scholarly journals The Effect of Heat Transfer and Polymer Concentration on Non-Newtonian Fluid from Pore-Scale Simulation of Rock X-Ray micro-CT

2017 ◽  
Author(s):  
Moussa Tembely ◽  
Ali M. AlSumaiti ◽  
Mohamed S. Jouini ◽  
Khurshed Rahimov
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Newtonian Fluid ◽  
Polymer Concentration ◽  
Isothermal Condition ◽  
Operating Conditions ◽  
Flow Index ◽  
Micro Ct ◽  
Pore Scale ◽  
Fluid Rheology

Most of the pore-scale imaging and simulations of non-Newtonian fluid are based on the simplifying geometry of network modeling and overlook the fluid rheology and heat transfer. In the present paper, we developed a non-isothermal and non-Newtonian numerical model of the flow properties at pore-scale by direct simulation of the 3D micro-CT images using a Finite Volume Method (FVM). The numerical model is based on the resolution of the momentum and energy conservation equations. Owing to an adaptive meshing technique and appropriate boundary conditions, rock permeability and mobility are accurately computed. A temperature and concentration-dependent power-law viscosity model in line with the experimental measurement of the fluid rheology is adopted. The model is first applied at isothermal condition to 2 benchmark samples, namely Fontainebleau sandstone and Grosmont carbonate, and is found to be in good agreement with the Lattice Boltzmann method (LBM). Finally, at non-isothermal conditions, an effective mobility is introduced that enables to perform a numerical sensitivity study to fluid rheology, heat transfer, and operating conditions. While the mobility seems to evolve linearly with polymer concentration, the effect of the temperature seems negligible by comparison. However, a sharp contrast is found between carbonate and sandstone under the effect of a constant temperature gradient. Besides concerning the flow index and consistency factor, a good master curve is derived when normalizing the mobility for both the carbonate and the sandstone.

scholarly journals The Effect of Heat Transfer and Polymer Concentration on Non-Newtonian Fluid from Pore-Scale Simulation of Rock X-ray Micro-CT

Polymers ◽  
2017 ◽  
Vol 9 (12) ◽  
pp. 509 ◽  
Author(s):  
Moussa Tembely ◽  
Ali AlSumaiti ◽  
Mohamed Jouini ◽  
Khurshed Rahimov
Keyword(s):  
Heat Transfer ◽  
Newtonian Fluid ◽  
Polymer Concentration ◽  
Micro Ct ◽  
Pore Scale ◽  
X Ray

Numerical and Experimental Investigation of Interface Bonding Via Substrate Remelting of an Impinging Molten Metal Droplet

1996 ◽  
Vol 118 (1) ◽  
pp. 164-172 ◽  
Author(s):  
C. H. Amon ◽  
K. S. Schmaltz ◽  
R. Merz ◽  
F. B. Prinz
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Molten Metal ◽  
Thermal Stresses ◽  
Initial Conditions ◽  
Metal Droplet ◽  
Solid Substrate ◽  
Numerical Results ◽  
Operating Conditions ◽  
Analytical Approaches

A molten metal droplet landing and bonding to a solid substrate is investigated with combined analytical, numerical, and experimental techniques. This research supports a novel, thermal spray shape deposition process, referred to as microcasting, capable of rapidly manufacturing near netshape, steel objects. Metallurgical bonding between the impacting droplet and the previous deposition layer improves the strength and material property continuity between the layers, producing high-quality metal objects. A thorough understanding of the interface heat transfer process is needed to optimize the microcast object properties by minimizing the impacting droplet temperature necessary for superficial substrate remelting, while controlling substrate and deposit material cooling rates, remelt depths, and residual thermal stresses. A mixed Lagrangian–Eulerian numerical model is developed to calculate substrate remelting and temperature histories for investigating the required deposition temperatures and the effect of operating conditions on remelting. Experimental and analytical approaches are used to determine initial conditions for the numerical simulations, to verify the numerical accuracy, and to identify the resultant microstructures. Numerical results indicate that droplet to substrate conduction is the dominant heat transfer mode during remelting and solidification. Furthermore, a highly time-dependent heat transfer coefficient at the droplet/substrate interface necessitates a combined numerical model of the droplet and substrate for accurate predictions of the substrate remelting. The remelting depth and cooling rate numerical results are also verified by optical metallography, and compare well with both the analytical solution for the initial deposition period and the temperature measurements during droplet solidification.

Pore-Scale Modeling of Non-Newtonian Fluid Flow Through Micro-CT Images of Rocks

2018 ◽  
pp. 363-375
Author(s):  
Moussa Tembely ◽  
Ali M. AlSumaiti ◽  
Khurshed Rahimov ◽  
Mohamed S. Jouini
Keyword(s):  
Fluid Flow ◽  
Newtonian Fluid ◽  
Ct Images ◽  
Micro Ct ◽  
Pore Scale ◽  
Scale Modeling ◽  
Pore Scale Modeling ◽  
Flow Through

Heat Transfer and Entropy Generation Characteristics of a Non-Newtonian Fluid Squeezed and Extruded Between Two Parallel Plates

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
P Kaushik ◽  
Pranab Kumar Mondal ◽  
Sukumar Pati ◽  
Suman Chakraborty
Keyword(s):  
Heat Transfer ◽  
Newtonian Fluid ◽  
Entropy Generation ◽  
Bejan Number ◽  
Engineering Systems ◽  
Power Law Model ◽  
Parallel Plates ◽  
Unsteady Heat Transfer ◽  
Thermodynamic Performance ◽  
Fluid Rheology

This study investigates the unsteady heat transfer and entropy generation characteristics of a non-Newtonian fluid, squeezed and extruded between two parallel plates. In an effort to capture the underlying thermo-hydrodynamics, the power-law model is used here to describe the constitutive behavior of the non-Newtonian fluid. The results obtained from the present analysis reveal the intricate interplay between the fluid rheology and the squeezing dynamics, toward altering the Nusselt number and Bejan number characteristics. Findings from this study may be utilized to design optimal process parameters for enhanced thermodynamic performance of engineering systems handling complex fluids undergoing simultaneous extrusion and squeezing.

Experimental and Numerical Investigation of Heat Transfer Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

2008 ◽  
Author(s):  
Rami Sabbah ◽  
Jamal Yagoobi ◽  
Said Al Hallaj
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Pressure Drop ◽  
Phase Change ◽  
Phase Change Material ◽  
Operating Conditions ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Encapsulated Phase Change Material ◽  
Change Material

This experimental and numerical study investigates Micro-Encapsulated Phase Change Material (MEPCM) heat transfer characteristics and corresponding pressure drop. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.5mm and a length of 1,016mm is selected. A MEPCM mass concentration of 20% slurry with particle diameter ranging between 5–15μm is included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding Nusselt number are determined for various operating conditions. The experimental results are used to validate the numerical model predictions. The numerical model results show good agreement with the experimental data under various operating conditions. The controlling parameters are identified and their effects on the heat transfer characteristics of micro-channels with MEPCM slurries are evaluated.

Entropy Generation Minimization in an Electroosmotic Flow of Non-Newtonian Fluid: Effect of Conjugate Heat Transfer

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Prakash Goswami ◽  
Pranab Kumar Mondal ◽  
Anubhab Datta ◽  
Suman Chakraborty
Keyword(s):  
Heat Transfer ◽  
Newtonian Fluid ◽  
Entropy Generation ◽  
Conjugate Heat Transfer ◽  
Transfer Problem ◽  
Heat Removal ◽  
Entropy Generation Rate ◽  
Fluidic Channel ◽  
Thermal Boundary Conditions ◽  
Fluid Rheology

We investigate the entropy generation characteristics of a non-Newtonian fluid in a narrow fluidic channel under electrokinetic forcing, taking the effect of conjugate heat transfer into the analysis. We use power-law model to describe the non-Newtonian fluid rheology, in an effort to capture the essential thermohydrodynamics. We solve the conjugate heat transfer problem in an analytical formalism using the thermal boundary conditions of third kind at the outer surface of the walls. We bring out the alteration in the entropy generation behavior as attributable to the rheology-driven alteration in heat transfer, coupled with nonlinear interactions between viscous dissipation and Joule heating originating from electroosmotic effects. We unveil optimum values of different parameters, including both the geometric as well as thermophysical parameters, which lead to the minimization of the entropy generation rate in the system. We believe that the inferences obtained from the present study may bear far ranging consequences in the design of various cooling and heat removal devices/systems, for potential use in microscale thermal management.

Numerical simulation of hydrogen arcjet thruster using coupled sheath model

2021 ◽  
Author(s):  
Deepak Akhare ◽  
Hari Prasad Nandyala ◽  
Jayachandran T ◽  
Amit Kumar
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Numerical Model ◽  
Close Agreement ◽  
Operating Conditions ◽  
Input Current ◽  
Arc Length ◽  
Electron Current ◽  
Ion Diffusion ◽  
Conduction Heat Transfer

Abstract In the present work, a complete 2D chemical and thermal non-equilibrium numerical model coupled with a relatively simple sheath model is developed for hydrogen arcjet thruster. Conduction heat transfer in the anode wall is also included in the model. The operating voltages predicted by the model are compared with those in the literature and are found to be in close agreement. Power distributions for the various operating conditions are obtained, anode radiation loss primarily determines the thruster efficiency. Higher thruster efficiency was found to be associated with longer arc length. At cathode ion diffusion contribution dominates except at low input current where thermo-field electron current is dominant.

A Numerical Model to Investigate Evaporative Condensers Behaviour at Tube Scale

2014 ◽  
Author(s):  
Maria Fiorentino ◽  
Giuseppe Starace
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Transfer Coefficient ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Multiphase Model ◽  
Transfer Coefficients ◽  
Single Tube ◽  
Water Vaporization

Evaporative condensers operate at lower temperatures and with a higher efficiency compared to air condensers, as heat rejection is limited by air wet bulb temperature and mainly caused by water vaporization. This reduces the compressor pressure-lift and improves refrigeration cycle performance. Due to complex phenomena of heat and mass transfer on the tube bundles, modeling the evaporative condensers is a hard task and fine grids in numerical simulations are requested to reach acceptable results. A two-dimensional steady state numerical model at the single tube scale has been developed in Ansys-Fluent (release- 14.5), adopting the VOF multiphase model. Moist air has been treated as a mixture of air and water vapor species, while water vaporization and latent heat have been modeled with a C++ User Defined Function. The tube wall temperature has been assumed constant. The aim of this work is to describe the developed numerical model and to validate it by comparing results obtained at different operating conditions with empirical relationships found in the literature in terms of combined and overall heat transfer coefficients. Combined heat transfer coefficient variation along the tube surface has been analyzed, observing that the heat transfer coefficient is higher in the impingement zone, becomes approximately uniform and rises approaching the trailing edge. Moisture content distributions at different sections through the heat exchanger have been examined in detail as well. This study will be the basis to investigate the performance of the whole condenser taking into account the real evolution of the operating conditions of each single tube in the bundle, whatever its arrangement.

Thermal Effects in Thrust Washer Lubrication

2001 ◽  
Vol 124 (1) ◽  
pp. 166-177 ◽  
Author(s):  
To Him Yu ◽  
Farshid Sadeghi
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Effects ◽  
Groove Depth ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Frictional Torque ◽  
Time Step ◽  
Transfer Equations ◽  
Side Flow

A numerical model was developed to study the thermal effects on the lubrication mechanism of radially-grooved thrust washers. A mass-conserving transient thermohydrodynamic (THD) analysis was performed by solving the modified Reynolds and energy equations for the lubricant pressure and temperature distributions. The heat transfer equations were also solved simultaneously to obtain the temperature fields of the solids (thrust washers). Due to different thermal time responses of the lubricant film and the solids, heat transfer equations of the runner and the thrust washer pad were treated as in quasi-steady state at each time step in the transient solution. Elrod cavitation algorithm was implemented to include lubricant cavitation. The results show that thermal effects do not only reduce load carrying capacity and the frictional torque but also increase side flow rate. Moreover, the numerical model also demonstrates that the thermal effects have greater influence on the load support when the groove depth and groove numbers increase. Furthermore, the analytical results also show that there exists certain operating conditions before thermal effects become the dominating factors in influencing the thrust washer performance.

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