排序方式： 共有53条查询结果，搜索用时 15 毫秒
51.
基于对微网中分布式电源（DG）待选站址确定方法的分析,以微网的年费用最小为优化目标,建立了微网中DG选址定容的优化规划模型,综合考虑了DG及其负荷的时序特性、用户停电损失、购电成本、环保补贴等因素,全面衡量了微网在提高供电可靠性、实现清洁高效电能供应上的综合效益。将自适应离散粒子群优化算法应用于规划模型的求解中,得出了微网中DG的优化配置方案,并在Matlab中编程实现了规划模型及算法。在上海市某居民小区29节点微网中DG的优化配置应用中,验证了该模型及算法的有效性。 相似文献
52.
The flow field in a fuel cell is expected to distribute the reactants as uniformly as possible over the active plate, support the reasonable pressure drop across the channel and maximize the mass transfer through the catalyst layers. To simultaneously accomplish these requirements, an innovative multiple impingement jet flow field (MIJFF) is proposed in this study. A three-dimensional thermo-fluid simulation is used to evaluate the proposed idea and compare its performance against the commonly used parallel field flow (PFF). The domain of calculations includes a channel with multiple impingement jets linked to a porous gas diffusion layer under low Reynolds flow conditions. The results reveal that the suggested MIJFF design significantly increases the transport of the reactant gases through the catalyst layer. The penetration depth into the catalyst layer in the MIJFF arrangement is higher than that of the PFF setup and the use of the catalyst layer is optimized, which in turn can lead to a reduction of the activation drop. Compared to a PFF design under similar operating conditions, the mean Nusselt number is shown to increase by a factor of about 3.5 in the MIJFF setup. Furthermore, the temperature is more uniformly distributed in the MIJFF pattern which results in more effective distribution of the reactant gases over the active surface. The current study shows that under equal pressure drop conditions, the MIJFF exhibits a much higher performance than a PFF channel design. That is while the corresponding flow rate for the MIJFF is much lower than that of PFF. 相似文献
53.
ALI HASANABADI MAJID BANIASSADI KAREN ABRINIA MASOUD SAFDARI HAMID GARMESTANI 《Journal of microscopy》2016,264(3):384-393
Digital reconstruction of a complex heterogeneous media from the limited statistical information, mostly provided by different imaging techniques, is the key to the successful computational analysis of this important class of materials. In this study, a novel approach is presented for three‐dimensional (3D) reconstruction of a three‐phase microstructure from its statistical information provided by two‐dimensional (2D) cross‐sections. In this three‐step method, first two‐point correlation functions (TPCFs) are extracted from the cross‐section(s) using a spectral method suitable for the three‐phase media. In the next step, 3D TPCFs are approximated for all vectors in a representative volume element (RVE). Finally, the 3D microstructure is realized from the full‐set TPCFs obtained in the previous step, using a modified phase‐recovery algorithm. The method is generally applicable to any complex three‐phase media, here illustrated for an SOFC anode microstructure. The capabilities and shortcomings of the method are then investigated by performing a qualitative comparison between example cross‐sections obtained computationally and their experimental equivalents. Finally, it is shown that the method almost conserves key microstructural properties of the media including tortuosity, percolation and three‐phase boundary length (TPBL). 相似文献