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为了提高对塑料连栋温室环境的认识水平,必需研究连栋塑料温室各种通风机构的通风性能和通风率。因此,通过运用气体浓度衰减示踪技术,研究了连栋塑料温室中卷膜通风系统和天窗开启式系统的通风性能,确定了模拟通风率的相关系数。研究表明,在试验条件下,当通风口完全打开时,卷膜通风系统比天窗开启式具有可高达2.32倍的通风率;在风速为3m/s时,位于拱顶脊部的通风口比位于拱底部的通风率大60%;在同样条件下,防虫网可把通风率减少18%～22%。研究还发现,它们在相似的开启程度变化过程中,通风率的变化趋势也有显著的差异。另外,为简化研究,引入了描述通风系统结构性能的流量系数Cd和风力影响系数Cw。在实验条件下,以风力为主导通风时Cd和Cw的相关参量C的参考值对天窗开启式系统为0.178,对卷膜通风式系统为0.318;而在以温度为主导通风时Cd的参考值对天窗开启式系统为0.667,对卷膜通风式系统为0.863。
In order to improve the level of awareness of the plastic greenhouse environment, it is necessary to study the ventilation performance and ventilation rate of various ventilation mechanisms in the multi-span plastic greenhouse. Therefore, by using the gas concentration attenuation tracing technique, the ventilation performance of the coiled plastic ventilation system and sunroof open system in a multi-span plastic greenhouse was studied and the correlation coefficient of the simulation ventilation rate was determined. The results show that under the experimental conditions, when the vents are fully opened, the membrane ventilation system has a ventilation rate as high as 2.32 times higher than that of the skylight opening. When the wind speed is 3m / s, The ventilation rate at the bottom of the arch is 60% greater; under the same conditions, the insect net can reduce the ventilation rate by 18% ~ 22%. The study also found that there was also a significant difference in the trend of ventilation rates during similar changes in the opening degree. In addition, to simplify the research, the flow coefficient Cd and the wind influence coefficient Cw, which describe the performance of the ventilation system, were introduced. Under the experimental conditions, the reference value of the relevant parameter C of Cd and Cw for wind-driven ventilation is 0.178 for the sunroof opening system and 0.318 for the rolling-film ventilation system; while the reference value of Cd for wind-driven ventilation 0.667 for sunroof opening system and 0.863 for roll-wound ventilation system.