水利学报
水利學報
수리학보
2014年
10期
1247-1255
,共9页
孙昕%叶丽丽%刘伟%解岳%卞晶
孫昕%葉麗麗%劉偉%解嶽%卞晶
손흔%협려려%류위%해악%변정
曝气%内波%消减分层%温度梯度%水库
曝氣%內波%消減分層%溫度梯度%水庫
폭기%내파%소감분층%온도제도%수고
aeration%internal waves%destratification%temperature gradient%reservoir
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%。
水溫分層是深水型水庫水質內源汙染的主要誘因。針對現有消減水溫分層技術的高能耗問題,嘗試利用颺水曝氣器的週期性齣流作為擾動源,在氣水兩相流條件下誘導產生內波。基于模型水庫水溫垂嚮密度剖麵的歷時信息,計算水庫內波的特徵參數,分析內波的特性及其消減水溫分層的效果。噹曝氣量為50~200 L/h、躍溫層溫度梯度為0.34~0.49℃/cm時,在特定條件下能產生內波,內波的波幅在躍溫層浮力頻率最小處最大。隨曝氣時間推移,內波的能量逐漸耗散,波幅逐漸減小,內波有破碎趨勢。隨曝氣量減小,內波的特徵參數值的總趨勢是先逐漸增大到極值,再逐漸減小。隨溫度梯度增大,內波週期有減小趨勢,波速、波長、波幅則相反。內波特性受溫度梯度影響較大。在本中試條件下,相對傳統的循環水流混閤,內波混閤可使消減分層的效率提高25%~60%。
수온분층시심수형수고수질내원오염적주요유인。침대현유소감수온분층기술적고능모문제,상시이용양수폭기기적주기성출류작위우동원,재기수량상류조건하유도산생내파。기우모형수고수온수향밀도부면적력시신식,계산수고내파적특정삼수,분석내파적특성급기소감수온분층적효과。당폭기량위50~200 L/h、약온층온도제도위0.34~0.49℃/cm시,재특정조건하능산생내파,내파적파폭재약온층부력빈솔최소처최대。수폭기시간추이,내파적능량축점모산,파폭축점감소,내파유파쇄추세。수폭기량감소,내파적특정삼수치적총추세시선축점증대도겁치,재축점감소。수온도제도증대,내파주기유감소추세,파속、파장、파폭칙상반。내파특성수온도제도영향교대。재본중시조건하,상대전통적순배수류혼합,내파혼합가사소감분층적효솔제고25%~60%。
Thermal stratification is the main inducement of internal water quality pollution in deep reser?voirs. Aiming at the common problem of high energy consumption of conventional destratification technolo?gies, periodic outflow from a water-lifting aerator was first used as a disturbing source to induce the inter?nal 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 investigat?ed. 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 ener?gy, and the breaking of internal waves seemed to happen at the end of wave propagation. The characteris?tics 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 condi?tions.