基于Creo的CO₂气体混合器结构设计与流体仿真

Structural Design and Fluid Simulation of CO₂ Gas Mixer Based on Creo

摘要: 针对YY/T 0671-2021标准中正压通气面罩“避免重复呼吸的保护”试验对CO₂浓度稳定性与均匀性的要求，本文设计了一种用于模拟呼出气体的CO₂气体混合器。基于Creo Parametric建立三维结构模型，并采用Flow Analysis模块对其内部流场进行数值仿真。通过构建多工况CO₂体积分数(5%、10%、25%)条件，分析混合器内流线分布及出口浓度均匀性，并以出口截面浓度的变异系数(COV)作为评价指标。结果表明，该混合器在不同浓度工况下均可实现稳定输出，COV均小于3%，满足稳定性与均匀性的要求。研究结果表明，所设计混合器能够有效提升重复呼吸试验中CO₂模拟气体的稳定性与可靠性，为正压通气面罩“避免重复呼吸的保护”试验方法优化提供技术支撑。

Abstract: In response to the requirements for CO₂ concentration stability and uniformity in the “protection against rebreathing” test for positive-pressure ventilation masks specified in the YY/T 0671-2021 standard, this paper describes the design of a CO₂ gas mixer for simulating exhaled gas. A 3D structural model was created using Creo Parametric, and the internal flow field was numerically simulated using the Flow Analysis module. By simulating multiple CO₂ concentration conditions (5%, 10%, and 25%), the study analyzed the flow line distribution within the mixer and the uniformity of the outlet concentration, using the coefficient of variation (COV) of the outlet concentration as the evaluation metric. The results indicate that the mixer achieves stable output under various concentration conditions, with a COV consistently below 3%, thereby meeting the requirements for stability and uniformity. The study results indicate that the designed mixer can effectively improve the stability and reliability of CO₂ simulation gas in rebreathing tests, providing technical support for optimizing the “rebreathing prevention” test method for positive-pressure ventilation masks.