變曲率彎道超臨界流水面超高及壓強特性研究

STUDY ON THE SUPERELEVATION AND PRESSURE OF SUPERCRITICAL FLOW IN VARIABLE CURVATURE BEND

丁燦(Can Ding) ； 王韋(Wei Wang) ； 田忠(Zhong Tian) ； 張春妮(Chun Ni Zhang)

《中國土木水利工程學刊》 29卷4期 (2017/12) Pp. 249-256

https://doi.org/10.6652/JoCICHE.201712_29(4).0004

摘要

針對超臨界流條件下彎道水流水面超高大、壓強分佈不均等問題，本文提出了變曲率彎道，通過與定曲率彎道的對比試驗，對彎道段流態、水深、水面超高及時均壓強進行了系統研究，並在相應條件下利用fluent軟體對變曲率彎道進行了數值模擬。結果表明：變曲率彎道水流流態更平穩，邊牆對水流的約束作用明顯減小，更少出現凸岸河床露底現象，彎道中最大水面超高較定曲率彎道最多減小15.1%。時均壓強分佈也更均勻，各工況下變曲率彎道底板相對時均壓強變幅較定曲率彎道最多減小達46.43%；數值模擬結果顯示凹凸兩岸水深的計算值與實測值能較好吻合，水流於彎道出口附近發生轉向。研究結果表明，變曲率彎道在超臨界流控制中明顯優於定曲率彎道。

關鍵字

變曲率彎道 ； 超臨界流 ； 水面超高 ； 數值模擬

並列摘要

Variable curvature bend is proposed in this paper for the problem of high superelevation and uneven pressure .Characteristics of fixed and variable bends were analyzed including flow pattern, water depth, water surface superelevation and pressure distribution, and a numerical simulation for variable curvature bend is conducted by fluent. The result indicates that: Compared with fixed curvature bend, the flow pattern is more stable, the maximum superelevation in whole bend significantly reduced a maximum of 15.1%, the possibility of bottom exposure at convex bank side and constrain of wall is much reduced, the variation amplitude of pressure in the bottom decreases a maximum of 46.43% in the variable curvature bend. The numerical result of variable curvature bend agrees well with experimental data for water depth, and flow direction changes in the vicinity of the bend outlet .The variable curvature bend is superior to the fixed curvature bend in the control of supercritical bend flow.

並列關鍵字

variable curvature bend ； supercritical flow ； water surface superelevation ； numerical simulation