Investigation of Flow in Truncated-Helicoidal-Ramp Dropshafts

研制了一种装有固定螺旋角螺旋叶片的吊杆。这些都会产生漩涡，并由此产生向内离心力的作用，使空气滞留在下垂轴流中。同时，叶片作为一个有效的、连续分布的摩擦源来耗散能量。竖井将市政地面排水系统中的收集元件连接到大型地下运输隧道。通风和能量消耗是关键要求。新设计将这两个功能有效地结合在一起。该项目是为了探索这种设计的变化情况下，非常深的落水竖井，其中必须限制能量消耗。这是通过只用叶片部分填充的轴来实现的，具有可变螺旋角的入口部分。这种构型中的流动结构和构型的优化将通过实验确定。还将开发一个简单的流动分析模型。该设计有可能消除非常大的除氧室和独立的能量消散器，从而导致更小和更经济的安装。

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.