雨幕墙压力平衡效果影响因素分析及设计建议

Analysis of influence factors on pressure equalization and design suggestions for rain-screen walls

针对空间均匀分布风压作用下气屏刚性无渗漏压力平衡雨幕墙,通过赫姆霍兹共振方程的统计线性化以及窄带激励下的定性分析,获得风压激励下雨幕墙压力平衡效果受空腔区隔体积、雨幕开孔面积、开孔孔道中空气柱的有效长度、开孔孔道的流量系数、外部风压脉动量等参数的影响规律,并通过时域数值计算进行验证。研究结果表明:①雨幕开孔面积和孔道流量系数越大,或空腔区隔体积、孔道空气柱有效长度、外压脉动量越小,则由外部风压到雨幕两侧压差传递函数在低频段的幅值越小;在高频段的则与此相反;②孔道空气柱有效长度和外压脉动量越小,压差均方根越小;③为了达到较好的压力平衡效果,在雨幕墙设计中,应使雨幕上开孔面积与空腔区隔体积的比值尽可能大,同时要对共振加以留意,另外尽可能减小开孔深度。

For pressure-equilibrium rain-screen walls with rigid and no-leakage air-barriers loaded with spatially uniform wind, through statistical linearization of the Helmholtz resonator model and qualitative analysis for the case of narrowband load, the influences of parameters on the pressure equalization across the rain-screen are determined, which then are validated by using numerical simulations in the time domain. The study shows：①The amplitude of the transfer function of the net pressure decreases when the area of the rain-screen opening or the discharge coefficient of the opening increases, or the volume of the cavity compartment, the effective length of the air plug in the opening, the root-mean-square of the wind pressure decreases at low frequencies, while the opposite occurs at high frequencies;②The root-mean-square of the net pressure decreases with the decrease of the effective length of the air plug in the opening or the root-mean-square of the wind pressure;③For better pressure equalization, the ratio of the area of the opening to the volume of the compartment should be increased and depth of the openings in the rain-screen decreased, while attention is paid to resonance.