Simulation and Optimization of Energy Efficiency and Total Enthalpy Analysis of Sand Based Packed Bed Solar Thermal Energy Storage

This study is focused on the simulation and optimization of packed-bed solar thermal energy storage by using sand as a storage material and hot-water is used as a heat transfer fluid and storage as well.The analysis has been done by using the COMSOL multi-physics software and used to compute an optimization charging time of the storage.Parameters that control this optimization are storage height,storage diameter,heat transfer fluid flow rate,and sand bed particle size.The result of COMSOL multi-physics optimized thermal storage has been validated with Taguchi method.Accordingly,the optimized parameters of storage are:storage height of 1.4m,storage diameter of 0.4 m,flow rate of 0.02 kg/s,and sand particle size 12 mm.Among these parameters,the storage diameter result is the highest influenced optimized parameter of the thermal storage fromthe ANOVA analysis.For nominal packed bed thermal storage,the charging time needed to attain about 520 K temperature is more than 3500 s,while it needs only about 2000 s for the optimized storage which is very significant difference.Average charging energy efficiency of the optimized is greater than the nominal and previous concrete-based storage by 13.7%,and 13.1%,respectively in the charging time of 2700 s.

基于Taguchi法的表面式永磁同步电机多目标优化

以一台8极48槽的表面式永磁同步电机为例,针对表面式永磁同步电机的特点,选取电机的齿槽转矩、效率和磁钢用量为优化目标,选取极弧系数、不等厚磁极偏心距、磁极厚度和气隙长度为优化参数。利用ANSYS Maxwell的参数化扫描法与Taguchi法相结合的方法对电机进行多目标优化设计,实验并分析得到优化后的最佳参数组合。有限元仿真结果表明,采用上述方法,电机的齿槽转矩减小,效率提高,磁钢用量减小,实现了多目标同时优化。

面贴式永磁同步电动机的弱磁特性优化

针对面贴式永磁同步电动机的特点,选择电机的槽型参数H_(s2),B_(s0)和永磁体厚度hm以及极弧系数α_p这4个参数作为初选变量,对电动机的性能进行优化,使得电动机在获得较大弱磁扩速倍数的同时又具有较高的效率。优化过程中首先采用田口参数优化方法对电机进行多目标优化设计,分析参数变化时电机性能指标的变化趋势,其次对于影响趋势显著的变量进一步采用响应曲面方法,设计以弱磁扩速倍数、效率为响应的实验,得到最终的优化结果。仿真结果验证了上述方法的有效性和正确性。