卜形岔管水力特性研究

Hydraulic characteristics of bifurcated pipes

提出在不改变分岔角角度的同时,通过设置直线倒角,以应对分岔角应力集中问题。通过数值模拟方法,研究了设置倒角的卜形岔管水力特性,具体对比分析了不同结构参数的圆弧形、直线倒角体型岔管汇流的水流流态、泄流能力和压强特性。结果表明,直线倒角体型岔管流场平顺,主流流向与支管轴线的一致性较好,而圆弧形倒角体型岔管的流场顺畅性相对较差;对于相同的倒角半径,直线倒角体型岔管的泄流能力优于圆弧形倒角体型岔管,且倒角半径越大,对泄流能力的影响越大,与无倒角时相比,直线倒角与圆弧形倒角体型岔管泄流量最大降幅分别为0.5%、6.8%;直线倒角体型岔管压强分布特征与无倒角体型岔管较为接近,但圆弧形倒角体型岔管与之有明显区别,存在局部低压区。

Stress concentration phenomenon can be addressed by setting a linear-chamfer angle at the bifurcation,given the certain bifurcation angle.In the present work,the hydraulic characteristics of roundchamfered and linear-chamfered bifurcated pipes are numerically investigated,including the flow behaviors,discharge capacity,and characteristics of pressure distribution,with different geometric conditions considered.The results show that in a linear-chamfered pipe,the flow is smooth and its mainstream is in a direction largely along the branch pipe axis,while a round-chamfered pipe shows rather intricate flow patterns.Compared to that without a chamfered angle,the maximum relative declines in discharge capacity are 0.5%and 6.8%for linear-and round-chamfered pipes,respectively;the discharge capacity of a linear-chamfered pipe is greater.The pressure distribution behavior changes little when the pipe is linear-chamfered,but it become significantly different when round-chamfered.