超高压隔膜压缩机工作过程瞬态仿真及膜片应力分析

Transient Simulation and Diaphragm Stress Analysis of Ultra-High-Pressure Diaphragm Compressors

为提高超高压隔膜压缩机膜片寿命,结合压缩机热力过程、固支圆板变形以及曲柄连杆运动等基本方程,建立了隔膜压缩机气体-膜片-液压油耦合瞬态仿真模型,并基于仿真瞬态油压和气压,采用数值模拟方法,研究了排气压力达到200 MPa级和45 MPa时膜片的应力分布,分析了膜腔型线对膜片应力与寿命的影响。研究结果表明:膜片变形减小,其沿厚度方向的应力梯度随之降低;当排气压力达200 MPa级时,即使膜片接近水平位置,仍然处于受压状态,压应力达100 MPa,且膜片紧贴膜腔壁面时的最大径向应力低于基于自由变形理论的计算结果;当膜腔型线、膜片半径与厚度不变时,排气压力200 MPa级工况下的膜片径向应力相比45 MPa工况减小97 MPa;超高压下油压和气压对膜片挤压产生的压应力不可忽略,且排气压力越高,压应力越大;超高压下膜片气侧边缘位置应力幅最大,可通过增大型线挠度降低边缘径向应力及应力幅,提高膜片寿命。研究结果可为超高压隔膜压缩机膜腔型线设计提供参考。

To enhance the lifespan of diaphragms in ultra-high-pressure(UHP)diaphragm compressors,a transient simulation model is developed that couples gas-diaphragm-hydraulic oil interactions.This model integrates the fundamental equations governing the compressor’s thermodynamic processes,solid support circular plate deformation,and crank-connecting rod motion.By employing simulated transient oil and air pressures,a numerical simulation method is utilized to explore the stress distribution within the diaphragm at both 200 MPa and 45 MPa exhaust pressure levels and analyze the impact of the diaphragm cavity profile on diaphragm stress and lifespan.The research results reveal that as the diaphragm undergoes less deformation,the stress gradient along its thickness direction decreases.When the exhaust pressure reaches 200 MPa,even when the diaphragm is close to a horizontal position,it remains pressurized,with compressive stress reaching 100 MPa.Additionally,the maximum radial stress when the diaphragm is in close contact with the diaphragm chamber wall is lower than the calculated results based on free deformation theory.Moreover,when the diaphragm cavity profile,diaphragm radius,and thickness remain constant,the radial stress of the diaphragm under 200 MPa exhaust pressure decreases by 97 MPa compared to the 45 MPa condition.Hence,the compressive stress induced by oil and gas pressure on the diaphragm in ultra-high-pressure conditions is significant,with higher exhaust pressures leading to increased compressive stress.In addition,under ultra-high pressure circumstances,the stress amplitude peaks at the edge of the diaphragm’s air side.Elevating the profile deflection can mitigate edge radial stress and stress amplitude,thereby prolonging the diaphragm’s lifespan.These research findings can serve as a reference for designing diaphragm cavity profiles in ultra-high-pressure diaphragm compressors.