Study of slip velocity and application of drift-flux model to slip velocity in a liquid–solid circulating fluidized bed

2011 ◽  
Vol 22 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Natarajan Palani ◽  
Velraj Ramalingam ◽  
G. Ramadoss ◽  
R.V. Seeniraj
Keyword(s):  
Fluidized Bed ◽  
Slip Velocity ◽  
Circulating Fluidized Bed ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flux Model

APPLICATION OF DRIFT-FLUX MODEL IN LIQUID-SOLID CIRCULATING FLUIDIZED BED

2008 ◽  
Vol 195 (9) ◽  
pp. 1144-1158 ◽  
Author(s):  
P. Natarajan ◽  
R. Velraj ◽  
R. V. Seeniraj
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flux Model

Dynamic Cuttings Slip Velocity Evaluation in Non-Newtonian Fluids Using a Temperature Dependent Transient Drift-Flux Model for Directional Wells

2018 ◽  
Author(s):  
Ekaterina Wiktorski ◽  
Dan Sui ◽  
Kjell Kåre Fjelde ◽  
Vebjørn Langåker
Keyword(s):  
Numerical Scheme ◽  
Slip Velocity ◽  
Newtonian Fluids ◽  
Experimental Results ◽  
Velocity Variation ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flux Model

The objective of drilling a well is to prepare a clean hole without obstructions for further casing and production tubing running. Cuttings transport has always been important, but challenging process, especially when drilling long directional wells. Poor hole cleaning causes severe problems, as stuck pipe, extreme torque and drag, difficulties in casing landing, cementing, etc. Extensive studies of cuttings transport, both theoretical and experimental, have been performed to estimate, for example, cuttings concentration and cuttings slip velocity to determine optimal conditions for effective hole cleaning. This paper presents a dynamic analysis of cuttings transport in non-Newtonian fluids based on a transient drift-flux model and an associated numerical scheme AUSMV (advection upstream splitting method) developed by Evje and Fjelde 2002. In this paper, the scheme is modified to simulate cuttings transport dynamically taking into account effects related to pressure, temperature and cuttings slip. During drilling, the heat is transported from the formation into the wellbore and up to the surface. In this paper, the energy balance is enhanced by introducing an analytical temperature model into the AUSMV scheme. The temperature distribution along the well is calculated at the beginning of simulation and kept constant throughout the simulation. Additionally, the AUSMV scheme is improved by considering drilling fluid’s transport- and thermal properties. Transport properties of an oil-based mud, such as viscosity and density, are obtained from experiments. The experimental results were used to determine the coefficients in a linear density model used in the study to investigate the effect of non-Newtonian behavior on the heat transfer, cuttings transport and downhole pressure. Furthermore, a model to calculate the apparent viscosity at various pressures and temperatures was developed based on the experimental results and used to evaluate the impact of viscous forces on the cuttings distribution in the well. Presented numerical scheme solves dynamic cuttings transport problems taking into account the slip velocity variation with wellbore geometry, operational (controllable) parameters and formation properties. In comparison to the traditional steady-state models, the transient cuttings transport model with integrated depth-dependent parameters gives a possibility to achieve a more realistic simulation of cuttings transport, distribution and accumulation along the wellbore through the time.

Interfacial Structures and Regime Transition in Co-Current Downward Bubbly Flow

2004 ◽  
Vol 126 (4) ◽  
pp. 528-538 ◽  
Author(s):  
S. Kim ◽  
S. S. Paranjape ◽  
M. Ishii ◽  
J. Kelly
Keyword(s):  
Two Phase Flow ◽  
Bubbly Flow ◽  
Superficial Velocity ◽  
Phase Flow ◽  
Two Phase ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flow Parameters ◽  
Interfacial Structures ◽  
Flux Model

The vertical co-current downward air-water two-phase flow was studied under adiabatic condition in round tube test sections of 25.4-mm and 50.8-mm ID. In flow regime identification, a new approach was employed to minimize the subjective judgment. It was found that the flow regimes in the co-current downward flow strongly depend on the channel size. In addition, various local two-phase flow parameters were acquired by the multi-sensor miniaturized conductivity probe in bubbly flow. Furthermore, the area-averaged data acquired by the impedance void meter were analyzed using the drift flux model. Three different distributions parameters were developed for different ranges of non-dimensional superficial velocity, defined by the ration of total superficial velocity to the drift velocity.

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