旋流式射流泵装置性能研究

发布时间：2018-03-10 03:15

本文选题：旋流式射流泵　切入点：性能　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：我国作为一个水资源区域分布不均匀且严重缺水的国家,河床水位与地下水水位逐年下降,导致很多地区水位距离地面的高度差达到8m以上。射流泵装置作为一种高吸程抽水装置,其吸程可达数十米,具有工作可靠、维修便捷、成本低廉以及在缺电环境下能通过其它动力运行等优点,但由于自身工作原理的特点,其装置性能较差,运行效率偏低。因此,本文对射流泵结构提出改进,设计了一种固定导叶型旋流式射流泵,并对其装置性能进行研究,以达到提升射流泵装置性能的目的,主要研究内容有:(1)理论分析旋动射流的速度和压力衰减特性以及其卷吸能力和掺混作用,并将旋动射流理论应用于射流泵中,设计一种固定导叶型旋流式射流泵。结果表明,工作水为弱旋动射流的射流泵内,其径向和轴向的速度以及压力比工作水为强旋动射流时扩散衰减得更慢,其卷吸能力和掺混作用则比无旋动射流强很多,有助于提升射流泵装置的提水性能。将旋动射流理论与射流泵装置的基本原理相结合,采用圆柱坐标设计方法,确定旋流式射流泵的固定导叶数z=2,导叶高度hv=100mm,工作水入流角α=40°,导叶厚度d1=1mm,导叶宽度d2=10mm。完成旋流式射流泵的初步结构设计。(2)选择面积比m分别为4.37、3.13和2.35的旋流式射流泵和与之面积比相对应的无旋射流泵进行试验对比研究。结果表明,选定面积比中,旋流式射流泵最优面积比2.35,小于无旋射流泵最优面积比3.13,即旋流式射流泵最优面积比有减小趋势;旋流式射流泵装置处于高效运行区时的流量比范围大于无旋射流泵装置;相同面积比下,且运行工况相同时,旋流式射流泵的压力损失较小,性能较优,表现为其压力比最高能够提高0.01,相当于无旋射流泵压力比的5%~10%,其装置效率最高能够提高4%,相当于无旋射流泵装置效率的25%左右。(3)研究确定一种数值模拟方法,并采用此方法对不同面积比的旋流式射流泵和无旋射流泵的内部流动进行对比分析。结果表明,与无旋射流泵相比,在相同面积比下,旋流式射流泵的压力损失较小,且其面积比越小,压力损失越小;旋流式射流泵的工作水速度在流经喷嘴之前有所增加,混合水经喷嘴喷出后,在喉管和扩散管段内中心速度的衰减更慢,且面积比越小,其中心速度的衰减越慢;无旋射流泵在扩散管出口与直管段连接处形成明显的回流漩涡,而旋流式射流泵的内部流动则很流畅。数值模拟结果与试验分析结果相符,旋流式射流泵的压力比和效率相比无旋射流泵都有所提高。(4)基于CFD,以旋流式射流泵的压力比和效率作为试验指标,采用四因素三水平的正交试验方案,通过极差分析和方差分析,对旋流式射流泵的结构尺寸进行优化,并研究其结构尺寸对试验指标的影响规律。结果表明:面积比对两个指标的影响都很显著,固定导叶数、导叶高度和工作水入流角对两个指标的影响都很弱,尤其导叶高度的影响最弱;确定了装置性能较优的旋流式射流泵结构尺寸方案。
[Abstract]:China as a regional water resource distribution is uneven and the serious water shortage in the country, the river water level and groundwater level decreased year by year, resulting in many areas of the height difference of the water level from the ground up to 8m. Jet pump device as a high lift pumping device, the suction up to tens of meters, with reliable work, convenient maintenance. Low cost and shortage in the environment through other dynamic operation and other advantages, but because of the characteristics of the working principle of the device, its performance is poor, low efficiency. Therefore, this paper puts forward improvement on the structure of jet pump, design a fixed guide vane type swirl jet pump, and studied on the device performance, to to improve the performance of jet pump, the main research contents are as follows: (1) the theoretical analysis of the speed and pressure of swirling jet attenuation and its entrainment ability and mixing effects, and the jet theory Applied to the jet pump, the design of a fixed guide vane type swirl jet pump. The results show that the water jet pump weak swirling jets in the radial and axial velocity and pressure of water than strong swirling jet diffusion decay more slowly, the entrainment and mixing ability than in mixed cropping no swirling jet a lot stronger, can help improve the performance of water jet pump lifting device. The basic principle of swirling jet theory and jet pump combined with cylindrical coordinate design method, determine the swirl jet pump vane vane number z=2, height hv=100mm, work flow angle of =40 degrees into the water the guide vane, the thickness of d1=1mm, the preliminary structure design of guide vane width d2=10mm. complete swirl jet pump. (2) choose the area ratio of m were swirling jet pump and 2.35 4.37,3.13 and the area ratio corresponding to the irrotational jet pump was studied. The test results show that the selected Fixed area ratio, swirl jet pump optimal area ratio is less than 2.35, no rotary jet pump optimal area ratio of 3.13, namely the swirl jet pump optimal area ratio decreased; swirl jet pump device in the efficient operation when the flow ratio range is greater than non swirling jet pump device; the same area ratio, and operation conditions are the same, the swirl jet pump with low pressure loss, better performance, as its highest pressure ratio can be increased by 0.01, equivalent to a 5%~10% rotary jet pump pressure ratio, the device can improve the efficiency is the highest of 4%, equivalent to about the efficiency of irrotational jet pump 25%. (3) a numerical study on the simulation method of determining, by using the method of comparative analysis of swirl jet pump with different area ratio and irrotational jet pump internal flow. The results show that, compared with the non rotating jet pump, in the same area ratio, pressure loss of swirling jet pump The loss is small, and the area ratio is smaller, the pressure loss is small; the water velocity in the swirling jet pump increased in the flow through the nozzle, mixing water nozzle, velocity attenuation in the throat and diffuser pipe more slowly, and the area is smaller, the center velocity attenuation is slow; no rotary jet pump in the diffuser outlet formed obvious refluxing swirl and straight pipe joints, and internal flow of swirl jet pump is very smooth. The numerical simulation results and experimental results consistent with the swirl jet pump pressure ratio and efficiency compared to irrotational jet pump are improved. (4) based on CFD. The swirl jet pump pressure ratio and efficiency as the test index, orthogonal experiments of four factors and three levels, through variance analysis, the structure size of the cyclone jet pump were optimized, and study the structural dimensions of the test index The influence of area ratio. The results show that the effect of the two indicators are significant, the number of fixed guide vanes, vane height and water influence of inflow angle on the two indexes are very weak, especially the influence of guide vane height to determine the weakest; swirl jet pump device with better performance of structure size plan.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S277.9

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