机械排烟系统补风量设计探讨
Discussion on design of make-up air rate of mechanical smoke exhaust systems
摘要：
排烟房间排烟和补风的质量流量相等，但温度不相等，且温度相差越大，排烟和补风的体积流量相差越大。目前工程实践中补风量普遍按照规范下限取排烟体积流量的50%进行设计，与排烟温度没有关系。根据GB 51251—2017《建筑防烟排烟系统技术标准》要求，高大空间（净高大于6 m）的烟层平均温度需要计算确定，并且可以通过改变储烟仓深度进行调整。通过计算可知，在不同组合工况下可以得到不同的排烟温度，此时补风占排烟体积流量的比例为45%~81%。
Abstract：
The mass flow rate of smoke exhaust and make-up air in the smoke exhaust room is equal, but the temperature is not equal, and the greater the temperature difference, the greater the difference between the volume flow rate of smoke exhaust and make-up air. At present, in engineering practice, the make-up air rate is generally designed according to 50% of the exhaust smoke volume flow rate at the lower limit of the specification, which has nothing to do with the exhaust smoke temperature. According to the requirements of GB 51251-2017 Technical standard for smoke management systems in buildings, the average temperature of smoke layer in the large space with a clear height of more than 6 m needs to be determined by calculation, and can be adjusted by changing the depth of the smoke storage bin. It can be seen from the calculation that different smoke exhaust temperatures can be obtained under different combinations of working conditions. At this time, the proportion of the make-up air rate to the exhaust volume flow rate is 45% to 81%.
Keywords:mechanical smoke exhaust system; average temperature of smoke; smoke exhaust rate; make-up air rate; heat release rate