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Ning Zhang,Minguan Yang,Bo Gao,Zhong Li,Dan Ni 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10
This study experimentally and numerically investigates the unsteady flow in a centrifugal pump with special slope volute under variousconditions to illustrate the detailed flow structures and pressure pulsation within the model pump. Whole flow passage is consideredduring the numerical simulation; pressure pulsation signals are extracted using nine fast-response pressure transducers. The Root meansquare (RMS) method is introduced to deal with the discrete components at fBPF of the different monitoring points along the volute casing,which is an effective attempt to evaluate the overall pulsating level of the model pump. Results show that numerical method canpredict the components at fBPF effectively; however, it has limited ability in capturing noise frequencies motivated by unsteady separateflow and non-linear interaction effect. Around the nominal flow rate, the predicted amplitudes at fBPF agree well with the experimentalresults, showing larger difference at the off-design conditions. To predict the pulsating level of the components at fBPF, two fitted equationsof the RMS values versus the flow rate and specific speed are carried out, which would be very helpful in evaluating the pressurepulsation level in the centrifugal pump.
Yongchao Zhang,Minguan Yang,Dan Ni,Ning Zhang,Bo Gao 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.3
Understanding of turbulent flow in the reactor coolant pump (RCP) is a premise of the optimal design ofthe RCP. Flow structures in the RCP, in view of the specially devised spherical casing, are more complicatedthan those associated with conventional pumps. Hitherto, knowledge of the flow characteristics ofthe RCP has been far from sufficient. Research into the nonintrusive measurement of the internal flow ofthe RCP has rarely been reported. In the present study, flow measurement using particle imagevelocimetry is implemented to reveal flow features of the RCP model. Velocity and vorticity distributionsin the diffuser and spherical casing are obtained. The results illuminate the complexity of the flows in theRCP. Near the lower end of the discharge nozzle, three-dimensional swirling flows and flow separationare evident. In the diffuser, the imparity of the velocity profile with respect to different axial crosssections is verified, and the velocity increases gradually from the shroud to the hub. In the casing, velocitydistribution is nonuniform over the circumferential direction. Vortices shed consistently from thediffuser blade trailing edge. The experimental results lend sound support for the optimal design of theRCP and provide validation of relevant numerical algorithms.
MIN GUAN,HAI-PENG BI,ZUYUAN WANG,SHAOHUA BU,LING HUANG,LI YANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.5
Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.