【作者】 李娜；

【导师】 马希金；

【作者基本信息】 兰州理工大学 ， 流体机械及工程， 2016， 硕士

【摘要】 在能源越来越急需的时代,为了使油田寿命得以延长并提高采油率,多相混输技术越来越显示其重要性和必要性。油气混输泵属于轴流式叶片机械,是一种低效率的水力机械,是因为随着含气率的增大气液两相会发生分离,形成气堵现象,阻碍流体流动。如果能将相态分离所产生的滞留气团通过排放或粉碎等方式排出泵体,则泵的性能将会得以改善,因此可以在结构上采取一些措施,改善泵在输送多相介质时的性能。本文就从这一点出发,以自主研发的YQH-100油气混输泵作为研究对象,采用理论分析与数值模拟相结合的方法进行研究分析,研究内容和结果如下:1.在动叶叶片上添加不同尺寸的附属结构“辅翼”,进行计算分析。首先在动叶片上添加尺寸为从叶片头部延伸到尾部的全“辅翼”,有三种方案:方案一(PW)在叶片背面添加辅翼(Pressure side Wing);方案二(SW)在叶片工作面添加“辅翼”(Suction side Wing);方案三(DW)在叶片两面均加“辅翼”(Double side Wing)。在五种含气率(0,10%,30%,50%,80%)下,通过模拟计算,分析三种方案下油气混输泵的性能,然后选取方案较优的一种结构,改变“辅翼”的尺寸,改为从叶片中间延伸到叶片尾部的半“辅翼”(Half-suction side Wing)即方案HSW,同样进行五种工况下的数值模拟,又进行了纯水状态下变流量的计算。2.方案一PW、方案二SW、方案三DW中,由于在动叶叶片上增加了附属结构,水力损失增大,使得油气混输泵的扬程和效率均降低,在叶片背面添加辅翼的方案降低值相对较小,从气液混合现象来看,添加辅翼可以有效的促进气液混合,气液混合更均匀。方案HSW,在纯水工况下,扬程和效率均高于原模型;含气率变化时,扬程和效率均有所提高,压力分布更均匀,相比原模型,气液混合效果更佳,而且在高含气率下效果更明显,同时叶轮的增压能力增。从外特性和内流场结构两方面来看,HSW方案达到预期效果,且最为可行。3.在动叶片上气体聚集处开若干小孔,通过叶片工作面和叶片背面所形成的压差来形成流体的贯穿,打碎气囊。打孔的位置在叶片中间靠近叶片出口的某段位置上,且靠近轮毂处,因为该处是气泡最容易积聚的区域。开孔个数分别为2个和4个,记为“2K、4K”,孔的直径大小取为3mm,分别在含气率为0,10%,30%,50%,80%五种工况下进行数值模拟,并且跟叶片上不开孔的原模型“OM”的情况下比较分析。在高含气率工况下,方案2K和方案4K均使油气混输泵的扬程和效率都比不开孔的情况下有所提高;在叶轮轮毂处靠近叶片出口形成的气团现象有所改善,气体聚集区域减小,气液分布均匀,使得气液混合能力提高,而且叶片开孔后,叶轮的增压能力也比原型的增压能力强。更多还原

【Abstract】 In an age of increasing demand in energy, in order to make the existing oil fields to prolong life and improve oil recovery rate, multiphase mixing technology shows its importance and necessity more and more. We all know that oil-gas mixed pump is a axial flow vane machinery and is also a kind of low efficiency hydraulic machinery,because two phases would separate with the increasing of gas void fraction(GVF),emerging the air mass, hindering the fluid flow. If we can trapped gas emissions or smashed from the pump, the performance of pump will be improved. Therefore we can adopt some measures in structure to improve the pump. This article starts from the point, the self-developed YQH-100-type oil-gas mixed pump was studied as a object,the major research content and results are as follows:1.Adding different size “auxiliary wing” on the rotor vane to calculate. First, 3schemes of the “auxiliary wing ” size stretched from the head of blade to the end of blade:The scheme one adds “auxiliary wing” to the pressure side of the rotor vane; the scheme two adds“auxiliary wing” to the suction side of the rotor vane;the scheme three adds “auxiliary wing” to the double side of the rotor vane. The numerical simulation was carried out under the condition that the GVF are 0, 10%, 30% 50%,80%, respectively. Analysis the performance of the oil-gas mixture pumps under the three schemes, and then choose the better structure of the schemes, changing the“auxiliary wing” size stretched from the middle of blade to the end of blade.Similarly,the numerical simulation was carried out under the five conditions, and the calculation of variable flow water condition was carried out too.2.In the three schemes, due to increased the subsidiary structure, hydraulic loss was increased, making the head and efficiency of the oil-gas mixed pump decreased.Relatively, adding “auxiliary wing” to the suction side of the rotor vane reduced small.From the point of gas-liquid mixing phenomenon, adding “auxiliary wing” could effectively promote the gas-liquid mixing, and even more. Under the working condition of pure water, the scheme of adding Half-suction side Wing was better than the previous schemes, head and efficiency were higher than the original model; with the GVF changed, the head and efficiency was raised, the pressure distribution more uniform, gas-liquid mixing effects was also better than that of original model,the effect was more obvious under the high GVF, also the capability of impeller of pressurization was enhanced. Both in terms of the outer and inner characteristic offlow field structure, the method of HSW was the best and most feasible.3.Opening holes on the blades where gas packets appear, through the different pressure caused by the fluid from the pressure side and suction side of blade to break gas packets, inhibiting gas-liquid separation.The location of holes was in the middle of the blade near the outlet position and near the hub, because it was the easiest gathering area of bubbles. The number of hole defined two and four, respectively, the diameter was 3 millimeters. The numerical simulation was carried out under the five condition that the GVF are 0, 10%, 30%, 50%, 80%, and comparing with the original model. The study shown that the schemes of 2K and 4K were all enhanced the head and efficiency of the oil-gas mixed pump under the high GVF, the gas packets gathered in the impeller near the outlet blade were improved, the distribution of gas-liquid was improved too. The amended impeller with opening the hole exhibits the head rise, which was even better than that of the original impeller.更多还原