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RISS 인기검색어
- 검색키워드
- 저자 : Hongwu Zhu (검색결과 5 건)
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Yi Shi,Hongwu Zhu,Binbin Yin,Ruiting Xu,Jiate Zhang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4
Multiphase pump is a cost-effective option for subsea oil and gas field development. The ability to handle different inlet gas volume fractions (GVFs) especially high inlet GVF is critical to the development of pump performance. In this study, the two-phase flow characteristics in normal impeller and split vane impeller at different inlet GVFs were investigated by steady numerical simulations. The gas distribution on blade-to-blade plane and meridional flow channel at different inlet GVFs were analyzed and compared. Gas accumulation area and movement characteristics of the gas-liquid flow in impeller flow passage were also pointed out by unsteady simulations. Experimental results of the pump differential pressure were compared with the numerical simulation results, to validate the accuracy of numerical simulation method. The flow characteristics in pump with modified impeller and its performance at different inlet GVFs were both compared with that of the normal impeller. The steady simulation results of normal impeller in different inlet GVFs show that gas concentrating area in the flow passage increases as inlet GVF grows. The unsteady simulation results indicate that gas pocket firstly occurs on the pressure side of impeller, then moves to the suction side in the middle area of blade and finally transfers to outlet of impeller and disappears. The errors between numerical simulation results and experiment data are below 10 %, which validated the feasibility of the numerical simulation method. Simulation results on the split vane impeller demonstrate that the gas accumulation area in flow passage of the modified impeller is dramatically decreased compared to that of the normal impeller. The performance of the modified impeller is generally better than the normal impeller especially in high inlet GVF conditions.
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Numerical investigation of heat transfer characteristics for Subsea Xmas tree assembly
Biao Hu,Hongwu Zhu,Kuang Ding,Fangling Xu,Youjiang Zhang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11
This study focuses on the heat transfer characteristic of a horizontal subsea Xmas tree assembly at a high spatial resolution. Computationalfluid dynamics (steady Reynolds-averaged Navier-Stokes) in combination with Low Reynolds number modelling (LRNM) isadopted for heat transfer analysis, which has been validated against a full scale underwater gate valve heat transfer experiment with goodagreements. The characteristics of cold sea water flowing through the subsea tree, and of convection heat transfer between the subsea treeand ambient cold water are obtained. The typical “hot spots,” which have high Convection heat transfer coefficient (CHTC) and creategreat large amounts of heat loss, are numerically determined. Under the designed water depth, the effects of installation orientation, seawater velocity, and inner oil temperature on convection heat transfer are investigated as well. Such work is significant for thermal designof the subsea tree to increase structural reliability and flow assurance level.
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Expanding Ring Search Energy Analysis and Optimization for Wireless Sensor Networks
Xiuxiu Wen,Huiqiang Wang,Guangsheng Feng,Hongwu Lv,Junyu Lin,Qiang Zhu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.9
Expanding Ring Search (ERS) is an advanced flooding technique exploring for targets progressively. It is widely used to locate destinations or information in wireless sensor networks. In this paper, a fundamental problem concerning the best ERS strategy to minimize energy cost in wireless sensor networks is addressed. We propose a model for estimating the average energy cost of ERS strategies, and a model for comparing the energy cost of an ERS strategy with pure flooding. The second model is then used to prove that incremental ERS strategies are inefficient in large-scale wireless sensor networks. Furthermore, we propose an ERS strategy optimization algorithm SSetOpt, which can be applied to both dense wireless sensor networks and sparse ones. The simulation results show that the strategy obtained by SSetOpt can cost 5% less energy than prior works when the network is sparse, say, the average degree is less than 30..
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Full-phase optimization of PDC bit cutter layout to reduce lateral force based on zoning method
Tong Cao,Kaian Yu,Xuyue Chen,Hongwu Zhu,Rui Zhang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
Balancing lateral force is essential to reduce bit vibrations and prolong bit service life. During the process of cutting, the instantaneous cutting situation is governed by the previous blades cutting. This paper introduces a notion called “zoning method” based on the cutting geometry of bit-rock interface, which is dedicated to distinguishing different phases of cutting. Furthermore, a full-phase optimization model is developed to optimize cutter layout for minimizing the lateral force in each cutting phase, the NSGA-II is used to solve for the Paretooptimal solutions, and the fuzzy comprehensive evaluation method is used to select the optimal solution. Finally, a case study of full-phase optimization of PDC bit cutter layout is conducted to highlight the advantage of the zoning method. The case study results show that the lateral force is reduced significantly in each cutting phase by using zoning method, which can help to achieve the real lateral force balance of PDC bit.
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HMFS : A Hybrid Message Ferrying Scheme for Clustered Opportunistic Networks
Zhang Yushu,Wang Huiqiang,LV Hongwu,Feng Guangsheng,Zhu Jinmei 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.4
Opportunistic network is an evolution of MANETs to delivery messages in intermittent-ly connected or completely disconnected wireless networks. Message ferrying is an effec-tive routing mode in opportunistic networks. However, the single message ferry routing scheme leads a much higher delay as the increasing of the network scale, comparing with that in small scale opportunistic networks. It has been proved that multiple message fer-ries routing scheme can improve the performance of large scale networks, but the prob-lems of synchronization and coordinate between ferries have a bad effect on the routing efficiency. To solve these problems, a Hybrid Message Ferrying Scheme (HMFS) for clus-tered opportunistic networks is proposed. In HMFS, we divide the communication area into multiple regions based on clustering results and several cross zones containing the regions. A local ferry is deployed in each region to deliver messages in the region, and several global ferries are deployed according to horizontal and vertical zones to commu-nicate among the regions. Moreover, each region has a ferry relay node in it, which is used to orchestrate the local ferry and global ferries. Through the theoretical analysis and simulation results, we can see that HMFS can improve the effect of routing in oppor-tunistic networks in terms of network latency and delivery ratio.
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