【摘要】：大伙房水庫位于中國東北部,是遼寧省重要的的水源地之一,保護水庫的水質對于遼寧省的經濟發(fā)展和社會穩(wěn)定具有重要的戰(zhàn)略意義。大伙房水庫屬于山區(qū)河谷型水庫,注入上游的營養(yǎng)物質有可能需要很長的時間才能到達下游區(qū)域,這使得營養(yǎng)物質的輸運時間對于水體的水質狀況有著重要影響。因此深入研究大伙房水庫的水動力特征,綜合分析不同因素對于大伙房水庫輸運時間的影響顯得尤為重要。本文采用數值模擬的方法對大伙房水庫的水動力特征以及輸運時間的影響因素進行了研究。 本文首先利用基于結構化網格的環(huán)境水動力模型EFDC (Environmental Fluid Dynamics Code),綜合考慮風、表層熱通量以及入庫徑流,建立了大伙房水庫三維水動力模型。通過對比水位和溫度的模擬值與實測值對模型進行了驗證,驗證結果表明建立的水動力模型能夠很好地再現水庫水位的升降規(guī)律和溫度的分層一-混合變化過程。 然后利用建立的水動力模型,對大伙房水庫水體的水齡進行數值模擬研究,綜合分析了徑流、風、表層熱通量及水位變化對于水齡的影響。結果表明徑流是影響水齡的主要因素,僅有徑流驅動時,在高、平均、低流量下,溢洪道處水體的水齡分別為53.93天、126.96天、458.78天,河道橫斷面上中間水齡小、兩側水齡大。風對水體輸運時間的影響主要通過風生流和風生混合的作用體現出來。同時考慮徑流和風的作用時,水齡沿河道橫斷面的差異減小,在垂向上水齡則是完全均一的。與僅考慮徑流時的水齡相比,深水河道處的水齡增加值高于其它河道處水齡的增加值,流量較大時,風對下游水體的水齡影響較大,而流量較小時,風對上游水體的水齡影響較大。表層熱通量對輸運時間的影響主要通過密度流和溫躍層體現出來,當考慮表層熱通量的作用時,水齡在局部區(qū)域沿水平方向的差異減小,在垂向上呈現表層水齡小、底層水齡大的分層特征,并且越往下游表底層差異越大。表層熱通量對表層水體的水齡影響較小,對底層水體的水齡影響較大。水位變化通過改變水體的溫度結構從而影響著水體的水齡,水位降低時,水齡整體減小,而且水齡垂向上的差異減小,水位變化對底層和下游水體水齡的影響強于對表層和上游水體水齡的影響。 通過已經建立的水動力模型,研究了流量變化對于滯留時間的影響。計算結果表明：在庫區(qū)河道上,距離大壩越遠,滯留時間越大,當地滯留時間越小,而且當地滯留時間和對應區(qū)域的滯留時間的差別越大。滯留時間和當地滯留時間隨時間的變化服從指數分布,當流量低于平均流量時,滯留時間和當地滯留時間隨流量減小而急劇增大。
[Abstract]:Dahuofang Reservoir is located in the northeast of China and is one of the important water sources in Liaoning Province. Protecting the water quality of the reservoir is of great strategic significance to the economic development and social stability of Liaoning Province. Dahuofang Reservoir belongs to the valley type reservoir in mountainous area. It may take a long time for the nutrient injected upstream to reach the downstream area, which makes the transport time of nutrients have an important impact on the water quality. Therefore, it is very important to study the hydrodynamic characteristics of Dahuofang Reservoir and analyze the influence of different factors on the transportation time of Dahuofang Reservoir. In this paper, the hydrodynamic characteristics of Dahuofang Reservoir and the influence factors of transportation time are studied by numerical simulation method. In this paper, a three-dimensional hydrodynamic model of Dahuofang Reservoir is established based on structured grid based environmental hydrodynamic model (EFDC (Environmental Fluid Dynamics Code), considering wind, surface heat flux and inflow runoff. The model is verified by comparing the simulated and measured values of water level and temperature. The results show that the hydrodynamic model can well reproduce the fluctuation law of reservoir water level and the process of stratified and mixed variation of temperature. Then the hydrodynamic model is used to simulate the water age of Dahuofang Reservoir and the effects of runoff wind surface heat flux and water level on water age are analyzed. The results show that runoff is the main factor affecting water age. When runoff is only driven by runoff, the water age at spillway is 53.93 days, 126.96 days and 458.78 days, respectively, under the condition of high, average and low discharge, the middle age of river channel is small, and the water age of both sides is large. The influence of wind on water transport time is mainly reflected by wind-induced flow and wind-induced mixing. At the same time considering the effect of runoff and wind the difference of the cross section along the river channel decreases and the water age is uniform in vertical direction. Compared with the water age when only considering the runoff, the increase value of the water age in the deep water channel is higher than that in the other rivers. When the discharge is larger, the wind has a greater influence on the water age of the downstream water body, but the flow rate is smaller. Wind has a great influence on the water age of upstream water body. The effect of surface heat flux on transport time is mainly reflected by density flow and thermocline. When the effect of surface heat flux is considered, the difference of water age along horizontal direction decreases in local area, and the surface water age is small in vertical direction. The delamination characteristics of the lower water age, and the greater the difference between the bottom layer and the downstream surface. The influence of surface heat flux on water age of surface water is small, and that on water age of bottom water is greater. The variation of water level affects the water age by changing the temperature structure of the water body. When the water level decreases, the water age decreases as a whole, and the vertical difference of water age decreases. The influence of water level change on water age of bottom and downstream water is stronger than that on surface and upstream water age. Based on the established hydrodynamic model, the effect of flow rate change on residence time is studied. The calculation results show that the farther away from the dam, the larger the detention time, the smaller the local detention time, and the greater the difference between the local detention time and the corresponding region. When the flow rate is lower than the average flow rate, the residence time and the local residence time increase sharply with the decrease of the flow rate.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV697

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本文編號：2214559