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分液冷凝器的管程理论设计及热力性能评价 被引量:7
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作者 陈二雄 陈颖 陈雪清 《制冷学报》 CAS CSCD 北大核心 2012年第6期19-25,共7页
根据分液冷凝器强化换热思想对其管程理论设计方法进行了研究。依据质量流速和干度来判断每一流程中制冷剂的流型,并依此选取Cavallini换热模型公式的方法求其平均换热系数,同时采用Cavallini两相压降模型和Darcy-Weisbach单相压降模型... 根据分液冷凝器强化换热思想对其管程理论设计方法进行了研究。依据质量流速和干度来判断每一流程中制冷剂的流型,并依此选取Cavallini换热模型公式的方法求其平均换热系数,同时采用Cavallini两相压降模型和Darcy-Weisbach单相压降模型分别确定冷凝区和过冷段的压降。针对一个案例计算了三种管程设计方案下冷凝器管内冷凝换热系数和端压值,并用惩罚因子PF对其综合热力性能进行了评价。计算结果表明:不同的管程设计方案中管内制冷剂的流量分配均匀性存在较大的差异,均匀性越好,其综合热力性能越优。在质量流速为1200~1500 kg/(m2.s)范围内,与同等换热面积的蛇形管冷凝器相比,其中最好的分液冷凝器的PF值减小了48.5%~54.1%,可见设计优良的分液冷凝器的综合热力性能明显优于蛇形管冷凝器。 展开更多
关键词 热工学 分液冷凝器 管程理论设计 换热系数 压降 惩罚因子
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Key Technologies of the Hydraulic Structures of the Three Gorges Project 被引量:6
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作者 马洪琪 迟福东 《Engineering》 SCIE EI 2016年第3期340-349,共10页
To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with... To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with its huge scale and comprehensive benefits,is extremely complicated,and the design difficulty is greater than that of any other hydro project in the world.A series of new design theories and methods have been proposed and applied in the design and research process.Many key technological problems regarding hydraulic structures have been overcome,such as a gravity dam with multi-layer large discharge orifices,a hydropower station of giant generating units,and a giant continual multi-step ship lock with a high water head. 展开更多
关键词 Three Gorges Project Large orifice gravity dam Penstock on dam downstream surface Tailrace tunnel with sloping ceiling Stable archFully lined ship lock
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