海底隧道腐蚀环境下射流风机升压力衰减机理及计算方法研究

Research on jet-fan lift attenuation mechanism and calculation method in corrosive environment of undersea road tunnel

海底道路隧道内高湿度、富盐雾和多酸性气体的环境特征会加速腐蚀风机,进而使通风效果无法满足洞内环境控制标准。以厦门翔安海底隧道为依托对隧道内风机升压力展开现场测试,结合理论分析和Fluent滑移网格模型研究风机升压力计算公式和表面粗糙度与风机升压力的衰减关系。研究结果表明:单台射流风机升压力计算公式还应考虑风机自身性能损失折减系数η_(1);海底隧道腐蚀环境通过积垢沉淀、侵蚀和腐蚀效应增大风机叶片和流通部件的表面粗糙度,进而增大风流阻力,降低风机升压力;通过数值模拟得到基于表面粗糙度的风机升压力计算方法。研究结果揭示海底隧道腐蚀环境下风机升压力衰减机理并建立了计算方法,为同类型海底隧道通风系统设计提供参考。

The high-humidity,salt-rich spray and acid gas environment in urban undersea road tunnels may accelerate the corrosion of jet fans,so that the ventilation effect may not meet the environment control standards in tunnel.Based on the Xiang’an undersea tunnel in Xiamen,the field measurement of pressure lift produced by jet fan in the tunnel was carried out.By referring to theoretical analysis and Fluent dynamic grid numerical model,the calculation formula of jet fan pressure lift and the attenuation relationship between surface roughness and jet fan pressure lift were studied.The results show that in the calculation formula of a single jet fan pressure lift,the performance loss reduction coefficientη_(1)shall also be considered.The corrosion environment in undersea road tunnel may increase the surface roughness of the jet fan blades and the flow-through components due to the effects of accumulation and sedimentation,erosion and corrosion,which may further increase the air flow resistance and reduce the pressure lift.The calculation method of jet fan pressure lift based on surface roughness was obtained through numerical simulation.Based on the research results,the mechanism of reducing pressure lift by jet fan corrosion in urban undersea road tunnel can be revealed and furthermore a calculation method is established,which provides reference for the design of the same type of tunnel ventilation system.