目的 研究枕形袋式气调包装气体置换过程的三维流场， 改进气体置换装置的结构。方法 以BBFG-120枕式包装机为物理模型， 设计一种枕形袋式气调包装机气体置换新结构； 建立传统结构与新结构气体置换装置的物理和数值模型； 使用Gambit建立分析模型并划分网格， 应用Fluent软件对气体置换过程进行模拟分析； 建立评价气体置换装置性能的指标， 分析气管置入位置与气管数量对气体置换性能的影响。结果 相较于传统结构， 新结构具有气体置换率较高、 气体耗气量较低、 气体流动平稳和压力分布均匀等特点。结论 新结构在各方面的性能均优于传统结构， 为袋式气调包装机的设计提供了参考。

This study aimed to investigate the three-dimensional flow field simulation of the gas displacement process during modified atmosphere packaging with Pillow-bag, so as to improve the structure of the gas displacement device. One kind of gas replacement new structure of pillow bag packaging machine was designed based on BBFG-120 pillow packing machine; The physical and numerical models of gas replacement device was established which include new structure and the traditional structure; The Gambit software was applied to establish an analysis model, and then the numerical simulation of the gas-flow field was conducted using the Fluent software; The evaluation indexes of the performance of gas displacement device were established and the effect of the pipe′ s position and amount on the properties of gas replacement was investigated. Compared to the traditional structures, the new structure has the following advantages:higher rate of gas replacement, lower consumption of gas, smooth gas flow, and uniform pressure distribution. The new structure′ s performance is better than traditional structures in all aspects.