日光温室后墙蓄热降低了通风降温效率,高温会刺激植物水分蒸腾,降低水资源利用率.本文以北京市通州区日光温室为研究对象,在原有的上、下通风口基础上,增设后墙通风口.基于DO辐射模型、组分输运模型和多孔介质模型建立了日光温室的计算流体力学(CFD)模型,探究了不同通风方式下温室微环境状况,并结合作物蒸腾模型分析获得了作物蒸腾特征.结果表明,气温变化会直接影响作物蒸腾强度,两者空间分布特征一致.中午温室高温,开启后墙、下通风口,较原来开启上、下通风口,气流走向相似,因减少部分蓄热墙体,降温效率提高5.7％,蒸腾量下降0.020 mm/h,开启后墙、上、下通风口,蒸腾量较原来下降0.005 mm/h.开启后墙、上通风口,由于两通风口靠近一侧且距离作物较远,只能形成北侧局部降温,降温效率下降10.3％,除湿效率较原来提高5.7％,蒸腾量升高0.035 mm/h.此外,在通风口组合中,将靠下的通风口设置在迎风方向,可减少外界来风能量、动量损失,以提高通风降温效率.研究结果可为日光温室微环境调节提供参考.
The heat storage of back wall of the solar greenhouse reduces efficiency of ventilation and cooling.High temperature will stimulate plant water transpiration and reduce the utilization rate of water resources.Taking Beijing Tongzhou solar greenhouse as the research object,on the basis of the original upper and lower vents,the rear wall vents were added.Based on DO radiation model,component transport model and porous medium model,a computational fluid dynamics(CFD)model of solar greenhouse was established.The microenvironment of greenhouse under different ventilation modes was explored,and the transpiration characteristics of crops were obtained by combining crop transpiration model analysis.The results showed that the change of temperature would directly affect the intensity of crop transpiration,and the spatial distribution characteristics of the two were consistent.The high temperature of the greenhouse at noon,the opening of the back wall and the lower vent,compared with the original opening of the upper and lower vent,the airflow trend was similar,due to the reduction of part of the heat storage wall,the cooling efficiency was increased by 5.7％,and the transpiration was decreased by 0.020 mm/h,the opening of the back wall,the upper and lower vent,the transpiration was decreased by 0.005 mm/h.After opening the back wall and the upper vent,because the two vents were close to one side and far away from the crop,only the north side can be partially cooled,the cooling efficiency was reduced by 10.3％,the dehumidification efficiency was increased by 5.7％,and the transpiration was increased by 0.035 mm/h.In addition,in the combination of vents,the lower vent was set in the windward direction,which can reduce the energy and momentum loss of the external wind and improve the ventilation cooling efficiency.The results provided a reference for the regulation of microenvironment in solar greenhouse.
万敏;杨魏;刘竹青;徐晨曦;刘东
中国农业大学水利与土木工程学院,北京 100083
园艺学与植物营养学
日光温室微环境;计算流体力学;通风方式;作物蒸腾
solar greenhouse microenvironment;computational fluid dynamics;ventilation mode;crop transpiration
《农业机械学报》 2024 (001)
328-338,349 / 12
国家自然科学基金项目(52179093)
10.6041/j.issn.1000-1298.2024.01.031
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