局部变截面无油涡旋压缩机的热动力耦合特性研究

For inherent characteristics restriction of single profile scroll machine and the impacts of oil-free and high temperature on scroll compressor performance, the structure of present scroll compressor can not meet the requirement of new energy automobile. Local variable thickness scroll profile is presented. The new profile is built based on meshing mechanism and geometric characteristics. The numerical simulation method is used to solve the distribution of temperature field and pressure field. The deformation and stress of scrolls are investigated under the condition of forced by temperature field and pressure field coupling. The results provide guidance to quantitative design of local variable thickness scroll profile. A thermodynamic coupling mathematical modeling based on energy and mass balances is established. The modeling can reflect the relations between its design parameters and its performance index. Suction gas heating, radial and flank leakage, heat transfer between the gas, scroll wraps and plates are considered in the thermodynamic modeling. The influences of geometrical properties, dynamic properties, thermodynamic properties and friction properties on scroll compressor performance are quantitatively and comprehensively studied under the oil-free operation condition. The interplay and coupling mechanism of dynamic properties and thermodynamic properties are gotten. It can provide reverse reference for design of local variable thickness scroll profile. The research results will achieve the change from empirical design to intelligence integrated optimize design and establish the theoretical foundation for development of new and high efficient oil-free scroll compressor.

由于目前单一规则涡旋型线固有特性的限制以及无油和高温对涡旋压缩机性能的影响，现有结构形式的涡旋压缩机难以适应新能源汽车的应用要求。本项目提出基于局部变截面型线的全新结构，从涡旋型线的啮合机理和几何特性出发，构建全新的涡旋型线，采用数值模拟方法求解稳态温度场和压力场的分布，研究在稳态温度场和压力场耦合作用下涡旋型线的应力分布及变形机理，从而指导局部变截面涡旋型线的定量化设计。以能量和质量守恒为基础，充分考虑吸气加热、轴向和径向泄漏、气体与涡旋齿的传热，建立设计参数与性能指标间的热动力耦合数学模型，研究无油状况下涡旋盘的几何参数结构、动力学、热力学及摩擦学对整机性能的影响规律，揭示热力学与动力学特性的相互影响和耦合机理，从而为局部变截面涡旋型线的设计提供反向参考，实现无油涡旋压缩机从经验设计到智能优化设计的过渡，进而为新型高效无油涡旋压缩机的开发奠定理论基础。

项目瞄准无油涡旋压缩机优化设计领域的学科前沿和制约瓶颈，针对无油涡旋压缩机的高温和无油润滑特点，综合研究涡旋几何参数结构、涡旋盘的动力学和热力学耦合作用下对整机系统的影响规律。基于多目标优化研究全齿啮合条件下型线的几何特性，揭示变截面涡旋型线的自身特征参数对几何特性的影响机理，构建变截面涡旋型线的完整理论；采用基于控制体积法和无网格法构建涡旋齿非稳态传热模型，模型中充分考虑工作气体、涡旋齿、涡旋盘及各工作部件之间的相互传热，通过PISO算法并结合CFD模拟求解压缩腔内部流体运动规律以及速度场、温度场和压力场分布，研究在稳态温度场和压力场耦合作用下涡旋型线的变形机理，从而指导局部变截面涡旋型线的定量化设计，将数值模拟、工程仿真分析以及试验相结合来构建最优化的局部变截面涡旋型线；建立基于局部变截面无油涡旋压缩机的数学模型，充分考虑工作过程中的吸气加热、各部件的传热、轴向和径向的泄漏以及气体力，模拟气体从吸气、压缩到排气整个过程中体积、压力、温度和质量随曲轴转角的变化规律，详细分析研究局部变截面几何结构特性、运行参数、涡旋盘的热力特性以及动力特性对整机系统性能的影响规律，使热动力耦合数学模型能够更加真实和准确的反映无油涡旋压缩机的工作过程和性能特点，从而全面而深入的揭示设计参数与性能指标间的复杂耦合机理，为局部变截面涡旋型线的设计提供有效反馈。本研究突破了传统涡旋机械型线理论设计与整机气、热、动力耦合设计相互脱节的单向性设计方法，提出了将热动力耦合、数值模拟、工程仿真分析以及试验相结合来进行局部变截面涡旋型线的设计，为实现无油涡旋压缩机从传统的经验、半经验设计过渡到智能优化设计提供了强有力的关键技术支撑，具有重要的理论意义和工业应用价值。