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本文通过实验方法研究了环形套管和外迷宫结构的阻力特性,并与文献进行了比较,以期得到适合于大压差流道中使用的节流件结构形式和计算方法。 对于环形套管,我们在雷诺数Re=3×10~3—3×10~4范围内,D_内/D_外=0.831和0.985条件下进行了实验。实验证明,其摩阻系数可按布劳修斯公式进行计算,其误差在实验误差范围内,而与文献推荐的计算公式偏差较大。 对于外迷宫,是在雷诺数Re=5×10~3—4×10~4的范围内进行实验的。在迷宫间隙δ_0不变时,实验证明t/s≈0.25时,迷宫的阻力系数达到最大值,和文献[1]的结论一致;在t/s<0.25时,实验值与理论计算值吻合;而在t/s>0.25时,需要引入一个修正系数C。在迷宫的t/s保持一定的条件下,随着缝隙δ_0的增加,迷宫的阻力系数呈线性下降。 在本实验范围内,迷宫偏心对阻力系数的影响可以忽略不计。
In this paper, the resistance characteristics of annular casing and external labyrinth structure are studied by experimental method and compared with the literature, in order to obtain the structure and calculation method of throttling member suitable for large differential pressure channel. For the annular casing, we conducted the experiment under Reynolds number Re = 3 × 10 ~ 3-3 × 10 ~ 4, D_ / D_external = 0.831 and 0.985. Experiments show that the friction coefficient can be calculated according to the Bratisius formula, the error is within the experimental error range, and the deviation from the recommended formula in the literature is large. For the outer maze, the Reynolds number is Re = 5 × 10 ~ 3-4 × 10 ~ 4 range of experiments. When the labyrinth gap δ_0 is constant, the experimental results show that the drag coefficient of the labyrinth reaches the maximum at t / s≈0.25, which is consistent with that of the literature [1]. The experimental results agree well with the theoretical ones at t / s <0.25. In the case of t / s> 0.25, a correction factor C needs to be introduced. In the maze of t / s to maintain a certain condition, with the gap δ_0 increases, the resistance coefficient of the maze decreased linearly. Within the scope of this experiment, the influence of the maze eccentricity on the drag coefficient can be neglected.