| Due to the higher luminous efficacy,better color rendering and longer lifetime of the high intensity discharge lamp(HID),it is considered as a novel illumination light sources.But acoustic resonance(AR)occurs in HID lamps operating at high frequency,which results in arc distortion,fluctuation,rotation,flickering and extinction of lamp in the most severe cases.Acoustic resonance phenomenon has become the major obstacle in the application of HID lamps.In recent years,the theoretical and experimental researches of acoustic resonance suppress effectively the acoustic resonance phenomenon,while the AR suppression can't be realized completely.In this thesis,the multi-physics model of HID lamp is established and solved by using COMSOL software.Achieved results are meaningful for the studies on acoustic resonance.Firstly,the structure,working principle,discharge characteristics and related electronic ballast technology of HID lamp are introduced in detail.The characteristics of acoustic resonance phenomena are described and the detection and suppression methods of are also investigated.Secondly,the finite element conception and its applications based on COMSOL software are introduced.By analyzing the multi-physics process of the HID lamp,it can be convinced that the coupling of multiple physical fields,such as electricity,heat and flow,are involved.Furthermore,the multi-physics field model of HID lamp is established with COMSOL software,and the temperature distribution of HID lamp is obtained.Finally,the multi-physics model is applied to the optimization design of HID lamp electrodes.By comparing the achieved result with the experiments,the validity of the model is achieved.Meanwhile,the relationship between the temperature distribution and the structure of the electrodes is analyzed.The simulation results show that the temperature of the electrode increases with the increase of its length.However,the temperature of the electrode drops with the increase of its radius. |
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