Modal Analysis Of Automobile Exhaust Waste Heat Thermoelectric Generation Device

As a pillar industry of national economy, the automotive industry developed rapidly in rencent ten years, and the car ownership of our country is rising year by year, the huge amount of car ownership has brought unprecedented challenges to our country’s energy security. Oil resources is not rich in China, and per capita less, coupled with the rising of international oil prices, new energy vehicles, electric vehicles have not yet the full realization of industrialization, in this context, to take full advantage of the limited energy resources to improve energy using efficiency is extremely important. Using thermoelectric generation technology can retrieve the waste heat of vehicle exhaust, and achieve energy savings, therefore, it is necessary to do some structural research on the thermoelectric generation device which is the key of thermoelectric generation system, so improve the comprehensive performance.In this thesis, mainly doing structure research and vibration characteristics analysis to the thermoelectric generation device from the perspective of the finite element method modal analysis, and based on the results of the analysis, putting a optimization improvement program which aimed at improving the device vibration feature, enabling the device is more reliable, efficient, stable work. First of all, introduce the structural features,unit and working principle of the general thermoelectric generation devices, and a commonly used at home and abroad thermoelectric generation devices.Taking this device as the study object, using the finite element pre-processing software Hypermesh, constructed its finite element model and describing the modeling process in detail. To bring a reasonable modeling assumptions, and simplify the structure of the device, select the appropriate position to impose the constraint boundary conditions. Secondly, using ABAQUS/Standard solver module of the ABAQUS software to make the finite element model for modal analysis, achieving the natural frequency and mode shapes of the device and its major components,describing the mode shapes.the modal analysis results show that:under the overall constraint state, the natural frequency of the device perfectly avoiding the engine excitation frequency range, it is no dangerous about the occurs of resonance phenomenon, and depend on the overall mode shapes and resonance stress cloud picture to modify some areas of the device. In addition, under the constraint state, the first-order non-zero value modal of the cooling water channel and the exhaust channel is small, it is no completely avoiding the excitation frequency of the engine, there has the possibility of resonance. Finally, based on the calculated results of modal analysis, to optimize the exhaust channel and the cooling water channel of the device, doing constrained modal analysis for improved models,comparing the analysis results with the results of no improved structure before, the results show that the natural frequency of the improved model was significantly increased, perfectly avoiding the engine excitation frequency range,does not occur the dangerous phenomenon of resonance,and the improved model has a good vibration characteristics.In short, this thesis using the finite element method modal analysis to do some some structural research on the thermoelectric generation device, exploring and realizing the structural analysis and improvement of the vehicle exhaust waste heat thermoelectric generation device, the comprehensive performance, especially vibration characteristics of the device have significantly improved.The results of modal analysis also provides the device a basis for further structural optimization.