射流混药装置二维和三维流场对比分析

Contrast and analysis between 2D and 3D flow field of jet-mixing apparatus

为了探索射流混药装置的设计方法和试验方法,从数值模拟和试验研究两方面对射流混药内部流场进行了对比分析.建立了射流混药装置的三维模型,且将射流混药装置侧向农药入口等效为环向入口建立了其二维轴对称模型,分别确定了二维轴对称流场和三维流场的数值模拟方案,采用CFD软件Fluent对其流场进行了数值计算,并比较了二维轴对称模型与三维模型完成计算的CPU时间,结果表明二维轴对称模型比三维模型的计算效率高64%.搭建了混药试验台,测量了射流混药装置流动性能参数.试验研究的测量结果与数值模拟方案的计算结果对比确证表明:二维轴对称模型数值计算结果与实测值的最大偏差和平均偏差分别为7.41%和4.14%;三维模型数值计算结果与实测值的最大偏差和平均偏差分别为5.13%和3.41%,这表明确定的射流混药装置二维轴对称模型和三维模型的数值模拟方案均可用于工程计算.

Aimed at investigating the design method and test method of jet-mixing apparatus,numerical simulation and experiment research were both used to investigate the internal flow field of jet-mixing apparatus.In the numerical simulation,3D model of jet mixing apparatus were established. With no consideration of the internal flow field in the near suction pipe,2D axisymmetric model was also established,and then numerical simulation scheme for both 2D axisymmetric model and 3D model flow interior field were set up.Numerical investigation for their interior flow field were performed with CFD software Fluent.It is found that compare to 3D model,the 2D axisymmetric model can save 64% CPU time for the same case.In the experiment research,mixing test bench was constructed,and performance parameters of jet-mixing apparatus were recorded.The experimental data were used to validate the numerical data.Results show that the simulated results and experiment results agree well with each other.The average relative deviation was 4.14%,and maximum relative deviation was 7.41% for 2D axisymmetric model.The average relative deviation was 3.41% and maximum relative deviation was 5.13% for 3D model.The established models can be used in engineering calculations.