Investigation of Flow in Truncated-Helicoidal-Ramp Dropshafts

一种装有固定螺旋角的螺旋叶片的下降轴， 开发 这些产生漩涡，并由此产生向内的漩涡， 在竖井流中夹带空气的影响。 同时， 叶片作为一个有效的，连续分布的来源， 摩擦来消耗能量。 升降轴连接收集元件 在市政地面排水系统中， 隧道 通风和能量耗散是关键要求。 新的设计有效地整合了这两个功能。 该项目 为了探索这种设计的变化， 必须限制能量耗散的竖井。 这是 完成轴只有部分充满叶片， 可变螺旋角入口段。 在这样的流动结构， 配置和配置的优化，将是 通过实验确定。 一个简单的流动分析模型 也将得到发展。 该设计具有以下潜力 消除了非常大的脱气室和单独的能量 分散器，导致更小，更经济 装置.

A dropshaft filled with helical vanes of fixed helix angle has been developed. These produce swirl and a resulting inward centrifuging effect for entrapped air in the dropshaft flow. Simultaneously, the vanes act as an effective, continuously distributed source of friction to dissipate energy. Dropshafts connect collection elements in municipal surface drainage systems to large underground conveyance tunnels. Air venting and energy dissipation are key requirements. The new design integrates both features effectively. The project is to explore a variation of this design for the case of very deep dropshafts in which energy dissipation must be limited. This is accomplished with shafts only partially filled with vanes, with a variable helix angle entrance section. The flow structure in such a configuration, and optimization of the configuration, will be determined experimentally. A simple analytical model of the flow will also be developed. The design holds the potential for elimination of very large deaeration chambers and separate energy dissipators, leading to much smaller and more economical installations.