溢洪道的消能模擬研究

本文透過單階跌水驗證、坡地排水渠道消能驗證及階梯溢洪道紊流模型驗證來確認本文模型設定的可靠性，針對流量0.0075cms與0.01cms的階梯高度0.03m、0.045m及0.06m階梯溢洪道與3-2排列、3排列與2排列的墩塊溢洪道進行數值模擬研究。研究結果顯示墩塊溢洪道的消能會受到有無墩塊排列斷面與水流跳躍距離的影響，其中3-2排列溢洪道在三種墩塊溢洪道排列中總墩塊消能率最高。階梯溢洪道的消能則受到水流型式與渦流大小的影響，其中以階梯高度0.06m的階梯溢洪道總消能率最高。階梯的總消能率又比墩塊總消能率良好，兩組流量總階梯溢洪道消能率與總墩塊溢洪道消能率平均相差12.8%。針對階梯與墩塊溢洪道的總階梯消能率來看，在流量0.0075cms時大於流量0.01cms平均相差4.9%。也對不同流量的淨消能工消能率來討論，階梯或墩塊淨消能率皆比流量0.0075cms多平均5.6%，此時階梯或墩塊所站的消能比重較重，是由於光滑消能部分消能效果下降，但階梯或墩塊的消能率變化小(平均1.8%)；在相同階梯溢洪道高度下，階梯數越多階梯溢洪道總消能率與淨消能率越低。

關鍵字

數值模擬；消能；溢洪道；階梯；墩塊

並列摘要

This study affirms the reliability of the model set through the verifications of free falling of unit-step, slope drainage channel energy dissipation, and stepped spillway turbulence model. The flow rate of 0.0075cms and 0.01cms, the step height of 0.03m, 0.045m, and 0.06m is carried out with 3-2, 3, and 2 arrangements pier block spillway. The results of this study show that the energy dissipation of the pier block spillway will be affected by the presence or absence of the pier block arrangement section and the water jump distance. Among the three pier block spillway arrangements, the 3-2 arrangement of the spillway has the highest total pier block energy dissipation rate. The energy dissipation of the stepped spillway is affected by the flow pattern and the size of the vortex, and the stepped spillway with a step height of 0.06m has the highest total energy dissipation rate. The total energy dissipation rate of the step is better than the total energy dissipation rate of the pier. The difference between the total energy dissipation rate of the two sets of steps and the total pier spillway is 12.8% on average. In terms of the total spillway energy dissipation rate of steps and piers, the average difference of 4.9% was obtained by the flow rate of 0.0075cms, that is higher than 0.01cms. Moreover, the net energy dissipation rate of steps or piers obtained by the flowrate of 0.01cms is 5.6% that is higher than 0.0075cms. The net energy dissipation effect of the energy dissipation part decreases, but the energy dissipation rate of steps or piers has a small change (average 1.8%); under the same stepped spillway height, the more of the steps number, the lower of the total energy dissipation rate and net energy dissipation rate of the stepped spillway.

並列關鍵字

Numerical simulation ； Energy dissipation ； Spillway ； Steps ； Pier block

參考文獻

Google Scholar

Chen, Q., Dai ,Guangqing. and Liu, H. (2002), “Volume of Fluid Model for Turbulence Numerical Simulation of Stepped Spillway Overﬂow,” Journal of Hydraulic Engineering, vol. 128, pp.683-688.