應用共軛梯度法精準控制公路隧道火災煙流之研究

Application of the Conjugate Gradient Method to Precisely Control the Smoke Flow in a Road Tunnel

張鴻明(Hong-Ming Jang) ； 何偉誌(W. C. Ho)

《華岡工程學報》 22期 (2008/06) Pp. 83-88

https://doi.org/10.29987/CCUHKJE.200806.0012

摘要

縱流式通風隧道發生火災時，煙熱沿隧道拱頂往上游回溯之距離與隧道風速息息相關。而當煙熱沿隧道流動需於中途由側面管道導向豎井排除時，在氣流轉彎處煙熱仍難免會部分繼續往下游前行，除非當地之風速與風向能被精準控制。本研究以泛用型計算流體力學軟體ANSYS CFX為基礎，計算隧道火災之流場與溫度場，並嘗試將其與共軛梯度法結合以期求取控制隧道火災煙熱回溯點之風速，以便進一步為複雜通風系統發展出可以精準控制煙流之方法。

關鍵字

隧道火災 ； 煙熱導流 ； 臨界風速

並列摘要

In a longitudinally ventilated tunnel, the backlayering effect induced by a fire depends primarily on the averaged wind speed near the fire. The effectiveness on detouring the smoke to exhaust shaft also depends on the averaged wind speed at the junction where smoke is detoured. In this study, a flow model set up using the commercial package ANSYS CFX is incorporated with the conjugate gradient method and proved to be able to determine the wind speed that can precisely control the smoke flow.

並列關鍵字

Tunnel fires ； Smoke-flow control ； Critical velocity