基于非平衡热模拟的粮糟摊晾工艺优化

Study of grain spreading and cooling process based on non equilibrium thermal simulation

[目的]提高粮糟摊晾温度控制的自动化程度。[方法]采用SST k-ω湍流模型及粮糟非热平衡模型进行理论分析,利用Fluent软件仿真运算并结合工艺验证,探究粮糟摊晾过程中的温度场分布规律,并对摊晾工艺进行优化。以摊晾完出料温度符合工艺要求的程度为评价标准,分析粮糟层厚度、板链行进速度以及排风量对空气流动分布、温度场分布及粮糟在整个行进过程中的温度变化情况。[结果]经过分析,料层厚度对摊晾出料温度存在显著影响,板链行进速度以及排风量的影响次之,分别确定了出料温度对粮糟处理量和排风量的关系式,便于工艺变更时的出料温度预测。[结论]经工艺验证,非平衡热模拟方法对摊晾过程仿真准确有效。该摊晾机最佳的工艺条件为粮糟摊晾厚度20 cm,板链行进速度0.150 m/s,排风量5000 m^(3)/h。

[Objective]To improve the automation level of 0the temperature control of grain cooling.[Methods]Using SST k-ωturbulence model and non-equilibrium thermal model to conduct theoretical analysis.Fluent was used for simulation and combined with process validation to explore the temperature distribution law during the process of grain spreading and cooling,and to optimize the spreading and cooling process via Univariate analysis and multivariate orthogonal analysis.Based on the degree how the discharge temperature meets the process requirements,and analyzed the impact of the thickness of the grain layer,the speed of the plate chain movement,and the impact of the exhaust air volume on the air flow distribution,temperature field distribution,and the temperature changes during the entire grain movement process.[Results]After analysis,it was found that the thickness of the material layer has significant impact on the discharge temperature,the speed of the plate chain movement and the exhaust air volume have secondary impacts.The relationship equations between the discharge temperature and the grain residue processing capacity,and exhaust air volume were determined,which were convenient for predicting the discharge temperature in case of process changes.[Conclusion]Through process verification,the non-equilibrium thermal simulation method is accurate and effective in simulating the spreading and cooling process.The optimal process conditions for this spreading and cooling machine are about 20 cm in thickness of grain,0.15 m/s in plate chain movement and 5000 m^(3)/h exhaust air volume.