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Robert A Handler - One of the best experts on this subject based on the ideXlab platform.

  • direct numerical simulation of the turbulent channel flow of a Polymer Solution
    Physics of Fluids, 1997
    Co-Authors: R Sureshkumar, Antony N Beris, Robert A Handler
    Abstract:

    In this work, we present from first principles a direct numerical simulation (DNS) of a fully turbulent channel flow of a dilute Polymer Solution. The Polymer chains are modeled as finitely extensible and elastic dumbbells. The simulation algorithm is based on a semi-implicit, time-splitting technique which uses spectral approximations in the spatial coordinates. The computations are carried out on a CRAY T3D parallel computer. The simulations are carried out under fully turbulent conditions albeit, due to computational constraints, not at as high Reynolds number as that usually encountered in Polymer-induced drag reduction experiments. In order to compensate for the lower Reynolds number, we simulate more elastic fluids than the ones encountered in drag reduction experiments resulting in Weissenberg numbers (a dimensionless number characterizing the flow elasticity) of similar magnitude. The simulations show that the Polymer induces several changes in the turbulent flow characteristics, all of them consi...

R Sureshkumar - One of the best experts on this subject based on the ideXlab platform.

  • direct numerical simulation of the turbulent channel flow of a Polymer Solution
    Physics of Fluids, 1997
    Co-Authors: R Sureshkumar, Antony N Beris, Robert A Handler
    Abstract:

    In this work, we present from first principles a direct numerical simulation (DNS) of a fully turbulent channel flow of a dilute Polymer Solution. The Polymer chains are modeled as finitely extensible and elastic dumbbells. The simulation algorithm is based on a semi-implicit, time-splitting technique which uses spectral approximations in the spatial coordinates. The computations are carried out on a CRAY T3D parallel computer. The simulations are carried out under fully turbulent conditions albeit, due to computational constraints, not at as high Reynolds number as that usually encountered in Polymer-induced drag reduction experiments. In order to compensate for the lower Reynolds number, we simulate more elastic fluids than the ones encountered in drag reduction experiments resulting in Weissenberg numbers (a dimensionless number characterizing the flow elasticity) of similar magnitude. The simulations show that the Polymer induces several changes in the turbulent flow characteristics, all of them consi...

Xing-liang Song - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Separate Layer Injection Technique for Polymer Flooding in Daqing Oil Field
    Proceedings of the International Field Exploration and Development Conference 2018, 2020
    Co-Authors: Shao-gong Zhu, Wang-fu Zhou, Chong-jiang Liu, Xing-liang Song, Hai-cheng Li, Guang-lei Gao, Jun-dong Tang, Jing Wang
    Abstract:

    Daqing Oil Field is the largest continental oil field in China. It is a large heterogeneous sandstone oil field with various permeability layers in longitudinal. Polymer flooding plays an important role in Daqing Oil Field which has recovered 10 million tons oil per year for 11 years. In the process of commingled Polymer injection, most of the Solution enters high permeability layers. Consequently, low permeability layers cannot be swept effectively which limits the recovery rate of Polymer flooding. Based on the successful experiences of separate layer water flooding technology applied in Daqing Oil Field, several separate layer Polymer flooding techniques were developed. The purpose of this technology is to inject Polymer Solution into pay zones separately with different pressure and flow rate according to reservoir properties, getting a stable injection profile of Polymer Solution in longitudinal direction so as to improve the overall recovery rate. The key points of this technology lie in three respects: First, the injected Polymer Solution should have a stable flow rate and pressure difference in the whole duration of Polymer flooding. Second, the injected Polymer Solution should keep a higher viscosity to ensure EOR result of Polymer flooding. Thirdly, the economic factor must be considered. This paper presents a unique separate Polymer injection technology which solves the above issues effectively. The injected nozzle is designed into a special streamline style with different stages. When Polymer Solution flows through the nozzle, the molecular chains of Polymer will expand and contract, creating an additional pressure difference. The more stages it has, the higher pressure difference can be reached. Furthermore, the shape of nozzle is optimized by simulation tools to ensure the minimum viscosity loss of Polymer Solution during the injection. After the optimal design, the maximum additional pressure difference of this nozzle can reach 2.5 MPa at the injection flowrate of 50 m^3/d as well as viscosity loss ratio is less than 6%. This technology has been applied in 6464 wells in Daqing Oil Field. The producing degree of reserve was improved from 62.8 to 74.7% and oil recovery rate was improved by 2%. It is a remarkable core technology for sandstone oil fields in Polymer flooding period. This technology has a brilliant future in the development of mature oil field.

  • Viscosity loss of the flow of Polymer Solution through separate layer injection allocation with nozzle and jet target
    2009 IEEE 10th International Conference on Computer-Aided Industrial Design & Conceptual Design, 2009
    Co-Authors: Xing-liang Song, Fumin Liang
    Abstract:

    Based on dimensional analysis theory, the criterion equation of the flow of Polymer Solution through separate layer injection allocation of cylindrical cavity with a nozzle and a jet target is established; the viscosity loss regression formulae of the flow of Polymer Solution through separate layer injection allocation of cylindrical cavity with a nozzle and a jet target are obtained through regression analysis by SAS software; the curves of viscosity loss ratio versus flow rate, target distance and nozzle diameter are ploted, and the behavior of viscosity loss ratio curves is analyzed.

Victor Steinberg - One of the best experts on this subject based on the ideXlab platform.

  • elastic turbulence in a Polymer Solution flow
    Nature, 2000
    Co-Authors: Alex Groisman, Victor Steinberg
    Abstract:

    Turbulence is a ubiquitous phenomenon that is not fully understood. It is known that the flow of a simple, newtonian fluid is likely to be turbulent when the Reynolds number is large (typically when the velocity is high, the viscosity is low and the size of the tank is large1,2). In contrast, viscoelastic fluids3 such as Solutions of flexible long-chain Polymers have nonlinear mechanical properties and therefore may be expected to behave differently. Here we observe experimentally that the flow of a sufficiently elastic Polymer Solution can become irregular even at low velocity, high viscosity and in a small tank. The fluid motion is excited in a broad range of spatial and temporal scales, and we observe an increase in the flow resistance by a factor of about twenty. Although the Reynolds number may be arbitrarily low, the observed flow has all the main features of developed turbulence. A comparable state of turbulent flow for a newtonian fluid in a pipe would have a Reynolds number as high as 105 (refs 1, 2). The low Reynolds number or ‘elastic’ turbulence that we observe is accompanied by significant stretching of the Polymer molecules, resulting in an increase in the elastic stresses of up to two orders of magnitude.

Karl F Freed - One of the best experts on this subject based on the ideXlab platform.