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Modelling plasmas for light generation - Some thoughts on the needs of the lighting industry. COST Model Inventory Workshop 12 to 15 April 2005 University of Madeira, Funchal Stuart Mucklejohn UK National Representative to COST529
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Modelling plasmas for light generation - Some thoughts on the needs of the lighting industry COST Model Inventory Workshop 12 to 15 April 2005 University of Madeira, Funchal Stuart Mucklejohn UK National Representative to COST529 GE Consumer & Industrial- Lighting, Melton Road, Leicester LE4 7PD, UK COST529_April05.ppt
What are models used for ? New product development Product improvement Fault finding Production processes Education Training COST529_April05.ppt
What is a lamp ? Light generating component of a system used to illuminate things Within the European Union: An energy using product (EUP) A product subject to the WEEE directive A product subject to the RoHS regulations COST529_April05.ppt
What is a high intensity discharge (HID) lamp ? A light emitting high temperature chemical reactor Characteristics: Plasma has electron temperature = gas temperature Operating pressure 1 to 50 atm, up to 200 atm for UHP Local thermodynamic equilibrium is a reasonable assumption COST529_April05.ppt
Uses of HID lamps Road lighting Car headlamps Stage/studio lighting Horticulture – greenhouse lighting Interior lighting – warehouses & shopping malls Floodlighting – sports & architectural Projection systems COST529_April05.ppt
Types of HID lamps DescriptionTypical application Low-pressure sodium road lighting High-pressure sodium road lighting High-pressure mercury road lighting Metal halide with silica arctube interior, sports, malls Metal halide with ceramic arctube interior, malls, streets Ultra high pressure projection systems COST529_April05.ppt
Some characteristics of HID lamps Power range 20 to 20 kW Output 1600 to 2000000 lumens Life 500 to 28000 h Size 50 to 500 mm Global market >500x106 € per annum COST529_April05.ppt
The system includes light source & the receptor COST529_April05.ppt
Components of HID lamps Outer enclosure - glass outer jacket & metal connectors Arctube - silica or ceramic Electrodes - tungsten Leadwires – molybdenum, niobium Chemical additives - mercury, sodium, metal halides Gas fill - argon, krypton85 Joins Seals COST529_April05.ppt
A metal halide lamp with ceramic arctube COST529_April05.ppt
Interactions within HID arctubes Gas phase 1000 to 6000 K light generation Liquid – Gas 700 to 1300 K dose evaporation Solid – Gas 700 to 1500 K corrosion Liquid – Solid 700 to 1300 K corrosion Solid – Solid 700 to 1500 K corrosion COST529_April05.ppt
Temporal phenomena Steady state Transient Non-LTE Reaction kinetics COST529_April05.ppt
Energy balance for a metal halide lamp From Philips Lighting & the ALITE program COST529_April05.ppt
Life cycle of HID lamps Assumes life of 10000 h Production Raw materials, processes, testing 0 to 100 h Rapidly changing properties to 100 h 100 to 1000 h Significant changes in output 1000 to 10000 h Slowly changing output, failures End of life Disposal Recycling Environmental impact COST529_April05.ppt
Fundamental data Radiation properties of optically thick radiators (line broadening, transitions probabilities) Radiation properties of optically thin radiators (reduced emission coefficients) Diffusion coefficients & mobilities of plasma species Viscosities of buffer gases Thermochemical parameters for: plasma species (discharge properties) liquid - gas reactions (dose chemistry) solid - gas reactions (corrosion) solid - liquid reactions (corrosion) Kinetic parameters for material transport mechanisms COST529_April05.ppt
Examples of predictive models needed Lamp voltage rise through life Lamp voltage & colour changes for vertical & horizontal operation Luminous efficacy through life Output from 200 to 3000 nm Lamp life COST529_April05.ppt
History Many descriptions of models at conferences Large number of scientific publications Valuable resource for the lighting industry But …….. Some reports/papers very difficult to find Software no longer available & not designed for operation by third parties COST529_April05.ppt
Many thanks to: Barry Preston (GE Lighting) Raghu Ramaiah (GE Lighting) Acknowledgements COST529_April05.ppt