隧道施工环境中有限空间附壁射流的试验研究

目的是研究在隧道施工中限空间附壁射流运动的规律，通过大量的试验并结合理论分析，得出如下结论：在有限空间内，附壁射流的流动区域可分３部分：附壁射流区、回流区和涡流区；有限空间附壁射流边界近似为直线，射流扩散角约为７．６７、；在射流的初始段和主体段流动都具有相似性；有限空间附壁射流的断面最大速度沿程衰减，且比半无限空间内衰减得快；有限空间附壁射流回流区第度随风管出口流量的增加而增长，并给出了计算公式。

Experimental Study on the Wall Jet in Defined Space during Tunnel Construction

The purpose of this paper is to study the wall jet in defined space during tunnel construction. For two dimensional wall jets in defined space, through a lot of experiments and theoretical analyses it is concluded that: (1) the flow field of wall jet in defined space can be categorized as the wall jet zone, the back flow zone and the eddy zone; (2) the boundary of a wall jet can be approximately regarded as a straight line and the angle of spread is 7.67 degrees; (3) the flow motions in the developing region and fully developed region of the flow are similar; and (4) along the distance, the maximum velocity of profile decays faster in defined space than that in half limitless space; and the length of the back flow zone in a defined space wall jet increases with the increase of the pipe flow. In this paper, the formula for calculating the length of the back flow zone is presented.