分叉隧道合流段流动特征及局部损失特性研究
Study on the Flow Characteristics and Local Loss Characteristics of the Confluence Segment of Bifurcate Tunnel
陈泽恩 1陈小峰 2孔祥苗 3张欣 4张永强 5刁岳峰 6吴珂2
作者信息
- 1. 浙江大学平衡建筑研究中心,杭州 310007;浙江省海洋岩土工程与材料重点实验室,杭州 310058
- 2. 浙江大学平衡建筑研究中心,杭州 310007;浙江省海洋岩土工程与材料重点实验室,杭州 310058;浙江大学中原研究院,郑州 450000
- 3. 宁海县公路与运输管理中心,宁波 315600
- 4. 西安石油大学电子工程学院,西安 710065
- 5. 浙江省海洋岩土工程与材料重点实验室,杭州 310058
- 6. 浙江大学平衡建筑研究中心,杭州 310007
- 折叠
摘要
进口匝道的存在导致隧道内空气出现合流现象,掌握合流段空气的流动特征和损失特性是分叉隧道通风设计的基础.针对夹角为5°～15°的分叉隧道,采用CFD方法和比尺模型试验研究合流比q和夹角θ对合流段空气流动和局部损失的影响.结果表明:随着q增大,主线局部损失系数ξ21迅速减小,而匝道局部损失系数ξ31则先迅速增大后趋于稳定.当合流前主线与匝道风量比Q大于两者截面积比φ时,ξ21主要受流线弯曲的影响,ξ31主要受射流增压作用的影响;当Q<φ时,ξ21和ξ31的主控因素则互换.在q较小时,ξ21、ξ31基本不随合流夹角θ变化;在q较大时,随着θ增大ξ21基本保持不变,而ξ31减小.提出了可准确预测夹角为5°～15°分叉隧道合流段局部损失系数的半经验公式,弥补了分叉隧道合流通风设计理论的不足.
Abstract
Presence of entrance ramp will lead to air confluence in the tunnel,so understanding the flow characteris-tics and loss characteristics of air in the confluence segment is a prerequisite for ventilation design of a bifurcate tun-nel.For a bifurcate tunnel with 5°～15°included angle,the CFD method and scale model are used in the experimen-tal study on how the confluence ratio q and included angle θ will impact the air flow and local loss in the confluence segment.As the results indicate:As q increases,the local loss coefficient ξ21 of the main line quickly decreases,while the local loss coefficient ξ31 of the ramp first increases quickly and then stabilizes.Before confluence,if the air volume ratio Q between the main line and ramp is greater than the sectional area ratio φ between them,ξ21 is mainly affected by the flow line bending,and ξ31 is mainly affected by the jet flow pressurization;if Q<φ,the main control-ling factors of ξ21 and ξ31 are interchanged.If q is small,ξ21 and ξ31 will essentially remain unchanged even when the confluence included angle θ changes;if q is big,then as θ increases,ξ21 essentially remains unchanged,while ξ31 de-creases.A semi-empirical formula is proposed that can accurately predict the local loss coefficient of the confluence segment of a bifurcate tunnel with 5°～15°included angle.This formula fills the gap in the design theory for confluence ventilation of bifurcate tunnel.
关键词
分叉隧道/合流段/CFD/比尺模型试验/局部损失/预测模型Key words
Bifurcate tunnel/Confluence segment/CFD/Scale model test/Local loss/Prediction model引用本文复制引用
基金项目
陕西省自然科学基础研究计划(2023-JC-YB-378)
宁波市交通运输科技项目(202113)
出版年
2024
NETL
NSTL
万方数据