Optimization Strategy And Software Implementation Of Greenhouse Multi-environmental Factors Considering Spatio-temporal Variation Characteristics

As a semi closed ecosystem,greenhouse can reduce the constraints and dependence of traditional agriculture by the external environment,but its self-regulation ability is limited.The advantages and disadvantages of the internal environment have a significant impact on crop growth,pest control,energy conservation and emission reduction.Using advanced modeling and optimization technology,reasonable control and optimization of greenhouse environment can effectively improve crop growth conditions,promote crop yield and save energy consumption,which has important practical significance and practical application value for promoting the further development of facility agriculture.In this paper,considering the spatiotemporal variability of greenhouse environment,the computational fluid dynamics(CFD)model of greenhouse is constructed,and the non-dominated genetic algorithm with elitist strategy(NSGA-II)is combined to establish the C++-Fluent joint optimization framework;Aiming at the time-consuming problem of CFD iterative optimization,the optimization scheme of greenhouse environment was designed based on supercomputer to realize the high-resolution and efficient optimization of multiple environmental factors in greenhouse,and provide the basis for the selection of greenhouse environmental parameters suitable for crop growth.The main research contents are as follows:(1)The characteristics of light,temperature,humidity and air flow inside and outside the greenhouse were analyzed,and the appropriate control equations and calculation models were established;The steady-state simulation of greenhouse environment system is carried out by CFD software,and the experimental data under the same conditions are compared with the simulation results to verify the validity and rationality of the established greenhouse CFD model,which provides model support for multi parameter optimization of Venlo type glass greenhouse.(2)In order to optimize the crop growth environment and save greenhouse energy consumption,a multi environmental factors optimization framework considering the spatial-temporal variability of greenhouse was established.Among them,the wet curtain temperature and negative pressure fan speed of greenhouse are set as control variables,and the temperature field of crop area,carbon dioxide distribution and energy consumption of greenhouse fan are set as optimization objectives;NSGA-II multi-objective optimization algorithm is written in C + +language,and the data interaction in CFD iterative optimization is realized through the text user interface(TUI)function of fluent.According to the temporal and spatial variation characteristics of greenhouse environmental parameters,the typical period was selected for optimization simulation experiment.The steady-state simulation of the greenhouse environment model is carried out by using the optimal solution set,and the optimization effect of the proposed framework is verified.(3)Aiming at the time-consuming problem of CFD iterative optimization,the "Shenwei · Taihu Lake light" supercomputer was further used to realize the multi-objective optimization scheme of greenhouse environment.The temperature field,velocity field and carbon dioxide distribution in greenhouse were optimized efficiently by supercomputer combined with multi-objective optimization algorithm.Compared with personal computer,the computing efficiency is greatly improved,and the computing time is shortened by about 88.09%.(4)In order to meet the operation and improvement of facility agricultural technicians,the optimization software of greenhouse multi environmental factors was developed.The dos and windows interfaces can be used in different environments,and the algorithm interface is convenient to update and optimize the algorithm.