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Performance of water-jet pump under acceleration
Wu Xian-Fang,Li Ming-Hui,Liu Houlin,Tan Minggao,Lu You-Dong 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1
The instantaneous acceleration affects the performance of the water-jet pump obviously. Here, based on the user-defined function, the method to simulate the inner flow in water-jet pumps under acceleration conditions was established. The effects of two different acceleration modes (linear acceleration and exponential acceleration) and three kinds of different acceleration time (0.5s, 1s and 2s) on the performance of the water-jet pump were analyzed. The results show that the thrust and the pressure pulsation under exponential acceleration are lower than that under linear acceleration at the same time; the vapor volume fraction in the impeller under linear acceleration is 27.3% higher than that under exponential acceleration. As the acceleration time increases, the thrust gradually increases and the pressure pulsation amplitude at the impeller inlet and outlet gradually decreases, while the law of pressure pulsation is the opposite at the diffuser outlet. The main frequency of pressure pulsation at the impeller outlet is different under different acceleration time. The research results can provide some reference for the optimal design of water-jet pumps.
Purification of naphthalene from eutectic mixture by continuous column crystallization
Zhengming Yi,Qunsheng Li,Xufeng Sun,Minggao Su 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.2
To obtain highly purified naphthalene, a column crystallizer was employed and operated in the continuous multistage countercurrent fractional mode. The principles and characteristics of the process are introduced. A large amount of experimental work has been done on the crystallization process in a D=50 mm×1,350 mm column. The effects of operation conditions including the composition of feed, reflux ratio, stirring speed and the bed height of crystal on crystallization were systematically studied. The experiments showed that over 99.0% of the purity of product can be easily achieved in such conditions: feed composition among w=85.462-95.894%, reflux ratio among 1.42-4.04,the crystal bed height among 400-900 mm. The purity of product even reaches 99.996% in experiment.
Ming Gao,Lei Yang,Chunhua Zhang,Wen Guan,Ailing Li 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.3
With the prevalence of ubiquitous computing, big data, and Internet of things in cloud computing environment, it’s important to consider both of collaboration, heterogeneity, isolation of multi-tenant applications and information security and privacy in service composition. Current methods need to be readdressed to cope with cross-organizational, multi-roles participated and knowledge-intensive service composition in an integrated way. Based on the modeling and verification theories of hierarchical colored petri-net, a resource-oriented collaborative workflow model, its resource control model and the joint modeling and verification method are proposed which present a unified solution bridging the gap between traditional structure-oriented workflow execution model and resource-oriented workflow domain model taking into account the underlying roles, tasks, resources and their association and coordination in design-time and runtime as well. In our approach, a business process is divided into three layers: the backbone top-level process, the task fulfillment sub-process and the task execution sub-process in order to reduce the complexity of model verification. In addition this paper gives in-depth discussions on the fine control of implicit parallel and multi-threaded process executions. Finally, the case studies show that the proposed methods are not only applicable to modeling and verification of traditional task-oriented workflows, but also suited for knowledge or data-intensive workflows which involve