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- 저자 : Xinping Zeng (검색결과 3 건)
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Numerical investigation on the recirculation in annular jet pumps
Longzhou Xiao,Xinping LONG,Xiaohong Li,Qinglong Zeng,Xuelong Yang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6
The flow within the annular jet pump (AJP), in some degree, resembles the annular wall jet developing in a pipe with great axial pressure gradient. In some working conditions, there exists the backflow near the centerline. However this differs from the case in a center jet pump (CJP) that the recirculation emerges near the inner wall of the throat. The recirculation in AJP affects a lot to its performance, especially when AJP is utilized to convey something alive, such as fish. This paper aims to numerically study the impact of two parameters, the flow ratio M and the area ratio A, on the location, size and formation of the recirculation in AJP. After being validated by the experimental results, the RNG k-ε turbulent model was adopted. It is found that: (1) As M increases, the width and height of the recirculation in AJP decreases, and the separation point of the recirculation shifts gradually far away from the nozzle exit while the reattachment point slightly moves; (2) As A becomes larger, the width and height of the recirculation enlarged, with M keeping constant; (3) For AJP with constant A, the recirculation emerges when M declines to a critical value, and the value varies linearly with A; (4) The Craya-Curtet number Ct and the momentum ratio J, which take A and M into whole consideration, are also feasible in describing the disappearance of the recirculation. However the critical value of Ct and J are different from that discovered in CJP. The critical Ct increases with decreasing A and the critical momentum ratio Jc experiences a linear relationship with A.
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Wenwei Tang,Xinping Zeng,Yusheng Zhao,Guoqing Ye,Wenchi Gui,Yaming Ni 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4
A study was carried out on the disinfection efficiency of electrolyzed oxidizing water (EOW) on spores of Bacillus subtilis var. niger. The results showed a remarkable fungicidal rate of 100% after 20 min duration of 191mg/L active available chlorine (ACC). The disinfection effect was improved with increased ACC or prolonged disinfection time, while organic interferents exerted a strong concentration-dependent inhibition against the disinfection. The disinfection mechanism was also investigated at bio-molecular level. EOW decreased dehydrogenase activity, intensified membrane permeability,elevated suspension conductivity, and caused leakage of intracellular K+, proteins, and DNA, indicating a damage of cell walls and membranes. Effects of EOW on microbiological ultra-structures were also verified by transmission electronic microscopy (TEM) images,showing that EOW destroyed protective barriers of the microbe and imposed some damages upon the nucleus area.
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Implementation of design of experiment for structural optimization of annular jet pumps
Qiao Lyu,Zhihuai Xiao,Qinlong Zeng,Longzhou Xiao,Xinping LONG 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2
The DOE (Design of experiments) method together with CFD (Computational fluid dynamics) was applied to optimize structural combination of the Annular jet pumps (AJPs). An AJP with an area ratio of 1.75 was selected as the simulation prototype and the numerical results were validated by experiments. According to the DOE method, four impact factors were selected for simulation. The results showed that two-factor’s reciprocal action is more applicable than that of single factor on the AJP’s performance, especially the two groups ,α*l t and l t *β, respectively. The structure of AJPs with different area ratios ranging from 1.5 to 40 were optimized by the DOE method. The corresponding optimum structural parameters and performance curves were plotted to acquire the performance envelope lines, the efficiency envelope line and the peak efficiency lines, which are useful for AJP’s structure design and obtaining its operation condition.
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