转笼式生物农药雾化喷头的性能试验

化学农药对生态环境的危害和人类健康的威胁使得低毒、低残留、不易产生抗药性的生物农药日益受到重视,但与之相配套的喷施机具的缺乏限制了生物农药的推广使用。为了研究保证生物农药存活率的专用喷施器械与操作方法,该文研究了喷施生物农药的专用转笼式离心喷头,并测试了其雾化性能和生物活性保持率。该文建立性能测试系统,利用粒子图像测速系统和激光粒度仪研究生物农药离心雾化喷头的转笼直径、丝网目数等结构参数,流量、转速等操作参数和生物农药制剂选择对于雾滴流场均匀性、雾滴粒径分布、生物农药活性的影响。量化分析了喷头结构和操作参数对雾滴体积中径和苏云金杆菌、白僵菌2种生物农药存活率的影响程度,采用SPSS软件通过相关信息和逐步回归分析建立了包含转笼直径、丝网目数、输药流量、转笼转速因素的转笼喷头雾化性能多元线性回归拟合模型,并检验其拟合度,通过实测数据对其进行验证发现该模型精度较高。综合各因素,提出了转笼式生物农药雾化喷头结构和操作参数的优化配置为:转笼直径100mm、丝网目数60、转笼转速3000r/min、输药流量80L/h。结果表明,转笼输液装置的双侧对称进液比单侧进液时雾滴流场均匀性提高,为了保证生物农药活性,转笼式喷头的转速不宜太高。该文的研究为设计生物农药喷施机具、制定确保活性成分的操作规范、提高生物农药防治病虫害效果提供了理论依据和技术支持。

Performance experiments of rotary cage atomizer for biological pesticide application

To combat plant pests and diseases, spraying pesticide is an efficient and timely control method. The increasing use of a wide range of toxic chemical pesticides deliberately released into the environment can cause important problems such as human health threats, bioaccumulation and pest resistance, and soil and groundwater pollution. In response to concerns about the effects of chemical pesticides on environments and human health, there have been significant interests in biological pesticide technology with low toxicity, less residue, and reduced pest resistance. Biopesticide technology is limited in real applications, due to the lack of appropriate sprayer and standard technology. In this paper, a rotary cage atomizer for biopesticide was developed. The influence of biopesticide atomizer structure (cage diameter and cage mesh number), operational parameters (flow rate and rotational speed), and liquid types (bacillus thuringiensis and beauveria bassiana) on atomization performance and biopesticide application efficacy was investigated using PIV and a Winner laser diffraction particle analyzer. The pattern of liquid inlet was fixed experimentally by the droplet's flow field uniformity. The impacts of individual factors on droplet size were analyzed using a T-test to eliminate inter-correlation among the variables of interest. A multiple linear regression model, which predicted the volume median diameters (VMD), was established. The model showed a high degree of correlation with the experimental results. The model took into account not only the cage diameter, but its number of cage meshes, the liquid flow rate, and rotational speed of the cage. Furthermore, a histogram and normal P-P plot of standardized residuals were used to assess the model's goodness-of-fit and the measured data were also analyzed to prove model fitness and feasibility. Finally, the optimal combination of biopesticide rotary atomizer structure and operational parameters was implemented. The results indicated that the cage atomizer's liquid inlet of bilateral symmetry is better than the unilateral pattern to improve the distribution uniformity of droplets. The rotational speed of the rotary cage atomizer should not be too high to maintain the viability and infectivity of biopesticides. Results from this paper provide a case study showing how to spray biopesticide to treat plant pests and diseases effectively by using proper sciences and technologies.