本文選題：齒墩狀內(nèi)消能工 + 水力特性　； 參考：《太原理工大學》2014年碩士論文

【摘要】：內(nèi)消能工具有布置簡單、經(jīng)濟實用、消能效率高等優(yōu)點,并且在水利工程中具有廣闊的應(yīng)用前景及良好的經(jīng)濟效益,對其研究意義重大。本文在前人對齒墩狀內(nèi)消能工初步研究的基礎(chǔ)上,采用物理模型試驗方法對齒墩狀內(nèi)消能工的水力特性進行了進一步的研究,分析不同布置方案的齒墩狀內(nèi)消能工的過流能力、水頭損失、時均和脈動壓強分布規(guī)律、管道流速分布等。主要討論齒墩消能工的齒墩數(shù)量和面積收縮比對上述特性的影響,通過分析得到的主要結(jié)論有： 1.管道過流能力由消能工體型決定,與Re關(guān)系不大。面積收縮比是影響過流能力的主要因素,面積收縮比越小,過流面積越小,管道過流能力越差,面積收縮比由0.375增加至0.625時,流量系數(shù)由0.35變化為0.8。 2.隨著管道中流量的增加,齒墩狀消能工的消能率也相應(yīng)增加。流量相同時,收縮比越小,消能率越高。試驗范圍內(nèi),消能率最大可達到80%左右。 3.齒墩式內(nèi)消能工在消能段的水頭損失系數(shù)隨著面積收縮比的減小而增大,相同面積收縮比情況下,不同齒墩數(shù)的水頭損失系數(shù)差別不大。 4.各方案壁面時均壓強系數(shù)沿程總體變化規(guī)律相似,都是在齒墩進口段急劇下降,在齒墩段內(nèi)達到最低,之后逐漸恢復,壓強恢復長度主要受面積收縮比的影響,齒墩數(shù)量的變化對其也有一定影響。 5.各試驗方案中,面積收縮比越小,齒墩段前后存在的回流區(qū)范圍越大,面積收縮比相同時,齒墩數(shù)目越多,其回流區(qū)涉及范圍越大。 6.各方案脈動壓強最大值均出現(xiàn)在齒墩段后1.3D～1.6D范圍內(nèi),面積收縮比越小,其脈動壓強越大,在試驗范圍內(nèi),脈動幅值變化可達到2倍速度水頭。 7.各試驗方案的消能工脈動壓強系數(shù)隨著面積收縮比的減小而增大,面積收縮比相同的情況下,齒墩數(shù)目的增加對脈動壓強系數(shù)有一定的影響 8.各方案的脈動壓強的概率密度分布偏態(tài)系數(shù)在-0.38-0.3范圍內(nèi),峰態(tài)系數(shù)在2.92-4.06之間變化,其分布基本接近于正態(tài)分布。
[Abstract]:The inner energy dissipation tools have the advantages of simple layout, economic utility, high energy dissipation efficiency, and have broad application prospects and good economic benefits in water conservancy projects, which is of great significance to its research. In this paper, based on the preliminary study on the internal energy dissipators of the tooth piers, the hydraulic characteristics of the inner dissipators of the tooth piers are further studied by using the physical model test method, and the overcurrent capacity of the inner dissipators with different arrangement schemes is analyzed. Head loss, time average and pulsating pressure distribution, pipeline velocity distribution, etc. This paper mainly discusses the influence of the number of tooth piers and the area shrinkage ratio of tooth dissipators on the above characteristics. The main conclusions are as follows: 1. The pipeline overcurrent capacity is determined by the energy dissipator's shape and has little relation to re. The area shrinkage ratio is the main factor affecting the overcurrent capacity. The smaller the area shrinkage ratio is, the smaller the overcurrent area is, the worse the over-current capacity of the pipeline is. When the area shrinkage ratio increases from 0.375 to 0.625, the flow coefficient changes from 0.35 to 0.8. 2. With the increase of flow rate in pipeline, the energy dissipation rate of toothed pier energy dissipator increases accordingly. At the same flow rate, the smaller the shrinkage ratio, the higher the energy dissipation rate. In the range of test, the maximum energy dissipation rate can reach about 80%. 3. The head loss coefficient of the inner energy dissipator increases with the decrease of the area shrinkage ratio, but the water head loss coefficient of different tooth piers is not different with the same area shrinkage ratio. 4. The variation law of the average pressure coefficient along the course of the wall surface is similar, all of them decrease sharply in the inlet section of the tooth pier, reach the lowest level in the tooth pier section, then recover gradually, and the pressure recovery length is mainly affected by the area shrinkage ratio. The change of the number of tooth piers also has a certain effect on it. 5. In each test scheme, the smaller the area shrinkage ratio is, the larger the range of reflux zone is before and after the tooth pier section. When the area shrinkage ratio is the same, the more the number of tooth piers is, the larger the range of return zone is. 6. The maximum pulsation pressure of each scheme appears in the 1.3D~1.6D range behind the tooth pier. The smaller the area shrinkage ratio, the greater the pulsating pressure. In the range of test, the fluctuation amplitude can reach 2 times the velocity of water head. 7. The pulsating pressure coefficient of energy dissipators increases with the decrease of the area shrinkage ratio. The increase of the number of tooth piers has a certain effect on the pulsating pressure coefficient when the area shrinkage ratio is the same. 8. The bias coefficient of the probability density distribution of the pulsating pressure of each scheme is in the range of -0.38-0.3, and the peak coefficient varies from 2.92-4.06, and its distribution is basically close to the normal distribution.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV653;TV131.61

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