基于变风量控制的受控环境压差控制应用研究

Application research on controlled environmental pressure difference control based on variable air volume control

压差控制是受控环境气流控制的核心部分,能为实现定向气流的控制目标和提升实验室整体安全性提供有力保障。基于围护结构气密性特征、压力梯度控制需求、快速扰动源等因素,以普通实验室、普通洁净室和气密性生物安全实验室为例,对变风量下的余风量控制、直接压差控制、串级控制3种压差控制方式的适用性、影响因素及应对策略进行了研究,并对空气渗透特性方程的适用性进行了探讨。研究表明:普通实验室和普通洁净室的围护结构孔口和缝隙处空气流动接近于湍流状态,流动指数n可取0.5;气密性实验室的围护结构缝隙长度和水力直径的比值较大,层流占主导地位,流动指数n取值趋近于1.0。

Pressure difference control is a core part of controlled environmental airflow control,providing robust safeguards to achieve directional airflow control objectives and enhance overall laboratory safety.Based on the factors such as airtightness characteristics of the envelope,pressurization control requirements,and fast disturbances,this study taking ordinary laboratories,standard cleanrooms,and airtight biosafety laboratories as examples,explores the applicability,influencing factors,and mitigation strategies of three pressure difference control methods including volumetric flow tracking control,direct pressure difference control,and cascade control under variable air volume(VAV)control,and the applicability of the air infiltration characteristic equation.The research shows that in ordinary laboratories and standard cleanrooms,airflow near intentional openings and gaps in the envelope approaches turbulent flow,with a flow exponent(n)value of 0.5.In contrast,in airtight laboratories,where the ratio of gap length to hydraulic diameter in the envelope is high,laminar flow predominates,with the flow exponent(n)value approaching 1.0.