超长电力隧道被遮挡固壁间接吸热效果分析

Indirect heat absorption effect of shielded solid wall of long underground power tunnel

为量化隧道被遮挡固壁间接吸热的效果,采用数值模拟的方法,研究超长隧道与土壤内部温度分布特征。结果表明,被遮挡固壁内部会形成明显的切向温度梯度,通过切向传热间接吸收隧道内空气中的热量,相当于将吸热面积增大15%~30%。为将间接吸热效应纳入隧道固壁吸热量的计算中,引入遮挡修正系数,并根据数值结果给出遮挡修正系数与隧道长度间的关联式,以便于工程实际中的应用。

A numerical investigation is conducted on the temperature distribution in a long electric power tunnel,and the indirectly heat transfer of the shielded solid wall is analyzed quantitatively.The results show that an evident tangential temperature gradient is observed inside the shielded solid walls.As a result,the shielded walls indirectly absorb the heat from the air,and this is equivalent to increasing the direct heat absorbing area by 15%to 30%.In order to include introduce the indirect heat transfer term into the calculation of the heat absorption by the solid materials surrounding the tunnel,a shield correction factor is introduced and a fitting equation for correlating the shield correction factor and tunnel length is determined by using the numerical results for practical applications.