汪小珊, 严海军, 周凌九, 徐云成. SSQ系列射流施肥器水力性能试验研究[J]. 农业工程学报, 2020, 36(21): 31-38. DOI: 10.11975/j.issn.1002-6819.2020.21.004
    引用本文: 汪小珊, 严海军, 周凌九, 徐云成. SSQ系列射流施肥器水力性能试验研究[J]. 农业工程学报, 2020, 36(21): 31-38. DOI: 10.11975/j.issn.1002-6819.2020.21.004
    Wang Xiaoshan, Yan Haijun, Zhou Lingjiu, Xu Yuncheng. Experimental research of hydraulic performance on jet fertilizer applicator of SSQ series[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2020, 36(21): 31-38. DOI: 10.11975/j.issn.1002-6819.2020.21.004
    Citation: Wang Xiaoshan, Yan Haijun, Zhou Lingjiu, Xu Yuncheng. Experimental research of hydraulic performance on jet fertilizer applicator of SSQ series[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2020, 36(21): 31-38. DOI: 10.11975/j.issn.1002-6819.2020.21.004

    SSQ系列射流施肥器水力性能试验研究

    Experimental research of hydraulic performance on jet fertilizer applicator of SSQ series

    • 摘要: 基于农业生产中水肥一体化技术的施肥要求,该研究对国内常用的SSQ系列射流施肥器进行了性能测试。以吸肥量、进出口压差等指标为研究目标进行了施肥器水力性能的分析和预测,推导了SSQ系列射流施肥器开始吸肥和吸肥效率最高时进出口压差与进口压力的关系公式。结果表明:在正常工作阶段,SSQ系列射流施肥器的吸肥量随进出口压差的增加而增大,在空化条件下达到极限工况;8种不同规格施肥器在进口压力超过0.20 MPa时才能充分发挥吸肥性能;正常工作阶段临界压差与进口压力关系公式的斜率与试验值的误差小于15%,斜率的大小主要受喉管截面和喷嘴出口截面的面积比影响;效率最高时进出口压差与进口压力关系公式的斜率与试验值的平均相对误差为17%,验证了该关系公式的合理性。该文提出的SSQ系列射流施肥器水力性能预测公式可为同类产品的设计和应用提供参考。

       

      Abstract: Fertilizer device is essential to the precision fertigation technology. Most fertilizer equipment includes the pressuretanks, plunger pump of fertigation, Venturi injector, and self-pressure fertilizer device. A jet pump is widely used in theindustrial and agricultural production, because of its simple structure, and convenient operation without an external power. In the integration technology of water and fertilizer, the jet pump can serve as the function of Venturi injector. However, some jetfertilizer applicators with various types and sizes cannot meet the irrigation requirements of small pressure loss and large suction amount. In this study, 8 jet fertilizer applicators of SSQ series were tested according to the fertilization requirements of agricultural irrigationsystem, and subsequently their hydraulic performances were evaluated using the suction amount, and the pressuredifference between inlet and outlet. In terms of pressure difference, the working condition of a jet fertilizer applicator can be divided into 3 stages, including the no-injection, normal, and extreme stage. The results show that the suction amount of a jet fertilizer applicator increased with the increasing of pressure difference during the normal stage. The cavitation occurred, and the suction amount reached the maximum during the extreme stage. The 8 jet fertilizer applicators were achieved the optimal performance of injection, if the inlet pressure was higher than 0.20 MPa, where the maximum suction amount was found to be related to thecross-sectional area ratio of nozzle and throat. During the normal stage, the pressure difference of starting to inject or of themaximum efficiency was in positively linear relation with the inlet pressure. A theoretical linear equation with structural parameters was proposed to predict the relationship between pressure difference and inlet pressure, starting to inject, and the maximum efficiency, where most data derived from basic performance equation and pressure ratio, without considering theintercept. The slope mainly depended on the area ratio, and thereby it can be strongly related to the difference of pressure loss. In each inlet pressure, the maximum difference of pressure varied linearly with the increase of inlet pressure, where as, the cavitation was result in the large flow resistance during the extreme stage. The slope error of starting to inject was less than15%, and the average relative slope error of the maximum efficiency was 17% between regression model and relation formula, indicating that the relation formula had a good agreement with the experimental data. The prediction on thehydraulic performance of a jet fertilizer applicator can provide a sound theoretical basis for the design and application. Nevertheless, there were some assumptions when deriving this formula. It was assumed that the pressure was the same everywhere in thechamber between nozzle and throat. It also ignored the head loss in terms of the length of throat portion and diffuser portion. The derived relation formulas can be further improved in thefuture by considering the influences of extreme stage orcavitation.

       

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