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Influence of Diffuser Vane Number on Energy Loss of Multistage Centrifugal Pump
Tian Xin Wu,Deng Hao Wu,Ting Zhang,Hai Ming Huang,Yue Zhong Wu,Jie Gang Mou 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.4
As a key component of a multistage pump, the diffuser affects the efficiency of the multistage centrifugal pump. However, the loss mechanism inside the diffuser and links between the loss mechanism and vane numbers of diffuser were still not fully understood. In order to investigate the influence of the number of diffuser vane on the energy loss characteristics of multistage centrifugal pump, this paper analyzes the energy loss characteristics of pump with different number of diffuser vane by utilizing entropy production theory. The results show that under the design condition, when the number of diffuser vane increases to 11, the head is increased by 1.2m and the efficiency is increased by 3%. At the same time, with the increase of the number of diffuser vane, the backflow and eddy phenomena are gradually weakened, flow stream is more stable, the entropy production rate is significantly reduced, but the intensity of pressure pulsation in the diffuser is increased slightly.
Effect of meridional shape on performance of axial-flow fan
Xin Chen,Linlin Cao,Peng Yan,Peng Wu,Dazhuan Wu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.11
In this study, the effect of impeller meridional shape on the performance of axial-flow fan is investigated by CFD method. Three axialflow fan impellers with different meridional shapes are designed. The blade angle, blade stacking condition and other structure factors of the impellers are all remained consistent. The performance curves of the three impellers are calculated and compared. In almost all the interested flowrate range, the impeller W3 with an inverted-isosceles-trapezoid meridional shape and the longer blade camber achieves both the higher pressure rise and the higher efficiency than the other two impellers. A two-stage axial-flow fan designed on basis of W3 is manufactured and tested. Test results show good agreement with the calculated performance curves. Further, analyses of the CFD results are conducted to reveal the reasons for the different performance. A newly-defined Local Euler head (LEH) is introduced to represent the distribution of the major Euler work in the axial-flow fan. And the LEH distributions in the three impellers are obtained. W3 achieves the highest LEH at blade Trailing edge (TE), because it could perform the most Euler work to the fluid with the longest blade camber. Then losses in the impellers are analyzed by means of the entropy generation. Among the losses in impeller, the tip leakage loss and endwall friction loss are dominated at design flowrate. The generation condition of the tip leakage loss shows significant differences among the three impellers. And the whole power loss in impeller of W3 is slightly higher than those of the other two models. However, the power loss difference among the three impellers is negligible. And due to the highest shaft power, the efficiency loss of W3 is the lowest of all.
Xin Wu,Yibing Liu,Rui Liu,Li Zhao 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.4
The occurrence of surge in a centrifugal compressor results in large oscillations in pressure and flow. To avoid damaging the compressor because of surge, we develop several surge detection methods in this study. Considering the incipient surge phenomenon, the Empirical mode decomposition (EMD) and the Morlet Continuous wavelet transform (CWT) methods are selected. Both methods are validated through experimental data collected from surge tests conducted on the three-stage Ingersoll-Rand Centac centrifugal compressor at Toyota Motor Manufacturing in Kentucky, USA. For incipient surge detection, the EMD-based method can determine the threshold 1 sec earlier than the Morlet CWT-based method. Therefore, the EMD method can be used to implement the incipient surge detection scheme on the tested centrifugal compressor for safety considerations.
Wu-Xin Yun 한국수자원학회 2003 한국수자원학회논문집 Vol.36 No.1
시화 조력발전소용으로는 벌브식 수차발전기가 가장 경제적인 수차형식이다. 본 고에서는, 하얼빈 전기기기 제작(주)의 수력발전 기기 설계를 포함한 전반적인 사항을 제안한다. 예비적으로 시화 조력발전소에 적용 가능한 벌브형 수차발전기에 대한 주요 인자와 일반적인 사항을 기술하고자 한다.
MDS Coded Caching for Device-to-Device Content Sharing Against Eavesdropping
( Xin Shi ),( Dan Wu ),( Meng Wang ),( Lianxin Yang ),( Yan Wu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.9
In this paper, we put forward a delay-aware secure maximum distance separable (MDS) coded caching scheme to resist the eavesdropping attacks for device-to-device (D2D) content sharing by combining MDS coding with distributed caching. In particular, we define the average system delay to show the potential coupling of delay-content awareness, and learn the secure constraints to ensure that randomly distributed eavesdroppers cannot obtain enough encoded packets to recover their desired contents. Accordingly, we model such a caching problem as an optimization problem to minimize the average system delay with secure constraints and simplify it to its convex relaxation. Then we develop a delay-aware secure MDS coded caching algorithm to obtain the optimal caching policy. Extensive numerical results are provided to demonstrate the excellent performance of our proposed algorithm. Compared with the random coded caching scheme, uniform coded caching scheme and popularity based coded caching scheme, our proposed scheme has 3.7%, 3.3% and 0.7% performance gains, respectively.
Xin Wu,Yibing Liu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10
The failure of the hydraulic Inlet guide vane (IGV) system needs to be avoided in the gas turbine compressor, since the IGV system is critical for the function and efficiency of the gas turbine and its fault can even cause the gas turbine to jump off the power grid. This paper investigates the detection of external and internal leakages, whose levels can be represented through corresponding leakage coefficients, at the cylinder in the hydraulic IGV system. Based on the dynamic model, we propose the recursive ridge regression parameter estimation method to detect and isolate different leakage coefficients under varying load. The developed algorithm is verified through experiments in a hydraulic IGV emulator. Based on experimental results, the proposed scheme can estimate leakage coefficients with good performance.
Identification of novel rheumatoid arthritis-associated MiRNA-204-5p from plasma exosomes
Wu Long-Fei,Zhang Qin,Mo Xing-Bo,Lin Jun,Wu Yang-Lin,Lu Xin,He Pei,Wu Jian,Guo Yu-Fan,Wang Ming-Jun,Ren Wen-Yan,Deng Hong-Wen,Lei Shu-Feng,Deng Fei-Yan 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Rheumatoid arthritis (RA) is an autoimmune disease characterized by infiltration of immune cells in the synovium. However, the crosstalk of immune cells and synovial fibroblasts is still largely unknown. Here, global miRNA screening in plasma exosomes was carried out with a custom microarray (RA patients vs. healthy controls = 9:9). A total of 14 exosomal miRNAs were abnormally expressed in the RA patients. Then, downregulated expression of exosomal miR-204-5p was confirmed in both the replication (RA patients vs. healthy controls = 30:30) and validation groups (RA patients vs. healthy controls = 56:60). Similar to the findings obtained in humans, a decreased abundance of exosomal miR-204-5p was observed in mice with collagen-induced arthritis (CIA). Furthermore, Spearman correlation analysis indicated that plasma exosomal miR-204-5p expression was inversely correlated with disease parameters of RA patients, such as rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. In vitro, our data showed that human T lymphocytes released exosomes containing large amounts of miR-204-5p, which can be transferred into synovial fibroblasts, inhibiting cell proliferation. Overexpression of miR-204-5p in synovial fibroblasts suppressed synovial fibroblast activation by targeting genes related to cell proliferation and invasion. In vivo assays found that administration of lentiviruses expressing miR-204-5p markedly alleviated the disease progression of the mice with CIA. Collectively, this study identified a novel RA-associated plasma exosomal miRNA-204-5p that mediates the communication between immune cells and synovial fibroblasts and can be used as a potential biomarker for RA diagnosis and treatment.
Wu, Qiang,Zhao, Yi-Bing,Sun, Zhi-Hua,Ni, Jing,Wu, Yu-Zhong,Shao, Heng-Hua,Qu, Jun-Wei,Huang, Xin-En Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12
Aim: To examine lymph nodes obtained after lipolysis and liposuction of subcutaneous fat of the inguinal region of female vulvar cancer patients to explore the feasibility of clinical application. Methods: The field of operation was on the basis of the range of the conventional resection of inguinal lymph nodes. We injected lipolysis liquid fanwise, started liposuction after 15-20 minutes; then the subcutaneous fatty tissue was sucked out clearly by suction tube. We selected the first puncture holes located on 2-3 cm part below anterior superior spine, the others respectively being located 3cm and 6cm below the first for puncturing into the skin, imbedding a trocar to intorduce $CO_2$ gas and the specular body, and excise the lymph nodes by ultrasonic scalpel. The surgical field chamber was set with negative pressure drainage and was pressured with a soft saline bag after surgery. Results: A lacuna emerged from subcutaneous of the inguinal region after lipolysis and liposuction, with a wide fascia easily exposed at the bottom where lymph nodes could be readily excised. The number of lymph nodes of ten patients excised within the inguinal region on each side was 4-18. The excised average number of lymph nodes was 11 when we had mature technology. Conclusion: Most of adipose tissue was removed after lipolysis and liposuction of subcutaneous tissue of inguinal region, so that the included lymph nodes were exposed and easy to excise by endoscope. This surgery avoided the large incision of regular surgery of inguinal region, the results indicating that this approach is feasible and safe for used as an alternative technology.