旋流阻塞与旋流扩散复合内消能工强剪切两相流水力特性研究

Rotary flow internal energy dissipater is a feasible scheme of diversion tunnel reconstruction or new discharge tunnel construction in high dam, and has extensive adaptability. The wall pressure and velocity in vertex section will be influenced by the rotational blocking and diffuser complex internal energy dissipater, for this, the possibility of cavitation will be reduced, the energy dissipation will be increased, and the water head applicability will be more extensive. It is the rotary intense shear two-phase flow that the gas and water mixed fully behind the complex internal energy dissipater. In this applying project, the unique characteristics in this two-phase flow, such as flow pattern, gas escaping, wall pressure fluctuations, cavitation erosion, energy dissipation, and etc., will be systematically observed and studied by model test, numerical simulation and theoretical analysis. Based on this, the mixing mechanism of water and air, reduction of cavitation erosion on the tunnel wall, fluctuation characteristics of the flow, and mechanism and characteristics of energy dissipation will be studied further. These characteristics of the flow have the important relationship with the optimization of flow pattern, and the design of the type, anti-cavitation, wall lining, air vent, and etc. And it is a key to the popularization and application of the new energy dissipater. Therefore, this applying project has great significance and value to the basic application research in academic.

旋流内消能工是水利水电与各种防洪工程改建或新建泄洪洞的可行方案，具有广泛的适应性。采用新型的旋流阻塞与旋流扩散复合内消能工，可以控制旋流洞段的压强与速度，减免空蚀，提高作用水头和消能率。这种复合内消能工后为气水充分混掺形成的旋转强剪切两相流。本申请项目采用模型试验、数值模拟和理论分析相结合的方法，系统地观测旋转扩散条件下，这种两相流的流态、气体逸出、壁面压力脉动、空化空蚀和能量耗散等特有的两相流特性，深入研究气与水的混掺机理、旋转强剪切两相流的壁面减蚀、水流脉动特性和能量耗散机理与特性，填补这种旋转扩散两相流特性研究的空白。这些两相流特性也和泄洪洞兴建与改建过程中的流态优化、结构、抗空蚀、壁面衬砌和排气设计等有重要的关系，是使这种新型消能工能更为广泛的推广应用需要解决的关键性问题。因此本申请项目具有重要的科学意义与应用基础研究的价值。

本项目主要针对旋流阻塞与旋流扩散复合内消能工，采用模型试验、数值模拟和理论分析相结合的方法，对该消能工强剪切两相流的水力特性进行了研究。得到了该消能工两相流的流态、基本水力特性，以及气体逸出、壁面压力脉动、空化空蚀和能量耗散等特有的两相流特性，深入研究了气与水的混掺机理、旋转强剪切两相流的壁面减蚀、水流脉动特性和能量耗散机理与特性，填补了这种旋转扩散两相流特性研究的空白，并提出旋转扩散强剪切、高浓度壁面掺气率和高浓度断面含气率条件下的旋流扩散段的结构设计，壁面抗空蚀设计，消能率和排气设计的基本依据。这种旋流阻塞复合内消能工可适应并解决高山峡谷建坝时的高水头泄洪消能问题，本项目在该消能工两相流方面取得的研究成果，对该消能工的设计和应用具有重要的科学指导意义和推广应用价值。