半封闭螺杆制冷压缩机排气噪声模拟与试验研究

针对某R22半封闭螺杆制冷压缩机，通过动网格的划分建立充分考虑轴向排气孔口面积变化的排气流场模型，利用Fluent软件进行流场的动态数值模拟；将模拟得到的流场结果作为LMS的边界条件，模拟得到了双螺杆压缩机排气噪声频谱图；通过试验测量结果对模拟结果进行了验证；并进一步分析压缩机排气流道优化设计对气流脉动和噪声的影响。研究结果表明：模拟与试验的压力脉动最大值的误差在5%以内，噪声频谱的变化趋势基本一致；压缩机排气过程气流脉动主要集中在排气孔口处，并在排气腔内有明显衰减；光顺排气腔流道和增设周向排气导流槽，可有效减少排气过程的压力脉动；模拟和试验结果都表明：以模拟结果为依据的排气腔流道优化有效地降低了压缩机噪声，说明本文所述研究方法可指导半封闭双螺杆制冷压缩机的优化设计。

Numerical and Experimental Research on the Discharge Noise of Twin-screw Refrigeration Compressors

A physical model for the discharge process simulation of a R22 semi-hermetic twin-screw refrigeration compressors is presented. The area change of an axial discharge orifice has been taken into consideration. The dynamic numerical simulation of discharge flow fields is carried out by the software of Fluent. Then the discharge noise spectrum of the compressor is obtained by making the Fluent simulation results as the boundary conditions of LMS. An experimental study is conducted to verify the model's accuracy. A structural optimization of the compressor's discharge end is performed by the analysis of simulation and experimental results. It is concluded that the pressure pulsation in the discharge orifice is big and it is attenuated in the discharge cavity. The sleeking of discharge flow passageway and opening of radial discharge orifice is good for the whole compressor and can reduce the pressure loss significantly. Both simulation and experimental results show that the optimization reduces the noise of the compressor, indicating that the method in this paper can applied for the optimization design of twin-screw refrigeration compressors.