超高层建筑烟囱效应和风压联合作用的机理与评估方法研究

The negative impacts of the stack effect are remarkable with rapid increasing of the super high-rise buildings both in number and in height, such as affecting elevator safety, wasting building energy and spreading air pollution etc. The complexity of the combined stack and wind effects is mainly caused by the wind exclusively. The infiltration mechanism of the combined stack and wind was investigated through exploring their respective effect, and the refined infiltration model was then built based on the theories of the fluid mechanics and wind engineering. The pressure differences between indoor and outdoor, the air infiltration, the height of the Neutral Pressure Level, the airflow path as well as the risk under extreme wind climate condition were numerically analyzed utilizing the multi-zone model and computational fluid dynamics (CFD) simulation simultaneously. The latest research findings from the computational wind engineering (CWE) were adopted to help improve the CFD accuracy. The experiments of the natural ventilation by wind loads of 8-10 scaled building models were performed in boundary layer wind tunnel. A synthesized evaluation method, which integrating the wind tunnel and the numerical simulation closely, was then established for the research of the combined stack and wind effects. Finally, the prevention and mitigation measures against the stack effect were proposed for optimizing the architecture scheme purpose. This topic will be helpful for improving the safety and scientific design of modern super high-rise building, as well as for the future revision of the technical code.

随着超高层建筑数量和高度的激增，与烟囱效应相关的负面影响日益突出，如影响电梯运行安全，增加建筑能耗，扩大污染物传播等。烟囱效应热压和风压联合作用问题的复杂性主要由风引起。本课题通过对烟囱效应和风压渗风模式的考察，研究二者联合作用下的渗风机理；基于流体力学和风工程原理，建立更精细的热压-风压联合作用渗风计算模型；采用多区网络模型和CFD数值模拟方法，模拟联合作用效应，分析室内外压差、空气渗透量、中和面高度、气流通道、极端风气候条件下的风险性等；利用计算风工程新成果以提高CFD数值模拟的精确度；采用大气边界层风洞模拟方法，进行8-10种典型超高层建筑缩尺模型风压通风试验，并建立基于风洞试验-数值模拟的热压和风压联合作用综合评估方法体系；研究防治和缓解联合作用不利效应的设计策略和技术措施，为优化建筑设计提供指导。本课题将有助于提升超高层建筑设计的安全性和科学性，为今后有关技术规范的修订提供参考。

烟囱效应是只在建成的实际超高层建筑中、在特定的季节发生的一种非受控室内外空气渗透现象，它主要和室内外温差、电梯井道的高程以及建筑的渗透特性有关。强烈的烟囱效应将导致电梯关闭故障、气动噪声超标、能源浪费，是当前超高层建筑都普遍面临的难题，而目前由于研究不足导致建筑设计规范和电梯产品设计中都对这一重要问题缺乏规定。本项目进行了超高层建筑烟囱效应的系统研究，首先建立分析超高层建筑烟囱效应的标准模型，采用多区域网路模型数值方法，系统探讨了室内外温差、室内空间分割、电梯井道设计、建筑构件渗风特性、风压作用等参数影响规律；其次，依托重大工程项目，联合物理风洞试验方法，结合常年气象统计数据，建立了新的评估超高层建筑烟囱效应-风压联合作用的概率分析方法，提高了数值模拟分析结果的合理性和准确性；再次，进行了真实电梯门机系统的风洞试验研究，获得了真实电梯厅门的风压特性分布规律，以及电梯门机系统在不同风压作用下的开闭运动机械性能表现、承压阈值等参数，为电梯产品设计及产品优化提供了参考；最后，对我国从南到北5座城市的10余栋超高层建筑烟囱效应进行了现场实测，获得了一批宝贵的超高层建筑烟囱效应风压分布特性的现场实测数据。本项目为今后完善技术规范、优化建筑设计以及提升电梯产品性能奠定了基础。