scholarly journals Modeling and analysis of the acidizing process in carbonate rocks using a two-phase thermal-hydrologic-chemical coupled model

2019 ◽  
Vol 207 ◽  
pp. 215-234 ◽  
Author(s):  
Piyang Liu ◽  
Xia Yan ◽  
Jun Yao ◽  
Shuyu Sun
Keyword(s):  
Carbonate Rocks ◽  
Coupled Model ◽  
Two Phase ◽  
Modeling And Analysis

Single and two-phase flow modeling and analysis of a coaxial vacuum tube solar collector

Solar Energy ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 175-189 ◽  
Author(s):  
Abdul Waheed Badar ◽  
Reiner Buchholz ◽  
Felix Ziegler
Keyword(s):  
Solar Collector ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Modeling ◽  
Two Phase ◽  
Vacuum Tube ◽  
Modeling And Analysis

Modeling and Analysis of Gear-Shifting Process of Motor-Transmission Coupled Drive System

2016 ◽  
Vol 11 (2) ◽  
Author(s):  
Hongxu Chen ◽  
Xiaoxiao Cheng ◽  
Guangyu Tian
Keyword(s):  
Rotational Speed ◽  
Hybrid Electric Vehicles ◽  
Drive System ◽  
Bench Test ◽  
Control Parameters ◽  
State Variables ◽  
Two Phase ◽  
Performance Simulation ◽  
Modeling And Analysis ◽  
Input Shaft

Motor-transmission coupled drive system is attractive for battery and hybrid electric vehicles. In such a system, the motor rotor is directly connected to the transmission input shaft and the active-synchronization technique is implemented to assist the speed synchronization; therefore, the gear-shifting characteristics are different from those of traditional manual and automated mechanical transmissions. In this work, we present a methodology for modeling the gear-shifting process and analyzing its characteristics in a motor-transmission coupled drive system. We treat the engaging of sleeve and desired clutch gear as a two-phase process—sleeve first interacting with synchro ring and then with clutch gear, respectively, and investigate all possible interaction ways in each phase. The movement of each part is governed by multibody dynamics, and the speed jumps caused by shifting impacts are described using the Poisson coefficient of restitution. We then develop a hybrid automaton (HA) model to couple the continuous-time evolutions and the discrete transitions of state variables, which cover all interaction ways of sleeve, synchro ring, and clutch gear. Based on this model, we carry out simulations in matlab to analyze the effects of two control parameters—the relative rotational speed of sleeve and desired clutch gear, and the shifting force—on shifting performance. Simulation and bench test results show that the optimal control parameters are located in the domain where the relative rotational speed is negative with small absolute value, which means the sleeve will not be locked out by synchro ring and can engage with the desired clutch gear smoothly.

Experimental Study and History-Match of Near-Miscible WAG Coreflood Experiments on Mixed-Wet Carbonate Rocks

2021 ◽  
Author(s):  
Mohamed Mehdi El Faidouzi
Keyword(s):  
Relative Permeability ◽  
Carbonate Rocks ◽  
Hysteresis Model ◽  
Relative Permeabilities ◽  
Two Phase ◽  
Recovery Method ◽  
Phase Displacement ◽  
Three Phase ◽  
Displacement Experiments ◽  
Phase Water

Abstract Water-alternating-gas (WAG) injection, both miscible and immiscible, is a widely used enhanced oil recovery method with over 80 field cases. Despite its prevalence, the numerical modeling of the physical processes involved remains poorly understood, and existing models often lack predictability. Part of the complexity stems from the component exchange between gas and oil and the hysteretic relative permeability effects. Thus, improving the reliability of numerical models requires the calibration of the equation of state (EOS) against phase behavior data from swelling/extraction and slim-tube tests, and the calibration of the three-phase relative permeability model against WAG coreflood experiments. This paper presents the results and interpretation of a complete set of two-phase and thee-phase displacement experiments on mixed-wet carbonate rocks. The three-phase WAG experiments were conducted on the same composite core at near-miscible reservoir condition; experiments differ in the injection order and length of their injection cycles. First, the two-phase water/oil and gas/oil displacement experiments and first cycles of WAG were used to estimate the two-phase relative permeabilities. Then, a synchronized history-matching procedure over the full set of WAG experiments and cycles was carried out to tune Larsen ans Skauge WAG hysteresis model—namely the Land gas traping parameter, the gas reduction exponent, the residual oil reduction factor and three-phase water relative permeability. The second part of this paper deals with the multiphase upscaling of microscopic displacement properties from plug to coarse grid reservoir scale. The two-phase relative permeability curves and three-phase WAG parameters were upscaled using a sector model to preserve the displacement process and reservoir performance. The result of the coreflood calibration indicate that the two-phase displacement and first cycles of WAG yield a consistent set of two-phase relative permeabilities. Including the full set of WAG experiments allowed a robust calibration of the hysteresis model.

scholarly journals VOF Modeling and Analysis of the Segmented Flow in Y-Shaped Microchannels for Microreactor Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Xian Wang ◽  
Hiroyuki Hirano ◽  
Gongnan Xie ◽  
Ding Xu
Keyword(s):  
Surface Force ◽  
Segment Length ◽  
Flow Mode ◽  
Segmented Flow ◽  
Two Phase ◽  
Immiscible Liquids ◽  
Modeling And Analysis ◽  
Transfer Rates ◽  
Phase Liquid ◽  
Simulated Flow

Microscaled devices receive great attention in microreactor systems for producing high renewable energy due to higher surface-to-volume, higher transport rates (heat or/and mass transfer rates), and other advantages over conventional-size reactors. In this paper, the two-phase liquid-liquid flow in a microchannel with various Y-shaped junctions has been studied numerically. Two kinds of immiscible liquids were injected into a microchannel from the Y-shaped junctions to generate the segment flow mode. The segment length was studied. The volume of fluid (VOF) method was used to track the liquid-liquid interface and the piecewise-liner interface construction (PLIC) technique was adopted to get a sharp interface. The interfacial tension was simulated with continuum surface force (CSF) model and the wall adhesion boundary condition was taken into consideration. The simulated flow pattern presents consistence with our experimental one. The numerical results show that a segmented flow mode appears in the main channel. Under the same inlet velocities of two liquids, the segment lengths of the two liquids are the same and depend on the inclined angles of two lateral channels. The effect of inlet velocity is studied in a typical T-shaped microchannel. It is found that the ratio between the lengths of two liquids is almost equal to the ratio between their inlet velocities.

scholarly journals Full Scope Modeling and Analysis on the Secondary Circuit of Chinese Large-Capacity Advanced PWR Based on RELAP5 Code

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Dao-gang Lu ◽  
Fan Zhang ◽  
Dan-ting Sui ◽  
Xue-zhang Xi ◽  
Lei-bo Yu
Keyword(s):  
Nuclear Power ◽  
Peak Load ◽  
Severe Accident ◽  
Secondary Circuit ◽  
Two Phase ◽  
Large Capacity ◽  
Modeling And Analysis ◽  
Heat Transfer Efficiency ◽  
Design Values ◽  
Under Construction

Chinese large-capacity advanced PWR under construction in China is a new and indispensable reactor type in the developing process of NPP fields. At the same time of NPP construction, accident sequences prediction and operators training are in progress. Since there are some possible events such as feedwater pumps trip in secondary circuit may lead to severe accident in NPP, training simulators and engineering simulators of CI are necessary. And, with an increasing proportion of nuclear power in China, NPP will participate in regulating peak load in power network, which requires accuracy calculation and control of secondary circuit. In order to achieve real-time and full scope simulation in the power change transient and accident scenarios, RELAP5/MOD 3.4 code has been adopted to model the secondary circuit for its advantage of high calculation accuracy. This paper describes the model of steady state and turbine load transient from 100% to 40% of secondary circuit using RELAP5 and provides a reasonable equivalent method to solve the calculation divergence problem caused by dramatic two-phase condition change while guaranteeing the heat transfer efficiency. The validation of the parameters shows that all the errors between the calculation values and design values are reasonable and acceptable.

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