界面追踪方法——VOSET(coupled Volume-of-Fluid and Level Set method)结合了VOF和Level Set两种方法的优点,克服了这两种方法的缺点。VOSET方法采用VOF方法捕捉两相间的界面,保持了两相间的质量守恒,克服了Level Set方法质量不守恒...界面追踪方法——VOSET(coupled Volume-of-Fluid and Level Set method)结合了VOF和Level Set两种方法的优点,克服了这两种方法的缺点。VOSET方法采用VOF方法捕捉两相间的界面,保持了两相间的质量守恒,克服了Level Set方法质量不守恒的缺点;利用几何计算方法计算界面附近的Level Set函数,从而可以计算出准确的界面曲率和光顺界面附近突变的物理量,克服了VOF方法利用流体体积函数C计算界面曲率误差较大和光顺界面附近突变的物理量效果较差的缺点,因此该方法较VOF和Level Set方法更加精确。采用VOSET方法对两个及多个气泡的上升和溶并过程进行模拟,分析了复杂两相流动问题中VOSET方法的质量守恒特性、几何计算方法的可行性及求解过程的稳定性。本文的研究工作将为VOSET方法的推广应用奠定基础。展开更多
The pore-scale mechanism of the waterflooding contributes to enhancing oil recovery,which has been widely emphasized in the petroleum industry.In this paper,the performances and accuracy of three tracking interface al...The pore-scale mechanism of the waterflooding contributes to enhancing oil recovery,which has been widely emphasized in the petroleum industry.In this paper,the performances and accuracy of three tracking interface algorithms,including VOF,LS,and VOSET,are compared and analyzed through twophase flow in the conceptual model of pore-throat.The results show that the VOSET method combines the advantages of the other two methods,which not only satisfies the mass conservation but also improves the continuity of the physical quantities near the interface.Then,based on the binary image of the pore,the two-dimensional micro pore model is reconstructed by extracting image contour.The grid independence of the reconstructed pore model is verified by the single-phase flow simulation.The waterflooding process in the reconstructed pore model is simulated using the VOSET method,and the effects of displacement speed and wettability on the oil recovery are analyzed.The morphologies of residual oil under different conditions of wettability are investigated and analyzed.The study provides a basic theory for modeling the pore-scale oil-water flow and optimizing the scheme of the water injection.展开更多
在胶凝原油水力悬浮输送过程中,胶凝原油颗粒在复杂的相间作用力下发生变形。本文基于VOSET方法对胶凝原油颗粒在水力悬浮输送过程中的变形进行模拟研究,颗粒变形后的长短轴通过Image Pro Plus图像处理软件确定,变形的大小用变形度衡量...在胶凝原油水力悬浮输送过程中,胶凝原油颗粒在复杂的相间作用力下发生变形。本文基于VOSET方法对胶凝原油颗粒在水力悬浮输送过程中的变形进行模拟研究,颗粒变形后的长短轴通过Image Pro Plus图像处理软件确定,变形的大小用变形度衡量。模拟结果表明,在水流的剪切作用下圆形的颗粒逐渐发生变形,变形后的原油颗粒接近椭圆形。在给定的模拟条件下,当温度分别为55℃(原油属于牛顿流体)、46℃(原油属于假塑性流体)、40℃(屈服假塑性流体,并呈现胶凝状态)时,原油颗粒的出口变形度分别为59.38%、47.29%、32.47%,胶凝原油颗粒的变形度最小。通过机理分析,明确了胶凝原油颗粒变形受流场的剪切作用、原油的屈服值和剪切稀释性共同影响。展开更多
文摘界面追踪方法——VOSET(coupled Volume-of-Fluid and Level Set method)结合了VOF和Level Set两种方法的优点,克服了这两种方法的缺点。VOSET方法采用VOF方法捕捉两相间的界面,保持了两相间的质量守恒,克服了Level Set方法质量不守恒的缺点;利用几何计算方法计算界面附近的Level Set函数,从而可以计算出准确的界面曲率和光顺界面附近突变的物理量,克服了VOF方法利用流体体积函数C计算界面曲率误差较大和光顺界面附近突变的物理量效果较差的缺点,因此该方法较VOF和Level Set方法更加精确。采用VOSET方法对两个及多个气泡的上升和溶并过程进行模拟,分析了复杂两相流动问题中VOSET方法的质量守恒特性、几何计算方法的可行性及求解过程的稳定性。本文的研究工作将为VOSET方法的推广应用奠定基础。
基金by the National Natural Science Foundation of China(Grant Number 51909225)National Major Science and Technology Projects of China(Grant Number 2017ZX05013001-002)Open research fund of CNPC(grant No.2018A-0908),and the Natural Science Foundation of SWUST(Grant Number 20zx7129).
文摘The pore-scale mechanism of the waterflooding contributes to enhancing oil recovery,which has been widely emphasized in the petroleum industry.In this paper,the performances and accuracy of three tracking interface algorithms,including VOF,LS,and VOSET,are compared and analyzed through twophase flow in the conceptual model of pore-throat.The results show that the VOSET method combines the advantages of the other two methods,which not only satisfies the mass conservation but also improves the continuity of the physical quantities near the interface.Then,based on the binary image of the pore,the two-dimensional micro pore model is reconstructed by extracting image contour.The grid independence of the reconstructed pore model is verified by the single-phase flow simulation.The waterflooding process in the reconstructed pore model is simulated using the VOSET method,and the effects of displacement speed and wettability on the oil recovery are analyzed.The morphologies of residual oil under different conditions of wettability are investigated and analyzed.The study provides a basic theory for modeling the pore-scale oil-water flow and optimizing the scheme of the water injection.
文摘在胶凝原油水力悬浮输送过程中,胶凝原油颗粒在复杂的相间作用力下发生变形。本文基于VOSET方法对胶凝原油颗粒在水力悬浮输送过程中的变形进行模拟研究,颗粒变形后的长短轴通过Image Pro Plus图像处理软件确定,变形的大小用变形度衡量。模拟结果表明,在水流的剪切作用下圆形的颗粒逐渐发生变形,变形后的原油颗粒接近椭圆形。在给定的模拟条件下,当温度分别为55℃(原油属于牛顿流体)、46℃(原油属于假塑性流体)、40℃(屈服假塑性流体,并呈现胶凝状态)时,原油颗粒的出口变形度分别为59.38%、47.29%、32.47%,胶凝原油颗粒的变形度最小。通过机理分析,明确了胶凝原油颗粒变形受流场的剪切作用、原油的屈服值和剪切稀释性共同影响。
