旋转超音速两相凝结流动及实验性能研究

发布时间：2018-07-23 16:30

【摘要】：超音速旋流冷凝分离器作为一种新型天然气净化装置,集低温冷凝和旋流分离于一体,具有结构紧凑,投资费用少,能耗较低和无污染等优点；气体在超音速段的最低压力低于出口压力,温度低于在同一压比下透平膨胀机所能达到的制冷温度,等熵效率高。本文以降低压力能量损失以及使其适用于低压工况为目的,针对超音速冷凝旋流分离器结构设计、含湿气体在喷管内的凝结特性和气液两相流动以及提高装置分离性能的方法进行探索。论文的主要研究工作和结论如下：(1)基于一维变截面等熵流动的理论知识和数值计算软件,设计了一套适用于较低进口压力的超音速冷凝旋流分离器,确定了结构参数和操作参数对装置内部流动特性的影响,实现了进口压力为0.14 MPa时,喷管扩张段内静温均在250 K以下,最低静温达到231 K,且整个装置内并没有出现强激波。(2)建立并验证了含湿气体非平衡自发凝结流动的欧拉双流体模型,研究了操作参数和结构参数对含湿气体凝结特性的影响。结果表明,当进出口压比为1.4,进口温度为300 K,进口相对湿度为0.6,面积比为1.266时,喷管内液滴直径达到最大值1.12μm,此时的成核率为7.5×1018m3/s。(3) 结合VOF模型建立和验证了超音速冷凝旋流分离器内气液两相流动过程的数值模型,研究了液膜与喷管内超音速流动之间的相互影响。研究结果表明,在高速气流的剪切作用下,液膜的厚度沿喷管轴向逐渐变薄,液膜表面速度逐渐增大；同时,液膜破坏了喷管内的超音速流动状态。(4)设计并加工了一套超音速冷凝旋流分离装置,搭建实验平台,研究了实验装置在不同操作参数和结构参数下的分离性能。实验结果表明,增大进出口压比和旋流器出口角,装置分离效率先增大后降低。排液腔结构形式和倾角对装置的分离效率也有很大的影响,(α)型排液腔的分离性能明显优于(ｂ)型排液形式；随着排液腔倾角的增大,装置的分离效率逐渐降低。
[Abstract]:As a new type of natural gas purification device, supersonic cyclone condenser has the advantages of compact structure, low investment cost, low energy consumption and no pollution. The lowest pressure of the gas at supersonic speed is lower than the outlet pressure, and the temperature is lower than the refrigeration temperature of the turbine expander at the same pressure ratio, and the Isentropic efficiency is high. In order to reduce pressure energy loss and make it suitable for low pressure working conditions, the structure design of supersonic condensing cyclone separator is presented in this paper. The condensation characteristics of wet gas in the nozzle, the gas-liquid two-phase flow and the methods to improve the separation performance of the device were explored. The main research work and conclusions are as follows: (1) based on the theoretical knowledge of one-dimensional isentropic flow with variable cross-section and numerical calculation software, a supersonic condensing cyclone separator suitable for lower inlet pressure is designed. The influence of structure parameters and operation parameters on the flow characteristics of the device is determined. When the inlet pressure is 0. 14 MPa, the static temperature in the nozzle expansion section is below 250K. The minimum static temperature is 231K and there is no strong shock wave in the whole unit. (2) the Euler two-fluid model of non-equilibrium spontaneous condensation flow of moist gas is established and verified, and the effects of operation parameters and structural parameters on the condensation characteristics of wet gas are studied. The results show that when the inlet / outlet pressure ratio is 1.4, the inlet temperature is 300K, the import relative humidity is 0.6, the area ratio is 1.266, The maximum diameter of droplet in nozzle is 1.12 渭 m, and the nucleation rate is 7.5 脳 1018 m3 / s. (3) the numerical model of gas-liquid two-phase flow in supersonic condensing cyclone separator is established and verified with VOF model. The interaction between liquid film and supersonic flow in nozzle is studied. The results show that the thickness of liquid film becomes thinner along the axial direction of nozzle and the surface velocity of liquid film increases gradually under the shear action of high velocity airflow. The liquid film destroys the supersonic flow state in the nozzle. (4) A supersonic condensing cyclone separation device is designed and manufactured. The experimental platform is built and the separation performance of the experimental device under different operating and structural parameters is studied. The experimental results show that the separation efficiency increases first and then decreases with increasing the inlet / outlet pressure ratio and the outlet angle of the hydrocyclone. (a) the separation performance of the (伪) type cavity is obviously better than that of the (b) type, and the separation efficiency decreases gradually with the increase of the inclined angle of the outlet cavity.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ051.8

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