构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,...构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,创建动态能源集线器(Dynamic Energy Hub,DEH)模型,建立各设备模型及目标函数,提出考虑设备变工况特性的RIES优化调度方法;其次,通过K-means聚类的方法表征源荷不确定性,并获得典型系统运行场景;最后,结合DEH模型,确定最优调度方案及各能源转换设备的容量配置结果。优化结果表明,所提方法可以对区域综合能源系统多类能源进行合理调度,提升系统运行经济性和可再生能源消纳能力,减少碳排放。展开更多
Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it ...Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coemcients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils （like CDAs）, slotted blades or other boundary layer control methods has helped the de- signers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade＇s suction side. Also, in compari- son to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.展开更多
文摘构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,创建动态能源集线器(Dynamic Energy Hub,DEH)模型,建立各设备模型及目标函数,提出考虑设备变工况特性的RIES优化调度方法;其次,通过K-means聚类的方法表征源荷不确定性,并获得典型系统运行场景;最后,结合DEH模型,确定最优调度方案及各能源转换设备的容量配置结果。优化结果表明,所提方法可以对区域综合能源系统多类能源进行合理调度,提升系统运行经济性和可再生能源消纳能力,减少碳排放。
文摘Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coemcients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils （like CDAs）, slotted blades or other boundary layer control methods has helped the de- signers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade＇s suction side. Also, in compari- son to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.
