【摘要】：水利工程中的泄水建筑物,包括溢流壩、溢洪道、泄洪洞等,當(dāng)下泄水流速度達(dá)到一定程度,即所謂的高速水流時(shí),由于水流速度高,壓強(qiáng)降低,當(dāng)水流壓強(qiáng)降低到一定程度后,水流中將產(chǎn)生空泡形成水流空化�？栈饔傻蛪簠^(qū)流到高壓區(qū),伴隨著空泡的生產(chǎn)、發(fā)展和潰滅,如果空泡的潰滅發(fā)生在流道固壁附近時(shí),其產(chǎn)生的微射流和輻射沖擊波作用在固壁上有可能造成空蝕破壞。 摻氣減蝕措施可以減免高速泄水建筑物的空蝕破壞。有壓洞出口采用突擴(kuò)突跌摻氣設(shè)施,會(huì)同時(shí)形成底空腔及側(cè)空腔,獲得較好的摻氣減蝕效果,對建筑物底板及側(cè)墻均起到良好的保護(hù)作用。在有壓洞出口變?yōu)槊鳁l件下,通過對突擴(kuò)突跌摻氣設(shè)施水工模型進(jìn)行不同突擴(kuò)寬度、跌坎高度、下游坡度、來流條件下的模型試驗(yàn),可以初步確定跌坎高度、突擴(kuò)寬度、下游坡度等參數(shù)對底、側(cè)空腔特性及水流摻氣的影響作用。 本文采用模型試驗(yàn)的方法對突擴(kuò)、突跌摻氣設(shè)施的水力特性進(jìn)行對比分析,通過試驗(yàn)研究,改變不同突擴(kuò)、突跌體型尺寸,形成不同突擴(kuò)比與突跌比的組合,以及改變不同的流量,來對比分析各方案、各工況下?lián)綒庠O(shè)施后的水流流態(tài)、壓力、水流空化數(shù)、摻氣濃度的沿程分布情況及摻氣空腔特性等水力要素的特征；利用多元函數(shù)擬合方法對試驗(yàn)測量數(shù)據(jù)進(jìn)行分析,得到與本次試驗(yàn)體型類似的計(jì)算側(cè)空腔與底空腔的經(jīng)驗(yàn)公式,可為水力條件和邊界條件相似的工程或進(jìn)一步的試驗(yàn)或理論研究提供參考。 本文采用數(shù)值模擬方法,利用Fluent等計(jì)算軟件、Eulerian雙流體模型計(jì)算方法,計(jì)算得出與模型試驗(yàn)相同邊界及水力條件下相應(yīng)方案、工況的水力特性參數(shù)。并將這些特性參數(shù)與模型試驗(yàn)實(shí)測所得的水力特性參數(shù)進(jìn)行對比,以檢驗(yàn)數(shù)值模擬方法的正確性及計(jì)算精度。 本論文揭示了突擴(kuò)突跌側(cè)摻氣和底摻氣兩種摻氣形式的機(jī)理的差異、相互影響和共同作用規(guī)律,研究成果對提高突擴(kuò)突跌摻氣設(shè)施全斷面摻氣減蝕效果,為該種摻氣減蝕設(shè)施的更好地應(yīng)用提供了有益的理論依據(jù)。
[Abstract]:In water conservancy projects, the drainage structures, including spillway, flood discharge tunnel, etc., when the downflow velocity reaches a certain level, that is, when the so-called high speed water flow, the pressure is reduced because of the high flow velocity. When the flow pressure is reduced to a certain extent, cavitation will occur in the flow. Cavitation flow flows from the low pressure region to the high pressure area, with the production, development and collapse of the cavitation bubble. If the cavitation collapse occurs near the wall of the channel, the micro jet and radiation shock wave may cause cavitation damage on the solid wall. Aeration erosion reduction measures can reduce cavitation erosion damage of high speed drainage structures. With the sudden expansion and falling aeration at the outlet of the pressure hole, both the bottom cavity and the side cavity will be formed, and the effect of aeration on corrosion reduction will be better, which will play a good protective role on both the floor and the side wall of the building. Under the condition that the outlet of the pressure tunnel becomes a celebrity, through the model tests on hydraulic models of sudden expansion, sudden fall in aeration facilities, different width of sudden expansion, height of fall ridge, downstream slope, and condition of incoming flow, the height of falling ridge and the width of sudden expansion can be preliminarily determined. The influence of the downstream slope and other parameters on the bottom, side cavity characteristics and flow aeration. In this paper, the hydraulic characteristics of sudden expansion and sudden fall aeration facilities are compared and analyzed by using the method of model test. Through the experimental study, the size of different sudden expansion and sudden fall type is changed, and the combination of different sudden expansion ratio and sudden drop ratio is formed. And changing different flow rate to compare and analyze the characteristics of hydraulic factors such as flow state, pressure, cavitation number of water flow, distribution of aeration concentration along the path and characteristics of aeration cavity, etc. By means of multivariate function fitting method, the experimental data are analyzed, and the empirical formulas for calculating the lateral cavity and the bottom cavity are obtained, which are similar to the shape of the experiment. It can be used as a reference for engineering with similar hydraulic and boundary conditions or for further experiments or theoretical studies. In this paper, the numerical simulation method is used to calculate the hydraulic characteristic parameters of the corresponding scheme under the same boundary and hydraulic conditions as the model test by using the calculation method of the Eulerian two-fluid model with Fluent et al. In order to verify the correctness and accuracy of the numerical simulation method, these characteristic parameters are compared with the hydraulic characteristic parameters measured in the model test. In this paper, the mechanism difference, mutual influence and common action law of two kinds of aeration forms of sudden expansion, falling side aeration and bottom aeration are revealed. The research results can improve the effect of whole section aeration to reduce corrosion of sudden expansion sudden fall aeration facilities. It provides a useful theoretical basis for the better application of the aerated corrosion abatement facility.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV135.2;TV131.3

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