粒子群优化(PSO)算法是一种新兴的群体智能优化技术,由于其原理简单、参数少、效果好等优点已经广泛应用于求解各类复杂优化问题.而影响该算法收敛速度和精度的2个主要因素是粒子个体极值与全局极值的更新方式.通过分析粒子的飞行轨迹...粒子群优化(PSO)算法是一种新兴的群体智能优化技术,由于其原理简单、参数少、效果好等优点已经广泛应用于求解各类复杂优化问题.而影响该算法收敛速度和精度的2个主要因素是粒子个体极值与全局极值的更新方式.通过分析粒子的飞行轨迹和引入广义中心粒子和狭义中心粒子,提出双中心粒子群优化(double center particle swarm optimization,DCPSO)算法,在不增加算法复杂度条件下对粒子的个体极值和全局极值更新方式进行更新,从而改善了算法的收敛速度和精度.采用Rosenbrock和Rastrigrin等6个经典测试函数,按照固定迭达次数和固定时间长度运行2种方式进行测试,验证了新算法的可行性和有效性.展开更多
为了克服差分进化算法寻优精度低、收敛速度慢、稳定性差等不足,提出一种基于多变异策略的自适应差分进化算法(ADE-MM)。首先,在3个变异策略的选择过程中添加2个具有学习功能的扰动阈值,以提高种群多样性,扩大搜索范围;然后,根据上次迭...为了克服差分进化算法寻优精度低、收敛速度慢、稳定性差等不足,提出一种基于多变异策略的自适应差分进化算法(ADE-MM)。首先,在3个变异策略的选择过程中添加2个具有学习功能的扰动阈值,以提高种群多样性,扩大搜索范围;然后,根据上次迭代的成功参数自适应调整当前参数,提高寻优精度和寻优速度;最后,利用向量粒子池法和中心粒子法产生新的向量粒子,进一步提高寻优效果。使用8个函数、5种对比算法(RMDE、OLCPDE、JADE、Sa DE、MDE_pBX)进行测试,且每种例子都独立执行30次。ADE-MM算法在均值和方差的比较中取得了全胜,其中在30维的情况下取得了5个独立胜利,3个并列胜利;在50维的情况下取得了6个独立胜利,2个并列胜利;在100维的情况下全部为独立胜利。同时在Wilcoxon rank sum test、胜率和算法耗时分析中,ADE-MM算法也取得优异的表现。实验结果表明,相对于其他5种对比算法,ADE-MM算法具有更强的全局寻优能力、收敛性和稳定性。展开更多
The characteristics of swirler flow field, including cold flow field and combustion flow field, in gas tur- bine combustor with two-stage swirler are studied by using particle image velocimetry （PIV）. Velocity compo...The characteristics of swirler flow field, including cold flow field and combustion flow field, in gas tur- bine combustor with two-stage swirler are studied by using particle image velocimetry （PIV）. Velocity compo- nents, fluctuation velocity, Reynolds stress and recirculation zone length are obtained, respectively. Influences of geometric parameter of primary hole, arrangement of primary hole, inlet air temperature, first-stage swirler an- gle and fuel/air ratio on flow field are investigated, respectively. The experimental results reveal that the primary recirculation zone lengths of combustion flow field are shorter than those of cold flow field, and the primary reeir- culation zone lengths decrease with the increase of inlet air temperature and fuel/air ratio. The change of the geo- metric parameter of primary hole casts an important influence on the swirler flow field in two-stage swirler com- bustor.展开更多
文摘粒子群优化(PSO)算法是一种新兴的群体智能优化技术,由于其原理简单、参数少、效果好等优点已经广泛应用于求解各类复杂优化问题.而影响该算法收敛速度和精度的2个主要因素是粒子个体极值与全局极值的更新方式.通过分析粒子的飞行轨迹和引入广义中心粒子和狭义中心粒子,提出双中心粒子群优化(double center particle swarm optimization,DCPSO)算法,在不增加算法复杂度条件下对粒子的个体极值和全局极值更新方式进行更新,从而改善了算法的收敛速度和精度.采用Rosenbrock和Rastrigrin等6个经典测试函数,按照固定迭达次数和固定时间长度运行2种方式进行测试,验证了新算法的可行性和有效性.
文摘为了克服差分进化算法寻优精度低、收敛速度慢、稳定性差等不足,提出一种基于多变异策略的自适应差分进化算法(ADE-MM)。首先,在3个变异策略的选择过程中添加2个具有学习功能的扰动阈值,以提高种群多样性,扩大搜索范围;然后,根据上次迭代的成功参数自适应调整当前参数,提高寻优精度和寻优速度;最后,利用向量粒子池法和中心粒子法产生新的向量粒子,进一步提高寻优效果。使用8个函数、5种对比算法(RMDE、OLCPDE、JADE、Sa DE、MDE_pBX)进行测试,且每种例子都独立执行30次。ADE-MM算法在均值和方差的比较中取得了全胜,其中在30维的情况下取得了5个独立胜利,3个并列胜利;在50维的情况下取得了6个独立胜利,2个并列胜利;在100维的情况下全部为独立胜利。同时在Wilcoxon rank sum test、胜率和算法耗时分析中,ADE-MM算法也取得优异的表现。实验结果表明,相对于其他5种对比算法,ADE-MM算法具有更强的全局寻优能力、收敛性和稳定性。
基金Supported by the National Natural Science Foundation of China(50906040)the Nanjing University of Aeronautics and Astronautics Research Funding(NZ2012107,NS2010052)~~
文摘The characteristics of swirler flow field, including cold flow field and combustion flow field, in gas tur- bine combustor with two-stage swirler are studied by using particle image velocimetry （PIV）. Velocity compo- nents, fluctuation velocity, Reynolds stress and recirculation zone length are obtained, respectively. Influences of geometric parameter of primary hole, arrangement of primary hole, inlet air temperature, first-stage swirler an- gle and fuel/air ratio on flow field are investigated, respectively. The experimental results reveal that the primary recirculation zone lengths of combustion flow field are shorter than those of cold flow field, and the primary reeir- culation zone lengths decrease with the increase of inlet air temperature and fuel/air ratio. The change of the geo- metric parameter of primary hole casts an important influence on the swirler flow field in two-stage swirler com- bustor.
