The novel jet self-priming centrifugal pump,as important modern irrigation equipment,is widely used in large-scale irrigation,mine drainage and so on.In order to improve the profile streamline of blade,the inlet shape...The novel jet self-priming centrifugal pump,as important modern irrigation equipment,is widely used in large-scale irrigation,mine drainage and so on.In order to improve the profile streamline of blade,the inlet shape of impeller was designed as distorted and the outlet shape as cylindrical,which can not only improve the pump efficiency,but also shorten the self-priming time.Further,the novel jet self-priming system was proposed,by employing the jet nozzle and check valve to improve the velocity of self-priming.Meanwhile,nine different structure jet nozzles were designed based on the orthogonal design method,and the relevant self-priming experiments were performed on I level accuracy test bench in Jiangsu University.According to the greycorrelational analysis,the influence of the nozzle geometry parameters on the self-priming performance was obtained.The relationship between self-priming time and self-priming height was discussed.The test results showed that the hydraulic design of jet self-priming centrifugal pump was reasonable;all indicators met the Chinese national standard;the head reached 21.04 m and efficiency was 72.8%under the design flow condition.What is more,the self-priming performance was obviously improved by adjusting the geometrical parameters of nozzle.When the height of the self-priming process was 5.3 m,the self-priming time reached 62 s,which was much shorter than the national standard.Therefore,this research could provide reference for designing the structure of jet self-priming centrifugal pump.展开更多
Ornamental value of 45 ornamental grass resources was evaluated by grey-correlation analysis based on the full investigation and research of ornamental grass resources in Kunming and with the characters of ornamental ...Ornamental value of 45 ornamental grass resources was evaluated by grey-correlation analysis based on the full investigation and research of ornamental grass resources in Kunming and with the characters of ornamental value, height, color of leaf and inflorescence as evaluating indexes. The results showed that the correlation degree with ideal species of 34 in the 50 ornamental grasses was higher than 0.6; Saccharum fallax, Erianthus longisetosus, Erianthus rufipilus, Zizania latifolia, etc. had better ornamental effects and their correlation degree with ideal species were 0.863 6, 0.812 5, 0.900 0 and 0.815 5, they can be used for landscaping directly.展开更多
基金the support from the National Natural Science Foundation of China (No. 51979138, No.51609105, No.51679111, No.51409127 and No.51579118)China Postdoctoral Science Foundation (Grant No.2016M601738 and 2018T110458)+7 种基金Natural Science Foundation of Jiangsu Province (BE2016163, BRA2017353 and No.BK20161472)Six Talents Peak Project of Jiangsu Province (No. JNHB-CXTD-005)Jiangsu Province University Natural Sciences Foundation (Grant No. 16KJB570002)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)National Key R&D Program Project (No.2017YFC0403703)Open Foundation of National Research Center of Pumps (Grant No.NRCP201604)Graduate Student Scientific Research Innovation Projects of Jiangsu Province (Grant No. SJKY19_2547)Chinese Scholarship Council (CSC) for the financial support
文摘The novel jet self-priming centrifugal pump,as important modern irrigation equipment,is widely used in large-scale irrigation,mine drainage and so on.In order to improve the profile streamline of blade,the inlet shape of impeller was designed as distorted and the outlet shape as cylindrical,which can not only improve the pump efficiency,but also shorten the self-priming time.Further,the novel jet self-priming system was proposed,by employing the jet nozzle and check valve to improve the velocity of self-priming.Meanwhile,nine different structure jet nozzles were designed based on the orthogonal design method,and the relevant self-priming experiments were performed on I level accuracy test bench in Jiangsu University.According to the greycorrelational analysis,the influence of the nozzle geometry parameters on the self-priming performance was obtained.The relationship between self-priming time and self-priming height was discussed.The test results showed that the hydraulic design of jet self-priming centrifugal pump was reasonable;all indicators met the Chinese national standard;the head reached 21.04 m and efficiency was 72.8%under the design flow condition.What is more,the self-priming performance was obviously improved by adjusting the geometrical parameters of nozzle.When the height of the self-priming process was 5.3 m,the self-priming time reached 62 s,which was much shorter than the national standard.Therefore,this research could provide reference for designing the structure of jet self-priming centrifugal pump.
文摘Ornamental value of 45 ornamental grass resources was evaluated by grey-correlation analysis based on the full investigation and research of ornamental grass resources in Kunming and with the characters of ornamental value, height, color of leaf and inflorescence as evaluating indexes. The results showed that the correlation degree with ideal species of 34 in the 50 ornamental grasses was higher than 0.6; Saccharum fallax, Erianthus longisetosus, Erianthus rufipilus, Zizania latifolia, etc. had better ornamental effects and their correlation degree with ideal species were 0.863 6, 0.812 5, 0.900 0 and 0.815 5, they can be used for landscaping directly.
