To analyze the complex spatiotemporal evolution law of the high-speed jet flow field in a liquid-ring pump ejector, both the classic and spectral proper orthogonal decomposition (SPOD) methods were introduced to decompose the transient flow field based on the numerical large eddy simulation. The proper orthogonal decomposition (POD) reduced order model (ROM) of the complex flow in the ejector was established to analyze the transient characteristics and reconstruct the flow field. The spatial mode characteristics of density, pressure and vorticity field, and the frequency domain characteristics of mode coefficients were analyzed. The results show that the spatiotemporal decoupling analysis of a high-speed jet flow field can be accomplished by the POD and SPOD methods. A large-scale symmetric coherent structure is formed in the shear layer of the first two modes of vorticity, and a small-scale antisymmetric structure is formed at the trailing edge of the jet flow for the third and fourth modes. This reflects the evolutionary characteristics of the jet shear vortex. There is a significant spatial correlation between the density and pressure modes, reflecting that the evolution of the two structures has important correlation characteristics. The spectral analysis of the mode coefficients shows that the dominant frequencies of 1250 Hz and 18 kHz correspond to the self-excited oscillation frequency of shock waves and the vortex shedding frequency. The POD-ROM can reconstruct the high-speed flow field of the ejector with enough accuracy using the first 30-order modes, and the root mean square error and mean absolute percentage error for the velocity prediction are 0.48% and 0.24%, respectively.

为分析液环泵喷射器中高速射流流场复杂的时空演化规律，在数值大涡模拟的基础上，引入经典和谱真正交分解（SPOD）方法对瞬态流场进行分解。 . 建立喷射器内复杂流动的适当正交分解(POD)降阶模型(ROM)，分析瞬态特性并重构流场。分析了密度场、压力场和涡度场的空间模态特征，以及模态系数的频域特征。结果表明，可以通过POD和SPOD方法完成高速射流流场的时空解耦分析。前两种涡度模态的剪切层形成大尺度对称相干结构，第三和第四模态在射流后缘形成小尺度反对称结构。这反映了射流剪切涡的演化特征。密度和压力模式之间存在显着的空间相关性，反映了两种构造的演化具有重要的相关性特征。模态系数的谱分析表明，1250 Hz和18 kHz的主频分别对应于冲击波的自激振荡频率和涡旋脱落频率。POD-ROM 可以使用前 30 阶模态以足够的精度重建喷射器的高速流场，