【作者】 何鹏；

【导师】 刘占生；

【作者基本信息】 哈尔滨工业大学 ， 动力机械及工程， 2013， 博士

【摘要】 拉杆转子是重型发电用燃气轮机和航空发动机常用的转子结构形式。在我国燃气轮机技术自主化的过程中，具有非连续结构特点和复杂温度分布的拉杆转子动力学特性是燃气轮机技术的关键内容之一。本文以拉杆转子为对象，研究粗糙表面的弹塑性接触特性，提出具有温度分布的转子建模及动力学分析方法。研究了考虑轮盘间弹塑性接触的拉杆转子动力学特性，分析了轴向温度分布对拉杆转子动力学特性的影响，研究了周向不均匀温度分布引起的拉杆转子热弯曲变形及其在快速起动阶段的振动特性，为燃气轮机拉杆转子动力学设计分析提供研究方法和理论参考。主要研究内容包括：针对拉杆转子轮盘间的接触问题，采用有限元方法分析了微凸体弹塑性接触特性，给出了适用范围更大的微凸体弹塑性接触模型，结合粗糙表面统计特性，建立了粗糙表面弹塑性接触模型，进而分析粗糙表面的弹塑性接触特性。提出了表面形貌塑性指数和材料属性塑性指数，分别研究了表面粗糙度和材料属性参数对粗糙表面弹塑性接触面积和接触载荷的影响规律。研究结果可以为粗糙表面弹塑性设计分析提供理论参考。为了分析轴向温度分布对转子动力学特性的影响，基于传统梁单元和单元内部参数变化规律的多项式表达式，建立了考虑轴向变参数的梁单元。采用此模型建立锥形转子有限元模型，分析了锥形参数对转子临界转速和振型的影响规律。结合材料杨氏模量随温度的变化规律，建立了具有轴向温度分布的转子有限元模型，分析了轴向温度分布对转子动力学特性的影响。提出的单元模型可以为具有轴向变参数的转子动力学特性分析提供新的研究方法。针对燃气轮机转子热弯曲问题，采用有限差分法分析了转子横截面温度分布，根据变形等效原理，建立了转子横截面温度分布的等效热弯矩，分析了不同周向温差的轴向分布形式下转子的热弯曲变形。通过仿真计算了热弯曲转子在快速起动过程中的振动特性，分析了热弯曲和不平衡组合下的复杂振动现象。研究了快速起动结束后转子热弯曲衰减过程中转子振幅的变化规律。研究结果可以为燃气轮机快速热起动阶段振动特性分析和诊断提供理论依据。基于粗糙表面弹塑性接触模型，分析了拉杆转子轮盘间弹塑性接触刚度，建立了考虑弹塑性接触的拉杆转子动力学模型，研究了拉杆转子动力学特性及影响因素。结合转子轴向温度，分别研究了轴向温度分布引起的热膨胀和材料属性变化对拉杆转子临界转速的影响特性。分析了拉杆转子的热弯曲变形特性，研究了热弯曲拉杆转子在快速起动过程中的振动特性。设计拉杆拉紧力测定试验装置，测定了不同拧紧力矩下拉杆的拉紧力，并与经验公式进行对比分析。为了减小拉杆转子组装过程中拉杆拉紧力之间的差别，采用立式组装、对称交叉拉紧和分布拉紧等三种组装方法。在拉杆转子动力学试验台上测得不同拧紧力矩下拉杆转子的动力学响应，研究了拉杆转子临界转速随拉紧力的变化规律。试验结果与理论分析的对比分析定性验证了理论模型和方法的正确性。更多还原

【Abstract】 Tie-bolted fastened rotor is widely adopted in heavy duty gas turbine for powerplant and aeroengines. In order to research the gas turbine technology independentlyin our country, the dynamics of tie-bolted fastened rotor with noncontinuousstructrue and under complicate temperature distribution is one of the key contents ofgas turbine technology. This paper aimed at the tie-bolted fastened rotor, studied theelastic-plastic contact of rough surfaces, investigated the method for the dynamicsmodeling and analysis of rotor with the consideration of temperature distribution.With the consideration of elastic-plastic contact between discs, the dynamicalcharactistics of tie-bolted fastened rotor were studied, the influence of axialtemperature distribution on the dynamics of tie-bolted rotor was analyzed, and thethermal bending of tie-bolted fastened rotor due to nonuniform circumferentialtemperature distribution was studied, the vibration charactistics of a tie-boltedfastened rotor with thermal bending during fast start up was investigated, whichcould provide a method and theory reference for the design and analysis oftie-bolted dynamical problems. The main content of this work include:For the contact problem between the discs of tie-bolted fastened rotor, theelastic-plastic contact behavior of a single asperity was studied based on finiteelement study and the single asperity elastic-plastic contact model which wassuitable for a wider range of interference was established. The elastic-plastic contactof rough surfaces was modeled based on the rough surface statistical model, and theelastic-plastic contact behaviors of rough surface were studied. The influences ofplasticity index on the elasitc-plastic contact behaviors of rough surfaces wereinvestigated. The surface roughness plasticity index and material propertiesplasticity index were defined to study the influences of surface roughness andmaterial properties on the contact behaviors of roughness seperately. The resultscould be a theory reference for the design and analysis of elastic-plastic contact ofrough surfces.In order to study the influence of axial temperature distribution on dynamics ofa rotor, a beam element with considering the variable axial parameters was proposedbased on the conventional beam element and the polynomial forms of the variationof axial parameters. A tapered rotor was modeled and studied, and the influences oftapered parameters on the dynamical characteristics of rotor were investigated.Based on the variation of Yang’s modulus with temperature, a rotor model with theconsideration of axial temperature was established, and the axial temperaturedistribution on the rotor dynamics were studied. The proposed element could provide a new method to consider the variable axial parameters in rotor finitemodeling.For the thermal bending of gas turbine rotor, the temperature distribution onrotor section was computated and studied based on finite difference method. Withthe principle of equivalent deformation, the equivalent thermal moment of thetemperature distribution on rotor section was proposed and the thermal deformaitonof a rotor under different axial distributions of the seciton temperature differencewas studied. The dynamical characteristics of a thermal bending rotor during faststart up was simulated, and the complicate vibration phenomenon under thecombination of thermal bending and unbalance was analyzed. The influence of thefading of thermal bending on the dynamics of a rotor was studied as well. Theresults could be a theory reference for the analysis and diagnosis of the vibraitonproblem during the fast start up of a gas turbine rotor.Based on the elasitc-plastic contact model of rough surfaces, the elastic-plasticcontact stiffness between discs of tie-bolted fastened rotor was studied and thedynamical model of a tie-bolted fastened rotor with the consideration ofelastic-plastic contact were established, The dynamics and its influences of atie-bolted fastened rotor were studied. A finite element model for the rotor axialtemperature was established, and the influence of thermal expansion and variation ofmaterial properties due to axial temperature distribution on the dynamics oftie-bolted fastened rotor was studied. The thermal bending of tie-bolted fastenedrotor was studied, and the dynamics of thermal bending tie-bolted fastened rotorduring fast start up was investigated.The test rig for the measurement of tighten force of rod was designed, and thetighten forces under different torques were measured, comparision with the resultsof analytical formulation was conducted. In order to reduce the difference of thetighten forces of rods, the vertical assemblage, symmetry crossing tightening andtighgen by steps were applied. The dynamical responses of tie-bolted fastened rotorwere measured under different torques, and the variations of the critical speeds withtighten forces were investigated. The experimental results were compared withtheory analysis, which validated the theory analysis.更多还原