| 孙昕,叶丽丽,刘伟,解岳,卞晶.分层水库曝气诱导内波特性及消减分层效果[J].水利学报,2014,45(10): |
| 分层水库曝气诱导内波特性及消减分层效果 |
| Characteristics and effectiveness of destratification of aeration-induced internal waves in a stratified reservoir |
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| DOI： |
| 中文关键词: 曝气 内波 消减分层 温度梯度 水库 |
| 英文关键词: aeration internal waves destratification temperature gradient reservoir |
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| 中文摘要: |
| 水温分层是深水型水库水质内源污染的主要诱因。针对现有消减水温分层技术的高能耗问题，尝试利用扬水曝气器的周期性出流作为扰动源，在气水两相流条件下诱导产生内波。基于模型水库水温垂向密度剖面的历时信息，计算水库内波的特征参数，分析内波的特性及其消减水温分层的效果。当曝气量为50～200 L/h、跃温层温度梯度为0.34～0.49 ℃/cm 时，在特定条件下能产生内波，内波的波幅在跃温层浮力频率最小处最大。随曝气时间推移，内波的能量逐渐耗散，波幅逐渐减小，内波有破碎趋势。随曝气量减小，内波的特征参数值的总趋势是先逐渐增大到极值，再逐渐减小。随温度梯度增大，内波周期有减小趋势，波速、波长、波幅则相反。内波特性受温度梯度影响较大。在本中试条件下， 相对传统的循环水流混合， 内波混合可使消减分层的效率提高25 %～60 %。 |
| 英文摘要: |
| Thermal stratification is the main inducement of internal water quality pollution in deep reservoirs. Aiming at the common problem of high energy consumption of conventional destratification technologies， periodic outflow from a water-lifting aerator was first used as a disturbing source to induce the internal waves under air-water two-phase conditions， characteristic parameters of internal waves were calculated according to the variations of vertical profiles of temperature-dependent density in the model reservoir， and the characteristics of internal waves and the effectiveness of destratification by internal waves were investigated. Under air flowrates of 50～200 L/h and temperature gradients of 0.34～0.49 ℃/m in the thermocline，the internal waves could be generated， the wave amplitude peaked where the buoyancy frequency was the lowest in the thermocline. The wave amplitudes decreased gradually with time due to the dissipation of energy， and the breaking of internal waves seemed to happen at the end of wave propagation. The characteristics of internal waves showed general trends that they increased to maximum values and then decreased gradually as the air flowrates increased. The wave periods decreased as the temperature gradients increased，but the wave velocities， wave lengths and wave amplitudes were the opposite. Characteristics of internal waves were more sensitive to the temperature gradient. Compared with the conventional mixing by circulated flow， the mixing by internal waves could be enhanced by 25 %～60 % under the pilot experimental conditions. |
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