【作者】 王健；

【导师】 谢元华； 刘坤；

【作者基本信息】 东北大学 ， 动力工程（专业学位）， 2022， 硕士

【摘要】 干式螺杆真空泵凭借抽速范围宽、结构简单紧凑、能耗低、无油污染等优点而具有广阔的应用前景,目前已在半导体制备、航空航天、电子器件、石油化工、表面科学、食品封装等行业得到广泛应用。然而,在持续运行的恶劣工况下,高速旋转的螺杆转子受到温度的持续变化、流体的持续冲击及运转的持续不稳定,导致其运行过程中容易产生刮蹭、卡死问题,严重影响螺杆真空泵的抽气性能与使用寿命。因此,基于多物理场的螺杆泵运转态间隙设计方法研究具有较高的工程应用价值。基于啮合原理及坐标系变换法,进行螺杆转子端面型线、螺旋展开线的参数化设计及螺杆真空泵的结构设计,推导泄漏通道长度及级间泄漏量的理论公式,最终得到各级压力分布及排气温度的理论公式。分别计算三种典型工况下螺杆真空泵的压力分布及排气温度,结果将作为流场模拟及动力学模拟的边界条件参数。基于流体力学基本定律,进行额定转速下螺杆真空泵内的流场仿真,模拟螺杆泵内流体的压力分布及温度分布,并对比分析模拟计算值与理论计算值的差异性。将流场模拟结果作为边界条件,进行螺杆真空泵的热-流-固耦合模拟分析,得到运转态下螺杆转子及泵腔的热力学变形量及流体激励变形量的理论数值及分布规律,为计算热力学因素及流体激励因素对间隙值变化的影响权重及运转态间隙值分布提供数据支撑。基于转子动力学基本定律,进行额定转速下螺杆转子的动力学仿真。采用应力应变分析、模态分析及谐响应分析的模拟方法,得到螺杆转子的应力应变、固有频率、临界转速及振动响应数据,计算运转态下螺杆转子动力学变形量的理论数值及分布规律。分别研究不同流体激励、不平衡惯量、轴承刚度及结构参数对转子动力学变形量的数值影响及变化趋势,为计算动力学因素对间隙值变化的影响权重及运转态间隙值分布提供数据支撑。将上述计算得到的螺杆真空泵分别在热力学因素、流体激励因素及动力学因素下变形量的理论数值及分布规律作为基础参数,分析各因素对各处间隙影响的数值分布及权重分析,进行螺杆真空泵内部运转态间隙的理论计算,研究基于多物理场的运转态间隙的变化规律并提出运转态间隙的设计方法。为螺杆真空泵的理论设计提供参考,解决螺杆真空泵运转态下的刮蹭、卡死问题。更多还原

【Abstract】 Dry screw vacuum pump has broad application prospects with the advantages of wide pumping speed range,simple and compact structure,low energy consumption and no oil pollution.At present,it has been widely used in semiconductor preparation,aerospace,electronic devices,petrochemical industry,surface science,food packaging and other industries.However,under the severe working conditions of continuous operation,the high-speed rotating screw rotor is subject to the continuous change of temperature,the continuous impact of fluid and the continuous instability of operation,which leads to the problems of scratching and jamming during its operation,and seriously affects the pumping performance and service life of the screw vacuum pump.Therefore,the research on the operating clearance design method of screw pump based on multi physical fields has high engineering application value.Based on the meshing principle and the coordinate system transformation method,the parametric design of the screw rotor end face profile,the spiral unfolding line and the structural design of the screw vacuum pump are carried out.The theoretical formulas of the length of the leakage channel and the leakage between stages are derived,and finally the theoretical formulas of the pressure distribution and the exhaust temperature at each stage are obtained.The pressure distribution and exhaust temperature of screw vacuum pump under three typical working conditions are calculated respectively.The results will be used as boundary condition parameters for flow field simulation and dynamic simulation.Based on the basic laws of fluid mechanics,the flow field in the screw vacuum pump at rated speed is simulated,the pressure distribution and temperature distribution of the fluid in the screw pump are simulated,and the differences between the simulated and theoretical values are compared and analyzed.Taking the flow field simulation results as the boundary conditions,the thermal fluid solid coupling simulation analysis of the screw vacuum pump is carried out,and the theoretical values and distribution rules of the thermodynamic deformation and fluid excitation deformation of the screw rotor and pump cavity under the operating state are obtained,which provides data support for calculating the influence weight of the thermodynamic factors and fluid excitation factors on the change of the clearance value and the distribution of the clearance value under the operating state.Based on the basic laws of rotor dynamics,the dynamic simulation of screw rotor at rated speed is carried out.Using the simulation methods of stress-strain analysis,modal analysis and harmonic response analysis,the stress-strain,natural frequency,critical speed and vibration response data of the screw rotor are obtained,and the theoretical value and distribution law of the dynamic deformation of the screw rotor under the running state are calculated.The numerical influence and change trend of different fluid excitation,unbalanced inertia,bearing stiffness and structural parameters on the rotor dynamic deformation are studied respectively,which provides data support for calculating the influence weight of dynamic factors on the change of clearance value and the distribution of operating clearance value.Taking the theoretical value and distribution law of the screw vacuum pump deformation under thermodynamic factors,fluid excitation factors and dynamic factors as the basic parameters,the numerical distribution and weight analysis of the influence of various factors on various clearances are analyzed,the theoretical calculation of the internal operating clearance of the screw vacuum pump is carried out,the variation law of the operating clearance based on multiple physical fields is studied,and the design method of the operating clearance is proposed.It provides a reference for the theoretical design of screw vacuum pump,and solves the problems of scraping and jamming of screw vacuum pump.更多还原