粗糙度对水平热水浮射流影响特性研究

Influence of Roughness Height on Behavior of Hot Water Horizontal Buoyant Jets

采用物理实验和数值模拟方法,研究不同粗糙度的矩形断面明渠,横向水平浮射流特性;以期对浮射流和主流的相互作用、浮射流横向扩展规律、粗糙度对二次流强度的影响、粗糙度对浮射流横向扩展距离的影响有深入认识。为了更加充分验证分析的正确性,对动量方程进行简化,得到沿水深方向积分后的解析解;进而详细阐述粗糙度对二次流强度的影响。研究表明,随着粗糙度增加,横向水平浮射流扩展宽度减小;且随着排水口淹没水深减小,粗糙度对热水浮射流横向扩展宽度的影响不断减弱。不同粗糙度对二次流强度影响不同是造成上述现象的主要原因。该成果可用于不同粗糙度河槽的温排水问题的研究中。

The behavior of hot water horizontal jets in open rectangular channel with different roughness height has been experimentally and numerically studied, which aims to better understand the interaction of buoyant jets and main-stream, the rule of jet width, the impact of roughness height on secondary current intensity and jet width. In order to verify the analysis, an analytical solution to the simplification of momentum equation was presented which elaborate on the impact of roughness height on secondary current intensity. The research showed that increased jet width was promoted with the decreasing of roughness height. In addition, the influence of roughness height on jets width was obviously weakened with the decreasing of the submerged outfall depth. The secondary cur- rent intensity clearly accounts for this phenomenon. The research findings can be applied to thermal discharge into river channel with varying roughness height.