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目的:输水管道的驼峰气阻是指由于管路高峰位置的滞气作用使气体不断聚积在峰顶附近、产生的气体阻碍水流的局部水力现象。它能够导致管路过水断面减小、输水能耗增加、输送效率降低和管路压力振荡等后果,严重威胁海底管道输水的稳定性和安全性。本文旨在分析滞留气团在供水管道中的力学平衡、能量损失、移动和溢出机理,研究水流流速对气团的推移特性,提出预测和消除驼峰气阻的方法,使输水管道免受驼峰气阻的危害,提高输水管道的供水效率。创新点:1.设计了具有连续坡角变化的圆弧形驼峰管道实验,该实验可以定量模拟气团体积和平衡角度;2.建立了驼峰气阻的水头损失经验公式和恒定流情况下驼峰气阻的管道坡角和流速的对应关系式,可用于预测和消除驼峰气阻的危害。方法:1.通过驼峰气团的受力特性分析,获得满足量纲和谐的力学平衡方程;2.采用试验观察和测试获得有无气泡情况下的水头损失和平衡状态下的坡角,通过等价球体方法对测试数据进行无量纲拟合,获得气阻的水头损失方程系数,并通过流速和平衡坡角建立恒定流情况下的临界平衡方程;3.基于试验拟合获得临界平衡方程,建立预测和评估气阻的准则系数,并提出消除气阻的水流临界流速。结论:1.当管路流速较小时,供水管路的驼峰顶端可能滞留和聚集气体,形成驼峰气阻;气体体积越大对水流阻碍越明显,可能造成的水头损失也越大;2.利用等价球体法可以极大地简化驼峰气阻的形状,并良好地模拟气阻的平衡特性和阻力特性;3.管道流速是影响驼峰气阻临界平衡位置的最重要因素,通过减小管道起伏的坡角或增加水流流速可以防止和消除驼峰气阻的危害。
PURPOSE: The hump air resistance of a water conveyance pipe is the local hydraulic phenomenon that the gas produced impedes the flow of water due to the continuous accumulation of gas at the peak due to the hysteresis at the peak of the pipe. It can lead to pipeline cross-section reduction, increased water consumption, transport efficiency and pipeline pressure oscillations and other consequences, a serious threat to submarine pipeline water stability and safety. The purpose of this paper is to analyze the mechanics balance, energy loss, movement and spillover mechanism of trapped air mass in water supply pipeline, to study the characteristics of water flow velocity on air mass movement, to propose a method to predict and eliminate hump gas resistance, Of the hazards and improve the efficiency of water supply pipelines. Innovative points: 1. Designed a circular hump pipe experiment with continuous change of slope angle, the experiment can quantitatively simulate the volume of the air mass and the balance angle; 2. The empirical formula of the head loss of the hump gas resistance and the hump gas Resistance of the pipeline angle and flow rate of the corresponding relationship between the formula can be used to predict and eliminate the hump gas resistance hazards. The mechanical balance equation which satisfies the dimension harmony is obtained through the analysis of the force characteristics of the hump air mass.2. The head loss and the angle of slope in the presence or absence of bubbles are obtained by experimental observations and tests. Sphere method to test the data without dimension fitting, get the head loss equation of air resistance coefficient, and through the flow rate and the balance of slope angle to establish a constant flow case of the critical balance equation; 3. Based on the experimental fitting to obtain the critical equilibrium equation, the establishment of prediction And the criterion coefficient of gas resistance is evaluated, and the critical flow velocity of gas flow to eliminate gas resistance is proposed. Conclusions: 1.When the pipeline flow rate is small, the top of the hump of the water supply pipeline may stagnate and gather gas to form the hump gas resistance; the larger the gas volume is, the more obvious the water flow obstruction will be, and the greater the head loss may be caused; 2. Equivalent sphere method can greatly simplify the shape of hump gas resistance, and well simulate the balance characteristics and resistance characteristics of air resistance; 3. Pipe flow rate is the most important factor affecting the critical equilibrium position of hump gas resistance, by reducing the undulating Slope angle or increase the water flow rate can prevent and eliminate the hump gas resistance hazards.