不同动力环境下孔间距对双孔射流特性的影响

发布时间：2018-05-17 09:32

本文选题：双孔射流 + 孔间距　；参考：《水利水电科技进展》2016年05期

【摘要】：为研究孔间距对双孔射流运动和稀释特性的影响,采用粒子图像测速技术(PIV)和激光诱导荧光技术(PLIF)分别对静水、横流和波浪环境下双孔射流的速度场和浓度场进行测量,对比分析了孔间距为5倍、10倍和15倍射流孔直径时双孔射流的轴向速度、横断面垂向速度、轨迹线及浓度场分布情况。结果表明:在静水环境下,孔间距较小时双孔射流的轴向速度衰减较单孔射流慢,随着孔间距的增大双孔射流轴向速度衰减的程度逐渐趋近于单孔射流。在横流环境下,随着孔间距的增大,前方射流对后方射流的遮掩作用不断减小,而后方对前方射流的卷吸作用也有所减弱,导致前方射流弯曲程度的增大和后方射流上升高度的降低。在波浪环境下,孔间距较小时,两孔中间存在一个独立的高浓度区;孔间距增大后,浓度等值线逐渐呈"凸"形分布。为降低双孔射流相互作用对射流初始稀释的影响,建议在波浪和横流环境下双孔射流的孔间距不宜小于射流孔直径的10倍。
[Abstract]:In order to study the effect of hole spacing on the motion and dilution characteristics of two-hole jet, particle image velocimetry (PIV) and laser-induced fluorescence technique (PLIFF) were used to measure the velocity field and concentration field of the two-hole jet in hydrostatic, cross-current and wave environments, respectively. The axial velocity, vertical velocity, trajectory and distribution of concentration field of the two-hole jet are compared and analyzed when the hole spacing is 5 times 10 times and 15 times the diameter of the jet. The results show that the axial velocity attenuation of the two-hole jet is slower than that of the single-hole jet when the hole spacing is small, and the attenuation degree of the axial velocity of the two-hole jet gradually approaches that of the single-hole jet with the increase of the hole spacing. In the crossflow environment, with the increase of hole spacing, the front jet mask to the rear jet decreases, and the front jet entrainment is also weakened. It leads to the increase of the bending degree of the front jet and the decrease of the rising height of the rear jet. In the wave environment, there is an independent high concentration region between the two holes when the hole spacing is small, and when the hole spacing increases, the concentration isoline gradually presents a "convex" distribution. In order to reduce the effect of the two-hole jet interaction on the initial dilution of the jet, it is suggested that the hole spacing of the two-hole jet should not be less than 10 times of the diameter of the jet in the environment of wave and cross flow.
【作者单位】：河海大学港口海岸与近海工程学院;
【基金】：国家自然科学基金(51379072) 高等学校博士学科点科研专项(20120094110016)
【分类号】：TV131

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