Water-based fracturing fluid has recently garnered increasing attention as an alternative oilfield working for propagating reservoir fractures and transporting sand. However, the low temperature resistance stability of water-based is a significant limitation, restricting fracture propagation gravel transport. To effectively ameliorate sand-carrying capacity, modified cross-linker with properties adaptable to varying conditions functional groups was synthesized chemically characterized....

To circumvent the numerous deficiencies inherent to water-based fracturing fluids and associated greenhouse effect, CO2 are employed as a novel reservoir working fluid for reconstruction in unconventional oil fields. Herein, mathematical model of crack propagation based on seepage–stress–damage coupling was constructed analysing effects different drilling components parameters behaviour low permeability reservoirs. Additionally, fracture expansion mechanism reservoirs elucidated through...

High-speed and high-precision position servo system of permanent magnet synchronous motor (PMSM) is the key part research development manipulator's joint. The active disturbance rejection control (ADRC) one commonly used methods in system, which has advantages fast speed easy physical realization. However, existing ADRC mostly adopts three-loop structure position-speed-current, some problems such as slow positioning response, poor accuracy, load adaptability caused by difficult parameter...

Given the current research gap regarding cavitation phenomena and startup conditions in water-lubricated bearings (WLBs), this study offers an innovative approach by integrating mass conservation boundary condition proposed Jakobsson, Floberg, Olsson (known as JFO condition) with a transient mixed lubrication model of WLBs. It also considers impact elastic deformation surface roughness peaks, thus establishing WLBs that incorporates effect. Furthermore, dynamic behaviors are contrasted...

The mechanism of constant electric field regulation on droplet formation in a T-junction microchannel is investigated numerically, and the law discrete phase fluid behavior different viscosity systems summarized. This research develops two-phase-electrohydrodynamic solver OpenFOAM® framework. uses leaky medium model to simulate microfluidic system volume method trace interface. It found that generation within can be divided into squeeze shear effect, where will have transition under...

Ultrasound and viscosity reducers are commonly used methods to reduce the of heavy oil. In order compare reduction effects ultrasound study their mechanism interaction on oil, molecular dynamics simulation was carried out in this paper. First, a model oil composed asphaltene, resin, aromatic hydrocarbon, saturated hydrocarbon established work. Through simulation, different rate, hydrogen bond number, type, occupation rate were obtained, analyzed. By calculating number bonds five oil-soluble...

To study the lubrication performance of tilting-pad thrust bearing (TPTBs) during start-up in nuclear pump, a hydrodynamic model TPTBs was established based on computational fluid dynamics (CFD) method and fluid-structure interaction (FSI) technique. Further, mesh motion algorithm for transient calculation bearings developed user defined function (UDF). The result demonstrated that minimum film thickness increases first then decreases with rotational speed under condition. influence pad tilt...

As the traditional polymer stabilizer is eliminated to improve injectability of foam in low-permeability reservoirs, stability, plugging capacity, conformance control and oil recovery performance surfactant-alternating-gas (SAG) become significantly important for determining its adaptability permeability heterogeneity, which were focused experimentally researched this paper. Results show that SAG bubbles are highly stable micron-sized channels porous media (than conventional unconstrained...

Purpose The growing demand of efficiency and economy has led to a dramatic increase the operating speed journal bearing, with higher temperature distribution. This paper aims investigate three-dimensional distribution bearings. Design/methodology/approach A thermo-hydrodynamic lubrication model bearing was established based on full 3D CFD method. two-sided wall used include conjugate heat transfer effect. temperature-dependent characteristics cavitation impact were also included. simulation...

The identification of delays and delay compensation are critical problems in real-time hybrid simulations (RTHS). Conventional methods mostly based on the assumption a constant delay. However, system may vary during tests owing to nonlinearity loading and/or behavioral variations specimen. To address this issue, study presents an adaptive method discrete model system. In particular, parameters identified updated online with least-squares represent servo hydraulic Furthermore, model,...

Purpose Surface textures have been widely used in thrust bearings as a means of enhancing the tribological performance. The effect with spiral distribution on lubrication characteristics has not fully covered. This paper aims to investigate and find optimal structure parameters maximum loading capacity minimum friction force goals. Design/methodology/approach Combining multi-objective optimization method based non-dominated sorted genetic algorithm-II response surface methodology, key...

Purpose This study aims to solve the premature failure of rubber stator due wear, reduce frictional resistance moment screw pump problem a model Daqing oilfield oil recovery system shutdown after difficult start. Design/methodology/approach For first time, rotor surface was treated with dot-matrix texture effect dot matrix on tribological performance stator-rotor friction subsets pump. Reciprocating tests different morphologies (S-shape, double tongue) and angular parameters (0°, 45° 90°)...

Abstract In this work, a non-isothermal viscoelastic computational framework is proposed for macroscopic polymer melt filling and mesoscopic spherulite growth. Firstly, the governing equation solved by coupled level set immersed boundary finite-volume (LS-IB-FV) method. The melt-air interface captured level-set volume-of-fluid (CLSVOF) And crystallization behavior predicted phase field model. Then, numerical simulation process compared with experimental one to validate it simulated that...

In this paper, in order to establish the energy separation mechanism of vortex tube, hydrodynamic behavior compressible fluid asymmetric cavity space is investigated, and a numerical model trajectory deflection deduced established; form optimal design method structural parameters force situation microelements entering different regions chamber tube analyzed, equations are corrected by combining with expansion characterizing strength, transportability, initiation characteristics given. The...

This paper compares the effect of different angles triangular conical and truncated regulating valves on heat cold separation vortex tubes. Numerical simulation experimental studies show that60° cone valve has better cooling effect. The inlet pressure is in range 0.2MPa–0.4 MPa, temperature rate change at end tube larger numerical smaller. Under same circumstances, connected to area cold-heat exchange hot end, as well location fluid's stagnation point. merging related angle form valve. data...