胶凝原油管道启动问题中关键非定常参量研究

Study on pipeline restart is quite crucial for safe operation of crude oil pipeline. Exact description of unsteady parameters like rheological properties, compressibility and pressure wave velocity is the key to solving the issue of pipeline restart. The project will carry out flow field analysis on the DIN rheology test system to study the law of velocity distribution of gelled crude oil flowing under the shearing of this system, explore the reliability of conducting initial viscoelastic-thixotropic properties test of gelled oil using this test system and try to find the true viscoelastic-thixotropic properties based on the measured data. The gelled oil ultrasonic wave velocity measuring instrument is used to conduct the test of gelled oil’s bulk modulus within the scope of solid deformation behavior. The uniaxial compression deformation test and volume compression experiments within long axis cylinder compression chamber of gelled oil are carried out and with the help of mechanics of viscoelastic materials, the quantitative description of bulk modulus of gelled oil is researched. Based on the conclusions of true viscoelastic-thixotropic properties and viscoelastic bulk modulus, theoretical analysis is carried out on start-up pressure wave and pipe segment to study the compression deformation-yield-flow law of gelled oil within circular tube, illustrate the mechanism of such phenomenon like attenuation or linked to the start-up conditions of pressure wave and pressure signal. Based on the pipeline restart experiments, the quantitative relation of parameters like pipeline pressure, flow and so on under different start-up boundary conditions is explored. And the scale-up law of applying experimental data to field pipeline with larger diameters is discussed. Achievements of this project could fill up the blank of research on unsteady parameters of pipeline restart and provide important materials to enrich and complete the non-Newtonian fluid mechanics theory.

胶凝原油管道停输再启动是保障含蜡原油管道安全运行的一个核心问题。准确描述胶凝原油流变性、压缩性、管道启动压力波速等非定常参量是研究胶凝原油管道启动问题的关键。.本课题针对DIN流变系统初始旋转阶段存在的测试假象，研究系统内胶凝原油剪切流动分布规律，探索系统非稳态流场与机械过程对胶凝原油初始流变性测试结果的影响，逆向求解胶凝原油真实粘弹-触变特性。开展胶凝原油固体体积弹性模量测试、单轴压缩变形测试、长轴圆筒压缩舱试验，借助粘弹性力学理论，获取胶凝原油粘弹性体积模量表述公式。基于粘弹-触变特性、粘弹性体积模量研究结果，分析胶凝原油圆管内压缩变形-屈服-流动规律，揭示压力波、屈服前锋出现衰减的物理机制，结合管道启动试验，量化启动压力、流量等参数关系。探索室内管路试验应用于大口径管道的放大准则，填补停输再启动问题测算体系中关键非定常参量确定的空白，为丰富和完善非牛顿流体力学理论提供重要材料。

胶凝原油管道停输再启动是保障含蜡原油管道安全运行的一个核心问题。准确描述胶凝原油流变性、压缩性、管道启动压力波速等非定常参量是研究胶凝原油管道启动问题的关键。.本课题针对DIN流变系统初始旋转阶段存在的测试假象，研究系统内胶凝原油剪切流动分布规律，探索系统非稳态流场与机械过程对胶凝原油初始流变性测试结果的影响，逆向求解胶凝原油真实粘弹-触变特性。开展胶凝原油固体体积弹性模量测试、单轴压缩变形测试、长轴圆筒压缩舱试验，借助粘弹性力学理论，获取胶凝原油粘弹性体积模量表述公式。基于粘弹-触变特性、粘弹性体积模量研究结果，分析胶凝原油圆管内压缩变形-屈服-流动规律，揭示压力波、屈服前锋出现衰减的物理机制，结合管道启动试验，量化启动压力、流量等参数关系。探索室内管路试验应用于大口径管道的放大准则，填补停输再启动问题测算体系中关键非定常参量确定的空白，为丰富和完善非牛顿流体力学理论提供重要材料。