纱窗对自然通风流量系数的影响

Effect of Insect Screens on the Discharge Coefficient of Natural Ventilation

我国住宅建筑普遍安装纱窗,会对自然通风的性能产生影响。为了研究纱窗对自然通风性能的影响,本文采用风洞实验测量了通过4种材料、孔隙率不同的纱窗的阻力流量特性,结合统计分析、数据计算等方法,得到安装纱窗后对于流量系数的影响并形成了相应的模型,通过实地测量验证了新模型的准确率在80%以上。研究结果表明:通过纱窗的流量系数与纱窗的孔隙率、厚度以及来流风速均相关,孔隙率越大、厚度越小、来流风速越大,则通过纱窗的流量系数越大。将新模型与文献中已有模型进行对比,发现新模型准确率提升了约34%,且采用新模型预测自然通风风速结果更加稳定。

Insect screens are always installed outside windows to prevent insects in most buildings in China.This in turn negatively impacts the natural ventilation performance.Small-scaled wind tunnel experiments were conducted in an environmental cabin to determine the effect of insect screens on natural ventilation performance.A combination of statistical analysis and data calculation was used to obtain the resistance characteristics of four different insect screens,and the effect of screens on ventilation rates were obtained via experiments.An insect screen resistance model was utilized to inspect the effect of porosity and validate field measurements.Furthermore,the accuracy of the precise model and simplified model exceeded 80%.The results indicated that the discharge coefficient of insect screens increases as the air velocity increases and finally tends to be constant.As the porosity increased,the discharge coefficient increased to a higher stable value because the air velocity increased.The accuracy of the new model improved by approximately 34%when compared with that of the model in the literature.