共查询到20条相似文献,搜索用时 93 毫秒
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项目中的市政道路位于已建城区,历年暴雨期间内涝严重,因改造条件受限,拟仅通过雨水管网改造解决内涝问题.为制定经济合理的管网分期改造方案、准确分析内涝成因、预估不同降雨条件时改造方案的实施效果,项目采用鸿业暴雨排水及低影响开发模拟系统进行模型构建,并采用传统推理公式计算法辅助分析.通过软件模拟对现状管网重现期进行评估;对近期管网改造方案在10年一遇、20年一遇、50年一遇降雨条件时的道路积水情况模拟,以验证近期改造效果;通过反复试算最终确定了50年一遇内涝设计标准下的管网改造方案.项目采用鸿业暴雨排水及低影响开发模拟系统辅助方案设计,利用其超标重现期下内涝设计的功能,软件操作以AutoCAD为平台,避免了软件输入数据的处理、转换以及软件模块间的外部耦合,操作过程简单、模型构建时间短.与传统推理公式法计算相比,优化了管道管径,由于该软件目前较少应用于超标重现期下的道路内涝整治设计,可为类似内涝整治工程提供技术参考,且对数学模型法的推广应用具有非常重要的意义. 相似文献
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雨水调蓄池作为城市内涝防治的一种重要措施,其有效容积的确定在设计过程中极为重要。以云南省某市为例,采用传统公式法计算与SWMM软件模拟2种方法得到调蓄池有效容积,对2种方法的结果进行比较分析,结果表明在低重现期下公式法计算值要大于软件模拟值,而在高重现期下软件模拟值将大于公式计算值。 相似文献
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<正> 一、用途及算法简介 1、本程序用BASIC语言,PC—1500机编程。 2、已知暴雨强度公式,经流系数,地面集水时间,设计重现期,汇水面积,地面标高,管道起点埋深,进行雨水管道的管径、坡度、流速、坡降、管道输水能力、管道起点终点标高及埋深等的计算。 3、本程序适用于平坦地形,也适用于坡度变化较大的地形。 相似文献
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区别于目前的行标法,本实验使用电位法对五氟化碘进行定量分析。通过一步法将待检样完全还原为I–和F–,采用电位法分别检测溶液中I–和F–含量。新方法操作步骤少,化学试剂消耗少,操作过程安全简单,减小了实验结果的误差,提高了分析结果的重现性。 相似文献
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为了提升建筑工程的整体质量,对建筑混凝土材料的强度进行测定,选取多个相同标准的立方体试件,将其分别置于标准养护和同条件养护条件下完成性能测试。采用钻芯法对结构实体混凝土试件的强度进行测试。该方法可直接在结构试件上钻取芯样,在抗压强度测量过程中,不需要借助其他物理量完成强度的换算,有利于提升试验结果的可靠性。将试件的等效龄期与成熟度作为主要依据,精准记录不同龄期下试件的变化情况。 相似文献
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Zhaoyou Zhu Guoxuan Li Yao Dai Peizhe Cui Dongmei Xu Yinglong Wang 《Frontiers of Chemical Science and Engineering》2020,14(5):824
The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification. 相似文献
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分割式热泵精馏流程的优化设计及运行调优 总被引:5,自引:0,他引:5
从系统能量平衡的角度,提出了适合于分割式热泵精馏优化设计和运行调优的系统参数———压缩机进气量,建立了以年总费用最小为目标函数的优化设计数学模型和以年操作费用最小为目标函数的优化运行数学模型。以酒精精馏为例,利用Aspenplus模拟软件对此流程进行了优化计算。与常规精馏相比,此流程节能效果和经济效益非常显著。文中还分析了优化结果的运行调优问题。 相似文献
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For a distillation system, in which relative volatility is large in low composition range and small in high composition range, using separate heat pump distillation (SHPD) can markedly save energy. In this paper, vapour flow rate to compressor is proposed as a parameter for system optimization, from the viewpoint of system energy balance. This parameter can be used for both optimal design and optimal operation of SHPD. Mathematical models for optimal design and optimal operation are formulated to minimize total annual cost and annual operating cost respectively. Optimal design of SHPD is performed and evaluated through process simulation, for a typical case study for the distillation of ethanol‐water system. The results show that SHPD has notable energy saving and economic benefit when compared with conventional distillation. Optimal operation of SHPD is also evaluated for changes in feed composition which is an operating variable. 相似文献
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隔壁塔的优化设计涉及多个变量且变量之间存在复杂的相互作用关系,这不仅提高了隔壁塔的设计难度,而且制约了其在工业应用方面的潜力。为了解决这一问题,本文提出了一种利用响应面法(RSM)耦合非支配遗传算法(NSGA-Ⅱ)对隔壁塔进行多目标优化设计的方法。首先,确定设计变量并利用单因素分析确定各变量水平,采用BBD(Box-Behnken)方法进行实验设计,并通过数值模拟计算年度总费用(TAC)和再沸器热负荷(Q)的目标函数;然后利用方差分析(ANOVA)评估各回归模型的统计重要性,并用二次多项式形式表示;最后通过NSGA-Ⅱ算法对响应面模型进行优化,计算Pareto前沿获得一系列优化方案。研究表明,相比于传统流程,采用该方法对隔壁塔进行分析和优化,能在降低TAC的同时有效降低Q,为隔壁塔的优化设计提供一种新思路。 相似文献
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Abstract. Confidence bounds for the spectral density of a stationary time series are derived. A unified method begins with the autoregressive spectral estimate and produces both confidence intervals at single frequencies chosen a priori and a simultaneous confidence band for multiple a posteriori comparisons. The crux is optimization of a quadratic form subject to the constraint imposed by the F -statistic. An approximate method that may produce tighter bounds is described. The former methods are demonstrated on the Waldmeier annual mean sunspot numbers. 相似文献
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This paper presents the numerical simulation of inducing residual stresses on equal channel angular pressed (ECAP) magnesium alloy by shot peening process. Mg-Al-Mn (AM) series magnesium alloy was ECAP processed up to 4 passes using route BC. Microstructures were analysed and grain size reduced from 100 µm for the as-received sample to 3 µm for ECAP 4 pass sample. Tensile test was carried out and maximum tensile strength was found in ECAP 2 pass sample and decreased with higher ECAP passes. Grain refinement was characterized by optical microscopy, electron backscatter diffraction analysis (EBSD) and X-ray diffraction (XRD). Material (tensile) behaviour of 2 pass sample was implemented for finite element modelling. A finite element method was used to estimate the intensity of residual stresses developed due to shot peening in ECAP processed AM80 alloy. Simulation was done with different boundary condition such as impact velocity, geometry of shot-peen media, angle of impact and multiple impacts. The results are presented and the relationship between process parameters and the intensity of residual stresses are discussed. Increase in velocity of shot peening media showed an increase in the magnitude of residual stresses. Change in geometry of shot media altered the contact area between target and shot media during impact which influenced the magnitude of residual stresses and coverage area. The magnitude of residual stresses varied with the angle of impact and the multiple repeated impacts showed that the effective depth of residual stresses increased with the number of impacts. 相似文献
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浮头法兰计算方法讨论 总被引:6,自引:0,他引:6
按照目前我国压力容器设计标准中所给出的浮头法兰厚度计算公式进行计算时,会出现前后两次的厚度计算不一致的问题,压力容器计算软件SW6-1998的现版本在计算中采用叠代方法以避这个问题,为了避开出现死循环的现象,软件以循环中的最大值输出,本文对标准中公式的来源进行了分析,找出了出现以上问题的原因,然后,对标准中给出的公式形式和软件可采用的合适计算方法进行了讨论。 相似文献