空间除臭设计风量理论计算方法探究

Research on the Theoretical Calculation Method of Air Volume for Spatial Deodorization

为了探究持续通风作用下空间污染物浓度变化规律,明晰除臭设计风量的定量计算方法,基于恒定污染物散发量,利用质量守恒原理,建立了空间除臭简化模型,推导并求解了空间污染物浓度变化基本方程,其通解表明浓度函数随时间的增长呈指数变化。结合垃圾处理工程实际情况,探讨了浓度函数中考虑污染物体积散发项的必要性;通过浓度函数极限求解,获得了极限风量求解方法。结合设计浓度,初始浓度和新风污染物浓度的关系,论述了浓度函数增减性与临界风量的关系,阐明了持续通风并不总是具有“稀释”作用,特定条件下,空间内平均浓度随时间增长呈增加趋势的结论。结合临界风量和极限风量分析,给出设计风量推荐选用区间及计算流程,并推导了总换气次数的估算公式。

In order to explore variation law of the spatial pollutant concentration under continuous ventilation,the quantitative calculation method of deodorization design air volume is clarified.Based on the constant pollutant emission and principle of mass conservation,a simplified model of spatial deodorization was established,and the basic equation of spatial pollutant concentration change was derived and solved,the general solution shows that the concentration function changes exponentially with time;Combined with the actual situation of the garbage disposal project,the necessity of considering the pollutant volume emission term in the concentration function is discussed;through the limit solution of concentration function,the method for solving the limit air volume is obtained;Combining the relationship between the design concentration,initial concentration and fresh air pollutant concentration,the relationship between the increase and decrease of density function and the critical air volume is discussed,and it’s clarified that continuous ventilation doesn’t always have a"dilution"effect.Under certain conditions,the average concentration in space shows an increasing trend with time;Combined with the analysis of the critical air volume and the limit air volume,the recommended selection interval and calculation process of the design air volume are given,and the estimation formula of the total air change rate is derived.