Experimental Optimization of Jet Self-Priming Centrifugal Pump Based on Orthogonal Design and Grey-Correlational Method

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.

昆明地区主要观赏草资源及其观赏价值评价

1材料与方法1.1材料来源笔者在对云南省植物资源调查过程中发现,野生观赏草约有10科77属162种,重点对昆明地区野生观赏草进行了调查,参照相关资料进行了总结,得到的主要观赏草科属分类及观赏特性见表1(表见第57页Table1)。其中,多数为野生观赏草,包含部分已栽培种,如芦竹、虉草、滇蔗茅、菰、鸢尾等。1.2评价方法及标准采用灰色关联度分析法。