Bromide and herbicide transport under steady‐state and transient flow conditions

Over the past few decades, due to the special features (i.e., easily produced, large-surface-area-to-volume ratio, and engineered particles with designed surface properties), nanoparticles have not only attracted great attentions from the oil and gas industry but also had various applications from drilling and completion, reservoir characterization, to enhanced oil recovery (EOR). As sensors or EOR agents, thus, fate and behavior of nanoparticles in porous media are essential and need to be investigated thoroughly. Nevertheless, most of the published review papers focus on particle transport in saturated porous media, and all of them are about steady-state flow conditions. So far, no attempts have been extended to systematically review current knowledge about nanoparticle transport in porous media with single-phase and two-phase flow systems under both steady-state and unsteady-state conditions. Accordingly, this review will discuss nanoparticle transport phenomena in porous media with its focus on the filtration mechanisms, the underlying interaction forces, and factors dominating nanoparticle transport behavior in porous media. Finally, mathematical models used to describe nanoparticle transport in porous media for both single-phase flow and two-phase flow under steady-state and transient flow conditions will be summarized, respectively.

Download Full-text

Modelling solid transport in building drainage systems

Water Science & Technology ◽

10.2166/wst.1996.0164 ◽

1996 ◽

Vol 33 (9) ◽

pp. 9-16 ◽

Cited By ~ 4

Author(s):

John A. Swaffield ◽

John A. McDougall

Keyword(s):

Decision Making ◽

Boundary Conditions ◽

Numerical Solution ◽

Water Conservation ◽

Transient Flow ◽

Drainage System ◽

System Model ◽

Flow Depth ◽

Flow Conditions ◽

Solid Transport

The transient flow conditions within a building drainage system may be simulated by the numerical solution of the defining equations of momentum and continuity, coupled to a knowledge of the boundary conditions representing either appliances discharging to the network or particular network terminations. While the fundamental mathematics has long been available, it is the availability of fast, affordable and accessible computing that has allowed the development of the simulations presented in this paper. A drainage system model for unsteady partially filled pipeflow will be presented in this paper. The model is capable of predicting flow depth and rate, and solid velocity, throughout a complex network. The ability of such models to assist in the decision making and design processes will be shown, particularly in such areas as appliance design and water conservation.

Download Full-text

Flow monitoring and permeability measurement under constant and transient flow conditions

Composites Science and Technology ◽

10.1016/j.compscitech.2003.10.005 ◽

2004 ◽

Vol 64 (9) ◽

pp. 1239-1249 ◽

Cited By ~ 12

Author(s):

E. Heardman ◽

C. Lekakou ◽

M.G. Bader

Keyword(s):

Transient Flow ◽

Flow Conditions ◽

Permeability Measurement ◽

Flow Monitoring

Download Full-text

Pressure Analysis in the Draft Tube of a Pump-Turbine under Steady and Transient Conditions

Energies ◽

10.3390/en14164732 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4732

Author(s):

Jing Yang ◽

Yue Lv ◽

Dianhai Liu ◽

Zhengwei Wang

Keyword(s):

Steady State ◽

Pressure Pulsation ◽

Transient Flow ◽

Draft Tube ◽

Simulation Method ◽

Wall Pressure ◽

Pump Turbine ◽

Steady State Condition ◽

Transient Conditions ◽

Pumped Storage

Pumped-storage power stations play a regulatory role in the power grid through frequent transition processes. The pressure pulsation in the draft tube of the pump-turbine under transient processes is important for safe operation, which is more intense than that in the steady-state condition. However, there is no effective method to obtain the exact pressure in the draft tube in the transient flow field. In this paper, the pressure in the draft tube of a pump-turbine under steady-state and transient conditions are studied by means of CFD. The reliability of the simulation method is verified by comparing the real pressure pulsation data with the test results. Due to the distribution of the pressure pulsation in the draft tube being complex and uneven, the location of the pressure monitoring points directly affects the accurate judgement of cavitation. Eight monitoring surfaces were set in the straight cone of the draft tube and nine monitoring points were set on each monitoring surface to analyze the pressure differences on the wall and inside the center of the draft tube. The relationships between the pressure pulsation value inside the center of the draft tube and on the wall are studied. The “critical” wall pressure pulsation value when cavitation occurs is obtained. This study provides references for judging cavitation occurrences by using the wall pressure pulsation value in practical engineering.

Download Full-text

Drawing of Tubes

Journal of Applied Mechanics ◽

10.1115/1.3153783 ◽

1980 ◽

Vol 47 (4) ◽

pp. 736-740 ◽

Cited By ~ 14

Author(s):

D. Durban

Keyword(s):

Exact Solution ◽

Steady State ◽

Radial Flow ◽

Material Behavior ◽

Wall Friction ◽

Flow Rule ◽

Flow Conditions ◽

Steady State Flow ◽

Linear Hardening ◽

Von Mises

The process of the tube drawing between two rough conical walls is analyzed within the framework of continuum plasticity. Material behavior is modeled as rigid/linear-hardening along with the von-Mises flow rule. Assuming a radial flow pattern and steady state flow conditions it becomes possible to obtain an exact solution for the stresses and velocity. Useful relations are derived for practical cases where the nonuniformity induced by wall friction is small. A few restrictions on the validity of the results are discussed.

Download Full-text

The Effect of Stator-Rotor Hub Sealing Flow on the Mainstream Aerodynamics of a Turbine

Volume 6: Turbomachinery, Parts A and B ◽

10.1115/gt2006-90838 ◽

2006 ◽

Cited By ~ 24

Author(s):

Kevin Reid ◽

John Denton ◽

Graham Pullan ◽

Eric Curtis ◽

John Longley

Keyword(s):

Steady State ◽

Entropy Generation ◽

Flow Rate ◽

Three Dimensional ◽

Secondary Flows ◽

Flow Conditions ◽

Turbine Efficiency ◽

Turbine Performance ◽

Mainstream Flow ◽

Flow Interactions

An investigation into the effect of stator-rotor hub gap sealing flow on turbine performance is presented. Efficiency measurements and rotor exit area traverse data from a low speed research turbine are reported. Tests carried out over a range of sealing flow conditions show that the turbine efficiency decreases with increasing sealant flow rate but that this penalty is reduced by swirling the sealant flow. Results from time-accurate and steady-state simulations using a three-dimensional multi-block RANS solver are presented with particular emphasis paid to the mechanisms of loss production. The contributions toward entropy generation of the mixing of the sealant fluid with the mainstream flow and of the perturbed rotor secondary flows are assessed. The importance of unsteady stator wake/sealant flow interactions is also highlighted.

Download Full-text