寒区公路隧道消防管道放水保温模式优化研究

寒区公路隧道消防系统保温关系着隧道运营消防安全。为了优化寒区隧道消防管道放水保温方案，建立了管道保温计算模型，根据传热学原理，采用多工况对比优化分析的方法，分别计算了消防主管和消防支管的放水时间和放水量，并确定了合适的保温层厚度；运用ANSYS软件对消防支管在无保温层和确定保温层厚度下进行了管道温度模拟分析。结果表明: 保温层越厚保温效果越好，但厚度达到一定值时，保温效果增长不明显，其厚度合适取值为0.06～0.08 m；环境温度和保温层厚度相同时，消防系统不冻，消防主管控制着放水量，消防支管控制着放水时间，应遵循“消防支管勤放水，消防主管控制放水量”的原则；数值模拟结果验证了消防支管在0.08 m保温层时，间隔8 h放水能够满足管道不冻的要求。结果可为寒区隧道消防管道保温设计提供依据。

Optimization of Thermal Insulation Mode with Water Releasing for Fire Fighting Water-supply Pipeline of Highway Tunnels in Cold Regions

The thermal insulation of fire fighting system is very important for safe operation of highway tunnel in cold regions. In this paper, the calculation model of fire fighting water supply pipeline insulation is established, and the volume of water released of trunk fire fighting water supply pipeline and water releasing time of branch fire fighting water supply pipeline are calculated by means of analysis based on heat transfer theory. Then the thermal insulation layer thickness is determined, and the temperatures of branch fire fighting water supply pipeline without thermal insulation layer and that with a specific thickness of thermal insulation layer are numerically simulated by means of ANSYS software. The results show that: 1) The thermal insulating effect improves as the thickness of thermal insulation layer increases. The rational thermal insulation thickness is 0.06 m to 0.08 m. 2) The volume of water released is dominated by the trunk fire fighting water supply pipeline and the water releasing time is governed by the branch fire fighting water supply pipeline under a specific ambient temperature and a specific thermal insulation layer thickness. The principle of “water released frequently by branch fire fighting water supply pipeline and volume of water released controlled by trunk fire fighting water supply pipeline” has to be followed. 3) The numerical results show that the requirement of fire fighting water supply pipeline can be met when the thermal insulation layer thickness reaches 0.08 m and interval time among water releasing reaches 8 h. The paper can provide reference for thermal insulation design of fire fighting water supply pipeline of tunnels in cold regions.