隣接した円形断面急拡大・急縮小部を通る流れの損失係数

概要

論文の詳細を見る
A loss coefficient for a sudden expansion, based on the velocity v_1 in the smaller pipe, can be well approximated by Borda-Carnot's equation under the present experimental conditions, m≦0.4295 and R_<el>&elDot;(3~)×10^4, where m=(D_1/D_2)^2, the area ratio, and R_<el>=v_1D_1/v, the Reynolds number, and where D_1 and D_2 are the inner diameters of the smaller and the larger pipes respectively. Measurements of a loss coefficient ζ_c for a sudden contraction and a loss coefficient ζ for a sudden expansion and a sudden contraction closely placed with a distance L were made under the same conditions. The measured value of ζ_c was found to depend on R_<el> as well m. Meanwhile that of ζ increases linearly with L when L/D_2lE:2, regardless of m and R_<el>. The gradient dζ/dL gradually decreases with further increases in L, and ζ agrees well with the value calculated by neglecting the interaction between a sudden expansion and a sudden contraction when L_D_2≧. Empirical formulae for ζ_c and ζ are presented.
社団法人日本機械学会の論文
1986-09-25