【摘要】：內消能工是高水頭泄水建筑物中有效的消能方式之一,齒墩式內消能工是一種新型的內消能工,這種消能工的提出是為了解決洞塞消能工過流能力低的不足。本文是山西省自然科學基金項目《齒墩式內消能工水力特性試驗研究》的部分內容,在前期對齒墩式消能工初步研究的基礎上,本文對齒墩式內消能工的水力特性做了進一步的研究,其體型為在有壓管道內均勻布置長度為0.9倍管道直徑的齒墩段,通過變化齒墩數(shù)量以及面積收縮比制定了10組不同的方案。采用物理模型試驗的方法,運用多普勒超聲波流速儀、高精度數(shù)字壓力傳感器對不同方案不同流量組別情況下的壓強、流速進行了測量。分析得到各方案壓強分布的變化規(guī)律、流量系數(shù)、水頭損失系數(shù)、消能率以及水平流速分布的變化規(guī)律。分析了齒墩數(shù)量以及面積收縮比對消能特性的影響,齒墩消能工的消能機理、水平流速分布特性以及齒墩式內消能工的脈動壓強特性。主要結論有： 1、在保證一定過流能力的情況下,齒墩式消能工的消能率能達到較高的程度。在流量系數(shù)為0.407的情況下,消能率可以達到80%以上,是一種具有發(fā)展?jié)摿Φ膬认芄ぁ?2、在試驗流量情況下,各方案壁面時均壓強系數(shù)沿程的變化規(guī)律相似,均為在齒墩進口段急劇下降,在齒墩段內達到最低,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)量的變化對其影響較小。 3、通過對壓強數(shù)據(jù)的分析,得到脈動壓強沿程分布的變化規(guī)律。脈動壓強的變化幅度均是在齒墩段處變化最大,且面積收縮比越大脈動壓強在齒墩段的變化幅度越小,脈動壓強最大點出現(xiàn)在齒墩段后1.0D-1.6D的范圍內。壓強脈動幅值隨著面積收縮比的減小而增大。 4、通過對試驗方案最大脈動壓強的概率密度分布、偏態(tài)系數(shù)和峰態(tài)系數(shù)的分析,得到各方案的分布來基本接近于正態(tài)分布。 5、通過對齒墩式內消能工流量系數(shù)隨雷諾數(shù)變化情況的分析,得知過流能力與雷諾數(shù)無關。面積收縮比是影響過流能力的主要因素,面積收縮比越小管道過流能力越差。 6、齒墩式內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,各方案突擴水頭損失系數(shù)的變化規(guī)律與理論值比較吻合。 7、通過對齒墩段前后管道內水流水平流速的數(shù)據(jù)分析,得到典型斷面水平流速分布圖、水平流速矢量圖以及典型深度脈動流速沿程的變化規(guī)律。
[Abstract]:The inner energy dissipator is one of the effective energy dissipation methods in the high head drain structure. The toothed pier type inner energy dissipator is a new type of inner energy dissipator, which is put forward to solve the deficiency of the low overcurrent capacity of the cavity-plug energy dissipator. This paper is part of the project of Shanxi Natural Science Foundation, "Experimental study on hydraulic characteristics of inner energy dissipators with tooth piers", on the basis of preliminary research on tooth pier type energy dissipators. In this paper, the hydraulic characteristics of the inner energy dissipators with tooth piers are further studied. The shape of the piers is that the tooth piers with a length of 0.9 times the diameter of the pipe are uniformly arranged in the pressurized pipeline. By changing the number of tooth piers and the area shrinkage ratio, 10 groups of different schemes were developed. The physical model test method is used to measure the pressure and velocity of different schemes and different flow groups by using Doppler ultrasonic velocimeter and high precision digital pressure sensor. The variation law of pressure distribution, flow coefficient, head loss coefficient, energy dissipation rate and horizontal velocity distribution are obtained. The effects of the number of tooth piers and the area shrinkage ratio on the energy dissipation characteristics, the energy dissipation mechanism of the tooth pier dissipators, the horizontal velocity distribution and the pulsating pressure characteristics of the internal energy dissipators of the tooth piers are analyzed. The main conclusions are as follows: 1. Under the condition of certain overcurrent capacity, the energy dissipation rate of the tooth pier type energy dissipator can reach a higher degree. When the flow coefficient is 0.407, the energy dissipation rate can reach more than 80%, and it is a kind of internal energy dissipator with potential development. 2. Under the experimental flow rate, the variation law of the average pressure coefficient along the wall of each scheme is similar. The pressure recovery length is mainly affected by the area shrinkage ratio, which decreases sharply in the inlet section of the tooth pier, reaches the lowest in the tooth pier section, and then recovers gradually, and the pressure recovery length is mainly affected by the area shrinkage ratio. The change of the number of tooth piers has little effect on it. 3. Through the analysis of pressure data, the variation law of pulsating pressure along the course is obtained. The variation range of pulsating pressure is the largest at the tooth pier, and the larger the area shrinkage ratio is, the smaller the fluctuating pressure is in the tooth pier segment, and the maximum pulsating pressure point appears in the range of 1.0D-1.6D behind the tooth pier segment. The amplitude of pressure pulsation increases with the decrease of area contraction ratio. 4. The probability density distribution, skewness coefficient and peak coefficient of the maximum pulsating pressure of the test scheme are analyzed. The distribution of each scheme is close to normal distribution. 5. By analyzing the change of flow coefficient with Reynolds number, it is found that the overcurrent capacity has nothing to do with Reynolds number. The area shrinkage ratio is the main factor affecting the overcurrent capacity, and the smaller the area shrinkage ratio, the worse the flow capacity. 6, the head loss coefficient of the inner energy dissipator increases with the decrease of the area shrinkage ratio. In the case of the same area shrinkage ratio, the head loss coefficient of different tooth piers has little difference. The variation law of loss coefficient of sudden expansion head of each scheme is in good agreement with the theoretical value. 7. By analyzing the data of horizontal flow velocity in the pipeline before and after the tooth pier section, the horizontal velocity distribution map of typical section is obtained. The variation of horizontal velocity vector diagram and typical depth pulsation along the flow path.
【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;TV135.2

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