混沌变异粒子群算法在水库供水调度规则制定中的应用

本文针对基于调度图规则的水库供水调度问题,建立了以水库供水保证率高且缺水量少为目标的优化调度模型。同时应用混沌变异减缓粒子群算法收敛速度,当算法进化停滞步数大于停滞步数阀值时,随机选取其中20%的粒子进行混沌变异操作,将原本聚集的粒子群"驱散开来",达到增加种群多样性、避免算法早熟收敛的目的,并将该算法引入到调度图的获取中。并以白石水库为例,得到了满足各项用水保证率的水库调度图,验证了该方法的可行性。     

蚁群生成树算法研究

应用蚁群生成树算法搜索了有34个节点的连接图的生成树,并采用正交设计法和均匀设计法进行了参数优化配置方法研究。结果表明:对于参数较多的蚁群算法,应用正交设计法和均匀设计法进行参数优化配置是一种可行且有效的途径,可有效提高蚁群算法的收敛速度,在求解精度上也有一定优势;充分发挥人类智能与仿生物智能的各自优势是克服单纯靠智能优化方法随机搜索缺点的关键;当蚂蚁数目为100、信息素相对重要性因素为0.3、信息素衰减系数为3.6、信息素挥发系数为0.4、信息素增加强度系数为14时,蚁群生成树算法效果最佳。     

浅谈郭公庄水厂的工艺设计及优化

郭公庄水厂是南水北调水进京后第一座接纳南水并处理南水的新建给水处理厂。郭公庄水厂采用澄清、臭氧—活性炭吸附、超滤膜过滤、紫外线加次氯酸钠消毒的处理工艺。通过对机械加速澄清池布置形式、设备选型、结构做法的优化设计,以及对活性炭吸附池改为炭砂滤池的工艺设计优化,使得该水厂在适应南水北调水源、工艺单元互补、方便运行管理、保证施工质量等方面有了进一步的提高,进而满足首都供水的安全和出水水质要求。     

风-水-火电互补系统中风电穿越功率的研究

针对风电容量与风-水-火电互补系统稳定性的关系问题,研究了风电机组的数学模型,搭建了风-水-火电互补系统的仿真模型.将遗传算法(GA)应用于风电穿越功率的研究,建立了基于遗传算法的风电容量的优化数学模型,构造了适值函数.对实际电网中的风电容量进行了优化编程计算和仿真,优化和仿真结果虽有差异,但很近似,验证了所建优化数学模型的合理性及遗传算法应用于风电穿越功率计算的可行性.     

基于粒子群算法的水电站中长期优化调度研究

以洪家渡水电站为例,探讨了粒子群算法在水电站中长期优化调度的应用方法及效果。实例计算结果表明,该算法可以求解复杂约束条件的非线性水库优化调度,精度高、收敛速度快,为解决水电站中长期优化调度问题提供了一种有效的方法。     

Global scope assessment: A novel method and its application to the Chinese paper industry

We strongly suggest an idea we call Global Scope Assessment (GSA) on the basis of popular Life Cycle Assessment and Environomics. It is used to justify the industry development pattern in a region (country) considering the specific regional resources conditions. In terms of GSA, the greatest synthetic benefit is expected while taking full advantage of regional comparative superiority and the worldwide distribution of related industry links. As an example, we choose Chinese paper industry to be the subject for application of GSA and the optimal industry links distribution among related countries is obtained. Our study indicates that the adjustment of industry structure should be a fair approach to relieve the pressure from environment and resources and to balance the contradiction between development and resources.     

Monte-Carlo simulation and performance optimization for the cathode microstructure in a solid oxide fuel cell

A 3D micro-scale model is developed to simulate the transport and electrochemical reaction in a composite cathode. This model takes into account the details of the specific cathode microstructure such as random pore structure, active TPB (three phase boundary) site distribution, particle size and composition and their interrelationship to the charge transfer and mass transport processes. Especially, the pore structure and mass diffusion were incorporated into this model. Influence of the microsturcture parameters on the performance was investigated by numerical simulations.     

Turbulent natural convection in an enclosure with localized heating from below

This study reports the results of a numerical investigation of turbulent natural convection in a square enclosure with localized heating from below and symmetrical cooling from the vertical side walls. The present study simulates the case of an accidental heat generation due to fire in a typical isolated building of a nuclear reactor or electronic components cabin. The source of fire is considered to be centrally located at the bottom wall with different heated widths, which is assumed to be either isothermal or with isoflux. For the purpose of the analysis, the source length is varied from 20 to 80% of the total width of the bottom wall. The top wall and the unheated portion of the bottom wall are considered to be adiabatic, whereas sidewalls are isothermal. Steady as well as transient forms of two-dimensional Reynolds–Averaged-Navier–Stokes equations and conservation equations of mass and energy, coupled with the Boussinesq approximation, are solved by the control volume based discretisation method employing the SIMPLE algorithm for pressure–velocity coupling. Turbulence is modeled using the standard k–ε model. Rayleigh number, Ra, based on the enclosure height is varied from 10⁸ to 10¹². Stream lines and isotherms are presented for various combinations of Ra and the heated width. A double cell flow pattern is observed with marginal loss in symmetry as Ra increases. The results are reported in the form of local and average Nusselt number on the heated floor. Correlations are developed to predict the heat transfer rates from the enclosure as a function of dimensionless heated width of the bottom wall and Ra, by least square linear regression analysis.     

Influence of geometrical factors and pressing mould wear on thermal-hydraulic characteristics for steel offset strip fins at low Reynolds number

Aiming at achieving a more comprehensive understanding of influence factors on thermal-hydraulic characteristics for high-pressure-direction type steel offset strip fins, this paper constructed a single fin core assembly test rig with lubricant oil as work media at low Reynolds number. Six fin schemes were experimentally investigated only varying in fin height and fin wavelength due to mould restrictions. Twenty fin schemes changing in fin width, fin angle, fin thickness and staggered fin wavelength were simulated for supplement, and the geometrical influences in fin performance were put forward. Both Taguchi method and uniform design were introduced to study the contribution of each geometrical factor to fin global thermal-hydraulic performance, verifying that fin wavelength and fin height have the most significant contributions. Based on signal to noise ratio distributions, fin geometries were optimized for 16% elevation of global performance at Reynolds number of 430, then the ‘cost-based fin performance’ was put forward and compared quantitatively, proving that above optimum fin scheme is also economical. Finally, mould wear influence in fin performance was tested in different wear periods of a vacuum heat-treated Cr12MoV mould pair, then three stages of initial wear, stable wear, and overdrive wear were defined based on pressing times. The influences were analyzed and regulations were deduced relating to mould pressing times and oil Reynolds number. The suggested lifetime for this type of mould pair is 1050 thousand pressing times. The paper intends for fin performance evaluation, optimization, and pressing mould improvement.     

Maximum useful energy-rate analysis of an endoreversible Joule–Brayton cogeneration cycle

Endoreversible Joule–Brayton cogeneration cycle has been optimized based on a new criterion, total useful energy-rate (including power output and useful heat output), and the efficiency at maximum total useful energy rate has also been determined. The effects of various cycle parameters on the maximum dimensionless total useful-energy rate and the efficiency at maximum total useful-energy rate have been assessed. Variations of dimensionless total useful-energy rate with respect to efficiency have also been analyzed. The reversible Joule–Brayton power cycle is a special case of the analyzed cycle.