台山核电厂引水隧洞进出水口阻力特性试验研究

结合台山核电厂输水系统工程，通过物理模型试验研究了引水隧洞不同粗糙度对进、出口段局部水头损失的影响规律。模型采用重力相似设计，比尺1∶18.9。在试验过程中，通过不断加大流量来改变模型水流雷诺数，依次得到不同糙率下的局部阻力系数随雷诺数变化曲线。局部阻力系数随雷诺数的增加而减小，其减小率随雷诺数的增加而下降，当雷诺数大于某临界值时，局部阻力系数逐渐趋于常数，说明水流进入阻力平方区，由此得到稳定后的局部阻力系数值。结果表明:不同粗糙度情况下，隧洞进、出口的局部阻力系数值变化明显，边壁粗糙度较大时，水流边界层受边壁绝对粗糙度影响，水流脉动跳跃离开边壁形成较大的涡流运动，水流能量耗散加强，对水流的阻力随之增大;局部阻力系数不仅与形状有关，还与隧洞的粗糙度有关，粗糙度越大，局部阻力系数越大，对于该项目，粗糙管比光滑管进口段局部阻力系数加大约45%，出口段局部阻力系数加大约56%。研究成果为实际工程输水系统设计提供了依据。

Experimental study on resistance characteristics at inlet and outlet of diversion tunnel for Taishan Nuclear Power Plant

Combined with the project of the circulating cooling water conveyance system for Taishan Nuclear Power Plant，the law of the influence from different roughness of its diversion tunnel on the local head losses at both the inlet and outlet sections is studied herein through the relevant physical modeling experiment，for which the design of dynamic similarity is adopted for the model with the scale of 1 ∶ 18. 9． During the experiment，the curves of the local resistance coefficients along with the changes of Ｒeynolds numbers under the conditions of different roughness are successively obtained through changing the Ｒeynolds number of the model flow by means of continuously increasing the flow rate． The local resistance coefficient is to be decreased along with the increase of the Ｒeynolds number，while its decreasing rate is to be decreased along with the increase of Ｒeynolds number． When Ｒeynolds number is larger than a certain critical value，the local resistance coefficient is to tend to a constant，which indicates that the flow comes into the square region of flow resistance，and then the stabilized local resistance coefficient is obtained． The result shows that the local resistance coefficients at both the inlet and outlet of the tunnel are significantly changed under the conditions of different coefficients． When the roughness on the side wall is larger，the water flow boundary layer is affected by the absolute roughness of the side wall，and then the flow pulsation jumps away from the side wall to form a large eddy motion，while the energy dissipation of the flow is enhanced along with the increase of the resistance to the water flow． The local resistance coefficient is not only related to the shape，but also related to the roughness of the tunnel，for which the larger the roughness is， the greater the local resistance coefficient is to be． For this project，the local resistance coefficient is to be increased by about 45% at the inlet section and by about 56% at the outlet section for rough pipe if compared with those of the smooth one． The study results can provide a basis for the design of the water conveyance system for the actual project concerned．