hard core, can be strewn with builders’ debris such as bricks andtimber, and is interspersed with retainer walls that support the floor above. Within this environment the robot needs to beable to navigate and deploy a spray applied insulation fed by a hose assembly. This paper describes the robot architectureand its development with particular focus on deployable features enabling access to confined spaces, the traction systemused to negotiate diverse surfaces while pulling the umbilical hose assembly, the sensor array and how it is used to controlthe spray patterns. The resulting robots have been commercially developed, and are successfully spraying thermal insulationin a wide range of building applications.
Childs PRN, Julia M, Holloway M, et al., Autonomous Surveying of Underfloor Voids, 47th International Symposium on Robotics
In this paper, a novel robotic system that solves the problem of autonomous mapping an underfloor void is presented. The approach is based on a 3D laser scanner. A real time navigation system and a new high level planner that selects the next best scanning position controls the motion of the robot. Multiple scans are aligned using ICP and graph optimization techniques. Finally, a point cloud fusion algorithm creates a global model of the environment from the aligned scans. The survey robot has been successfully deployed in a commercial application for scanning underfloor voids before and after the application of thermal insulation. Using this system, the robot was successfully able to autonomously map the controlled test scenario. For some applications the quantity of rubble within the void caused the real time navigation to fail and teleoperation and manual initialization of the ICP algorithm was necessary.
Childs PRN, Michalakoudis I, Harding J, Using functional analysis diagrams for production cost optimization, IEEE-ICAMSE 2016
This paper presents a methodology combining Failure Modeand Effects Analysis (FMEA) and Value Engineering (VE),assisted by a set of hierarchical Functional Analysis Diagram(FAD) models, and its pilot introduction in a UK-basedmanufacturing Small Medium Enterprise (SME). Theproposed methodology suggests the parallel execution of bothprocesses, using a combination of FAD models and the FMEAtabular tool to yield results for both FMEA and VE. Theresulting Risk Priority Number (RPN) is used to identify andprioritize not only the high-risk components requiringimprovements (highest RPN values), but also the potentiallysuperfluous components (lowest RPN values) that could besafely downgraded to reduce unnecessary costs.
Garvey B, Childs P, DESIGN AS AN UNSTRUCTURED PROBLEM: NEW METHODS TO HELP REDUCE UNCERTAINTY – A PRACTITIONER PERSPECTIVE in Impact of Design Research in Industrial Practice Eds A Chakrabarti and U Lindemann Springer 2016, Impact of Design Research on Industrial Practice
Lee S, Jiang P, Childs P, et al., Functional Analysis Diagrams with the representation of movement transitions, ASME 2013 International Mechanical Engineering Congress and Exposition, IMECE 2013
A study on utilising a graphical interface to representmovement transmission within products has been conducted tosupport a creative conceptual design process that separates theconsideration of functional requirements and motionrequirements. In engineering design, many representations ofproduct structure have been proposed to assist in understandinghow a design is constituted. However, most of theserepresentations demonstrate only functions and are not able todemonstrate design structure. Functional Analysis Diagrams(FAD) provides a solution for this. An FAD shows not onlyfunctions but also physical elements by the network of blocksand arrows and thus it is capable of demonstrating varioustypes of information and the design scheme. This characteristicgives FADs an advantage for designers to combine differenttypes of information including useful and harmful interactionsto gain an overview of the design task. This study focuses onusing circles instead of arrows to represent movement attributesof mechanisms and machine elements in a KinematicFunctional Analysis Diagram (KFAD) and explores methods ofutilising it in mechanical design. A commercial case study ofmedical equipment design conducted with the assistance ofKFADs and a component database, mechanism and machineelements taxonomy (MMET), is described to illustrate theprocess. The design outcome shows that it is feasible to followthe proposed conceptual design process. With the help ofKFADs and the machine elements taxonomy to enableconsideration of movements, diverse considerations and designsolutions are possible.
Sikhwal RK, Childs PRN, Innovation toolkit for identification of the optimal module options in open platform architecture products, NordDesign 2018, Publisher: Design Society
Open platform architecture products (OPAP) are the keyenablers for Product designfor Mass Individualisation.Itis a new product design paradigm that comprises an open hardware platform, mass-producedby large manufacturersand multiple independent modules,invented and produced by other smaller companies and by the end-userthat are integratedwith the platform. It gives freedom to end-usersto integrate different modules into the platform as per their choice. This type of product integration will be engaged with by the all actors involved in the design and aims to help them to be more creative and innovative. The end product will be highly individualised and technologically advanced.Based on explorative literature analysis, with practical insights from an industrial questionnaire survey, anInnovation toolkitfor the end-userhas beendeveloped.TheInnovation toolkitprovides a mean of selecting an optimal module option for each module which will be integrated onthe hardware platform. The design of theInnovation toolkitfor OPAP has been approachedin three different steps: Modelling of OPAP, Modelling of evaluation measures and evaluation indices with end-userpreferences and Identification of the optimal module options. In this work, variations in module options for a given module are modelledby an AND-OR tree and parameters of the nodes in this tree. Different module options for the selected module are evaluated by various evaluation measures. These evaluation measures are convertedinto comparable customer satisfaction indices. The optimal OPAP is identifiedby constrained optimisationof the overall customer satisfaction index. Twocase studieshavebeen presented to demonstrate theeffectiveness of the introduced Innovation toolkit.These case studies illustrate that the Innovation toolkit can readily be appliedto these typesof product developmentto obtain a highly individualised OPAP with optimised mo
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