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在利用短行程法构建行驶工况的过程中,为综合考虑短行程的典型性和行驶工况的代表性,将二者量化并作为多目标优化过程中的两个目标函数,引入非支配排序遗传算法Ⅱ(nondominated sorting genetic algorithmⅡ,NSGA-Ⅱ)对短行程的选择进行优化。将NSGA-Ⅱ优化方法与常用的短行程选择方法进行对比,在相同时间内,随机选择法、相关性法、距离法和NSGA-Ⅱ分别构建了7 582、7 209、9 615和20个候选行驶工况。结果显示,4种方法中,在整体上,NSGA-Ⅱ产生的行驶工况集中在代表性较高的区域同时使得构成行驶工况的短行程整体上典型性较高;在最优工况的比较中,NSGA-Ⅱ的最优工况与原始数据的特征参数相对误差最小,包含的短行程到离簇中心的平均距离最短,表明采用NSGA-Ⅱ算法对短行程选择过程进行优化有助于从多个角度提升行驶工况的构建质量。 相似文献
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针对现有有机朗肯循环单目标优化设计的局限性,从热力性、经济性等多方面对有机工质低温余热发电系统进行多目标优化设计.以系统效率最大和总投资费用最小为目标函数,选取透平进口温度、透平进口压力、余热锅炉节点温差、接近点温差和冷凝器端差等5个关键热力参数作为决策变量,利用非支配解排序遗传算法(NSGA-II)分别对采用R123、R245fa和异丁烷的有机工质余热发电系统进行多目标优化,获得不同工质的多目标优化的最优解集(Pareto最优前沿),并采用理想点辅助法从最优解集中选择出最优解及相应的系统最佳热力参数组合.结果表明:在给定余热条件下,从热力性能和经济性两方面考虑,R245fa是最优的有机工质,从多目标优化的最优解集中选择出的最佳效率为10.37%,最小总投资费用为455.84万元. 相似文献
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针对新能源发电与抽水蓄能电站联合发电系统,提出一种多时间尺度优化调度策略,并提出一种结合快速非支配排序遗传算法(NSGA-Ⅱ)和模式搜索算法的NSGA-Ⅱ-PS算法,该策略针对不同的时间尺度分别设定目标函数与约束条件,对比NSGA-Ⅱ与NSGA-Ⅱ-PS在解决本调度问题结果上的优劣性。在日前、日中时间尺度对联合系统进行优化调度,制定调度计划。结果表明:在高比例新能源消纳的基础上,新能源发电与抽水蓄能电站联合系统多时间尺度优化调度可在日前、日中尺度实现联合系统经济安全运行。 相似文献
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基于遗传算法的无功功率优化与控制专家系统开发 总被引:1,自引:4,他引:1
针对电力系统中无功功率优化问题建立了数学模型,利用函数连接网络将多目标问题转化为单目标无功优化问题,采用免疫遗传算法进行求解。 提出了分区分层的多变电所电压无功协调控制专家系统的设计思想。该系统具有较高优化精度的同时求解过程较为简单。 相似文献
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生物质气化过程是一个复杂的多目标非线性过程。通过对气化过程的机理分析,针对麦秸和玉米秸这2种软质秸秆类生物质原料特性,建立了气化过程的优化目标函数。在此基础上,采用多目标遗传算法对该目标函数进行优化设计计算。计算结果表明,该目标函数对生物质气化过程参数优化具有良好效果,也验证了该算法对于全局优化以及解决复杂非线性问题的有效性。 相似文献
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A model is developed to simulate a cross‐flow heat exchanger, including fins, in the wall of which thermoelectric generators are sandwiched. Such a system could be used for waste heat recovery. The model is used to optimize the device based on several objective functions: total volume, total number of thermoelectric modules, power output, and pumping power. The design variables are the local distribution of modules and of current, the shape of the fins, and the division of the heat exchanger in sub‐channels. Pareto fronts are achieved with a multi‐objective genetic algorithm, and are presented here. The results show that the number of sub‐channels in the heat exchanger has a larger impact on the overall performance than the fin geometry for this particular problem. Also, the net power output is mostly correlated to the number of thermoelectric modules, and less to the heat exchanger volume. Various relations between the different competing objectives are shown and analyzed. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Anurag Singh M.P. Maiya S. Srinivasa Murthy 《International Journal of Hydrogen Energy》2017,42(22):15226-15235
The absorption and desorption performances of a solid state (metal hydride) hydrogen storage device with a finned tube heat exchanger are experimentally investigated. The heat exchanger design consists of two “U” shaped cooling tubes and perforated annular copper fins. Copper flakes are also inserted in between the fins to increase the overall effective thermal conductivity of the metal hydride bed. Experiments are performed on the storage device containing 1 kg of hydriding alloy LaNi5, at various hydrogen supply pressures. Water is used as the heat transfer fluid. The performance of the storage device is investigated for different operating parameters such as hydrogen supply pressure, cooling fluid temperature and heating fluid temperature. The shortest charging time found is 490 s for the absorption capacity of 1.2 wt% at a supply pressure of 15 bar and cooling fluid temperature and velocity of 288 K and 1 m/s respectively. The effect of copper flakes on absorption performance is also investigated and compared with a similar storage device without copper flakes. 相似文献
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对国内现有内燃机车用热交换器的传热机理和结构进行了分析、比较和研究,指出热交换器传热强化应采取的措施,并针对光管热交换器、螺旋扁管热交换器、螺旋隔板热交换器作了性能对比研究,指出螺旋隔板热交换器具有较高的冷却能力。 相似文献
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A variational principle is established for the heat balance in a finned tube heat exchanger used in hydride hydrogen storage systems, an approximate solution is obtained, which can be used for optimal design and study on effects of various parameters on the thermal property of the heat exchanger. 相似文献
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This paper presents a procedure for minimizing the cost of a shell‐and‐tube heat exchanger based on genetic algorithms (GA). The global cost includes the operating cost (pumping power) and the initial cost expressed in terms of annuities. Eleven design variables associated with shell‐and‐tube heat exchanger geometries are considered: tube pitch, tube layout patterns, number of tube passes, baffle spacing at the centre, baffle spacing at the inlet and outlet, baffle cut, tube‐to‐baffle diametrical clearance, shell‐to‐baffle diametrical clearance, tube bundle outer diameter, shell diameter, and tube outer diameter. Evaluations of the heat exchangers performances are based on an adapted version of the Bell–Delaware method. Pressure drops constraints are included in the procedure. Reliability and maintenance due to fouling are taken into account by restraining the coefficient of increase of surface into a given interval. Two case studies are presented. Results show that the procedure can properly and rapidly identify the optimal design for a specified heat transfer process. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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蚁群算法在换热网络优化中的应用 总被引:1,自引:0,他引:1
提出将蚁群算法应用于换热网络优化中,按照相等的能量份额将各股热流体分解成能量集合,热流体能量通过换热器在与冷流体换热的过程中得到分配,换热器单元面积得到相应地调整.能量分配过程中换热网络得到优化,从而使年综合费用减少的换热器面积不断积累,最终形成了一个最优的换热网络结构.通过具体算例验证了该方法的可行性和有效性,最终优化的结果证明该方法具有较强的全局搜索能力,能够应用于复杂换热网络的优化问题中. 相似文献
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基于感知器模型本文提出一种换热器网络优化新算法,在遗传迭代过程中,依据目标函数的适应值,该算法不断调节感知器的权值,使感知器以随机方式搜索网络拓扑结构和运行参数。经过本文的计算表明:这一算法对于多维、多峰、非凸函数也具有很好的适应性,能够有效地克服传统方法(混合整数非线性优化)的不足之处。 相似文献