Buoyant Convective Flow and Heat Dissipation of Cu–H2O Nanoliquids in an Annulus Through a Thin Baffle

2021 ◽  
Vol 10 (2) ◽  
pp. 292-304
Author(s):  
B. V. Pushpa ◽  
M. Sankar ◽  
F. Mebarek-Oudina
Keyword(s):  
Thermal Transport ◽  
Convective Flow ◽  
Heat Dissipation ◽  
Numerical Technique ◽  
System Of Equations ◽  
Physical Processes ◽  
Transport Enhancement ◽  
Rayleigh Numbers ◽  
Base Liquid ◽  
Selection Of

This article numerically investigates the buoyant convective flow and thermal transport enhancement of Cu–H2O nanoliquid in a differentially heated upright annulus having a thin baffle. For the analysis, the outer and inner cylinders are cooled and heated respectively through insulated top and lower boundaries. Also, the baffle temperature is assumed to be that of the hot cylinder. The finite difference based numerical technique is used to solve the system of equations governing the physical processes. The findings are accessible in terms isotherms, streamlines and Nu number for wider ranges of baffle positions and lengths, Rayleigh numbers, and by considering different nanofluid (NF) volume fractions. The average Nu number is enhanced in addition of the Cu nanoparticle to the base liquid and it is also found the liquid flow and heat transport can be successfully controlled via the appropriate selection of baffle location and length. Principally, the baffle length having 20% of annular width placed at 80% of the annular height has been found to produce higher thermal transport rates as compared to other choices of baffle lengths and positions.

Theoretical Analysis of Activation Energy Effect on Prandtl–Eyring Nanoliquid Flow Subject to Melting Condition

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ikram Ullah ◽  
Rashid Ali ◽  
Hamid Nawab ◽  
Abdussatar ◽  
Iftikhar Uddin ◽  
...  
Keyword(s):  
Differential Equation ◽  
Activation Energy ◽  
Convective Flow ◽  
Skin Friction Coefficient ◽  
System Of Equations ◽  
Energy Effect ◽  
Melting Condition ◽  
Ode System ◽  
Physical Importance ◽  
Controlling Variables

Abstract This study models the convective flow of Prandtl–Eyring nanomaterials driven by a stretched surface. The model incorporates the significant aspects of activation energy, Joule heating and chemical reaction. The thermal impulses of particles with melting condition is addressed. The system of equations is an ordinary differential equation (ODE) system and is tackled numerically by utilizing the Lobatto IIIA computational solver. The physical importance of flow controlling variables to the temperature, velocity and concentration is analyzed using graphical illustrations. The skin friction coefficient and Nusselt number are examined. The results of several scenarios, mesh-point utilization, the number of ODEs and boundary conditions evaluation are provided via tables.

Dispersion and Deposition of Particles in Rayleigh-Be´nard Turbulent Flows

2006 ◽  
Author(s):  
Paolo Oresta ◽  
Antonio Lippolis ◽  
Roberto Verzicco ◽  
Alfredo Soldati
Keyword(s):  
Aspect Ratio ◽  
Turbulent Flows ◽  
Convective Flow ◽  
Cylindrical Domain ◽  
Flow Topology ◽  
Vortical Structures ◽  
Dispersed Particles ◽  
Large Eddy ◽  
Prandtl Numbers ◽  
Rayleigh Numbers

In this paper, Direct Numerical Simulation (DNS) and Lagrangian Particle Tracking are used to investigate dispersion and deposition of particles swarms in convective flow confined in a cylindrical domain with aspect ratio (diameter over height) 0.5. The numerical simulations are carried out with Prandtl and Rayleigh numbers respectively equal to Pr = 0.7 and Ra = 2108. For these values of aspect ratio, Rayleigh and Prandtl numbers the flow is turbulent and time-dependent. In such flow, three sets of particles with Stokes numbers, based on the large eddy time scale, equal to Stf = 0.01, Stf = 0.005 and Stf = 0.001 are randomly dispersed. Particles distribution in turbulent convective flow is highly inhomogeneous and shows the clustering correlated with the vortical structures. The level of clustering is computed with the deviation of particles probability density function (PDF) from Poisson distribution. With this technique is available the size of the cluster but their geometry is unknown. The organisation along lines, planes and surfaces was investigated using the fractal dimension of the cluster. Finally, the flow topology is studied to relate the particles dispersion to coherent flow structures.

Transport Enhancement in Tunable Laser Cavity Sensor

2002 ◽  
Author(s):  
M. Sigurdson ◽  
C. Meinhart ◽  
D. Wang ◽  
X. Liu ◽  
J. J. Feng ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Optimization ◽  
Tunable Laser ◽  
Laser Cavity ◽  
Cfd Modeling ◽  
Physical Processes ◽  
Transport Enhancement ◽  
Computational Fluid Dynamics Cfd ◽  
Electrothermal Flow

Dielectrophoresis and Electrothermal Flow are two physical processes investigated for enhancing transport of antigen to a region of immobilized conjugate antibodies on an immunosensor surface. Computational fluid dynamics (CFD) modeling is employed to understand these phenomena in detail to aid in the design optimization of the device.

scholarly journals Inductive analysis of the deflection of a beam truss allowing kinematic variation

2018 ◽  
Vol 239 ◽  
pp. 01012
Author(s):  
Mikhail Kirsanov ◽  
Evgeny Komerzan ◽  
Olesya Sviridenko
Keyword(s):  
Optimal Design ◽  
External Load ◽  
Analytical Calculation ◽  
System Of Equations ◽  
Number Of Solutions ◽  
Recurrence Equations ◽  
General Terms ◽  
Cutting Out ◽  
Selection Of ◽  
Inductive Analysis

A scheme of a statically determinate planar truss is proposed and an analytical calculation of its deflection and displacement of the mobile support are obtained. The forces in the rods from the external load, uniformly distributed over the nodes of the lower or upper belt, are determined by the method of cutting out nodes using the computer mathematic system Maple. In the generalization of a number of solutions of trusses with a different number of panels to the general case, the general terms of the sequence of coefficients in the formulas are found from solutions of linear homogeneous recurrence equations. To compose and solve these equations, Maple operators were used. In the process of calculation it was revealed that for even numbers of panels in half the span, the determinant of the system of equations degenerates. This corresponds to the kinematic degeneracy of the structure. The corresponding scheme of possible speeds of the truss is given. The displacement was determined by the Maxwell-Mohr’s formula. The graphs of the obtained dependences have appreciable jumps, which in principle can be used in the selection of optimal design sizes.

scholarly journals A new regime of nanoscale thermal transport: Collective diffusion increases dissipation efficiency

2015 ◽  
Vol 112 (16) ◽  
pp. 4846-4851 ◽  
Author(s):  
Kathleen M. Hoogeboom-Pot ◽  
Jorge N. Hernandez-Charpak ◽  
Xiaokun Gu ◽  
Travis D. Frazer ◽  
Erik H. Anderson ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Free Path ◽  
Thermal Management ◽  
Thermal Transport ◽  
Heat Dissipation ◽  
Mean Free Path ◽  
Heat Sources ◽  
Nanoscale Systems ◽  
Nanoscale Thermal Transport ◽  
Thermal Therapies

Understanding thermal transport from nanoscale heat sources is important for a fundamental description of energy flow in materials, as well as for many technological applications including thermal management in nanoelectronics and optoelectronics, thermoelectric devices, nanoenhanced photovoltaics, and nanoparticle-mediated thermal therapies. Thermal transport at the nanoscale is fundamentally different from that at the macroscale and is determined by the distribution of carrier mean free paths and energy dispersion in a material, the length scales of the heat sources, and the distance over which heat is transported. Past work has shown that Fourier’s law for heat conduction dramatically overpredicts the rate of heat dissipation from heat sources with dimensions smaller than the mean free path of the dominant heat-carrying phonons. In this work, we uncover a new regime of nanoscale thermal transport that dominates when the separation between nanoscale heat sources is small compared with the dominant phonon mean free paths. Surprisingly, the interaction of phonons originating from neighboring heat sources enables more efficient diffusive-like heat dissipation, even from nanoscale heat sources much smaller than the dominant phonon mean free paths. This finding suggests that thermal management in nanoscale systems including integrated circuits might not be as challenging as previously projected. Finally, we demonstrate a unique capability to extract differential conductivity as a function of phonon mean free path in materials, allowing the first (to our knowledge) experimental validation of predictions from the recently developed first-principles calculations.

scholarly journals MODELING THE DYNAMICS OF PRESSURE AND TEMPERATURE IN THE RESERVOIR WITH HEAVY OIL WHEN HEATED

2017 ◽  
Vol 22 (1-2) ◽  
pp. 62-68
Author(s):  
V. Sh. Shagapov ◽  
Y. A. Yumagulova ◽  
A. A. Gizzatullina
Keyword(s):  
Mathematical Model ◽  
Heavy Oil ◽  
Horizontal Well ◽  
Oil Reservoir ◽  
System Of Equations ◽  
Thermal Waves ◽  
Reduced Viscosity ◽  
Symmetric Formulation ◽  
Heavy Oil Reservoir ◽  
Selection Of

In radially symmetric formulation is built and investigated mathematical model of the problem of heated heavy oil reservoir by horizontal well and the possibility of further operation of the well for the selection of oil with reduced viscosity. The resulting system of equations reveals the dynamics of the process, to evaluate the characteristics of the distance of penetration of filtration and thermal waves over the period.

Sign in / Sign up

Export Citation Format

Share Document