借助计算流体力学技术(CFD)获取四组厌氧折流板反应器(ABR,上下流室宽度比分别为2∶1、3∶1、4∶1及5∶1)的停留时间分布(RTD),并计算串联数(N)、扩散数(D/μL)及水力死区容积占比(Vd/V)等参数,以分析反应器流动、混合等水力特性;在此基础上选择最佳上下流室宽度比值,优化ABR反应器的设计.结果表明:当容积和理论水力停留时间(HRT)相同时,提高上下流室宽度比,N随之降低,最低值为4.80,而D/μL呈上升趋势,最大值为0.118;Vd/V随上下流室宽度比的增大,呈先下降后升高的趋势,比值为4∶1时Vd/V最小,仅为3.13％.选取水力效率(λ)作为反应器的水力评价指标,在2∶1 ～4∶1的流室宽度比范围内,λ相差不大,属于理想范围.综合考虑反应器流动混合特性、死区占比及水力效率,确定反应器的最佳上下流室宽度比为4∶1.%Four different anaerobic baffled reactors (ABRs) with the width ratios of upstream to downstream chamber set as 2∶ 1,3∶ 1,4∶1 and 5∶1 respectively were studied in this paper.The computational fluid dynamics (CFD) technique was employed to obtain the residence time distributions (RTD),and parameters like number of continuous stirred tanks in series (N),dispersion number (D/μL) and fraction of hydraulic dead space (Vd/V) were calculated.By analyzing the RTD curve,the flow mixing pattern and other hydraulic characteristics of the four ABRs could be achieved to determine the optimal width ratio to improve the design of ABR.Results showed that under the same volume and ideal hydraulic retention time (HRT),with the increase of width ratios,the value of N decreased (the minimum value was 4.80) while D/μL was on the rise (the maximum value was 0.118),and the fraction of hydraulic dead space tended to decrease at first and then increase.The dimension of the dead zone could be restricted to the minimal (only 3.13 ％ of the total volume) when the width ratio was 4 ∶ 1.The hydraulic efficiency (λ) was introduced as the hydraulic evaluation indicator,and the values of λ were similar when the width ratios were 2∶1,3∶1 and 4∶1,which indicated that good performances were achieved under these hydraulic conditions.Comprehensively considering the flow mixing pattern,fraction of hydraulic dead space and hydraulic efficiency of the ABRs,the optimal width ratio of upstream to downstream chamber is suggested as 4∶1.
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