scholarly journals Simultaneous velocity profile and temperature profile measurements in microfluidics

2022 ◽  
pp. 102106
Author(s):  
Florian Bürkle ◽  
Jürgen Czarske ◽  
Lars Büttner
Keyword(s):  
Velocity Profile ◽  
Temperature Profile

scholarly journals Constraints on glacier flow from temperature-depth profiles in the ice. Application to EPICA Dome C.

2016 ◽  
Author(s):  
Ignacio Hermoso de Mendoza ◽  
Jean-Claude Mareschal ◽  
Hugo Beltrami
Keyword(s):  
Heat Flux ◽  
Velocity Profile ◽  
Boundary Conditions ◽  
Temperature Profile ◽  
East Antarctica ◽  
Surface Velocity ◽  
Function Parameter ◽  
Unknown Parameters ◽  
Conduction Model ◽  
Ice Flow

Abstract. A one-dimensional (1-D) ice flow and heat conduction model is used to calculate the temperature and heat flux profiles in the ice and to constrain the parameters characterizing the ice flow and the thermal boundary conditions at the Dome C drilling site in East Antarctica. We use the reconstructions of ice accumulation, glacier height and air surface temperature histories as boundary conditions to calculate the ice temperature profile. The temperature profile also depends on a set of poorly known parameters, the ice velocity profile and magnitude, basal heat flux, and air-ice surfaces temperature coupling. We use Monte Carlo methods to search the parameters' space of the model, compare the model output with the temperature data, and find probability distributions for the unknown parameters. We could not determine the sliding ratio because it has no effect on the thermal profile, but we could constrain the flux function parameter p that determines the velocity profile. We determined the basal heat flux qb = 49.0  ± 2.7 (2σ)m W m−2, almost equal to the apparent value. We found an ice surface velocity of vsur = 2.6 ± 1.9 (2σ)m y−1 and an air-ice temperature coupling of 0.8 ± 1.0(2σ)K. Our study confirms that the heat flux is low and does not destabilize the ice sheet in east Antarctica.

scholarly journals A numerical investigation of microwave ablation on porous liver tissue

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401773413 ◽  
Author(s):  
Pornthip Keangin ◽  
Phadungsak Rattanadecho
Keyword(s):  
Porous Media ◽  
Velocity Profile ◽  
Temperature Profile ◽  
Liver Tissue ◽  
Biological Tissues ◽  
Blood Velocity ◽  
Tumor Diameter ◽  
Coupled Models ◽  
Porous Media Model ◽  
The One

The understanding of heat transport in biological tissues is important for enhanced insight on the physiological mechanisms and thermoregulatory mechanisms. This article presents a numerical simulation of microwave (MW) ablation using a single-slot MW antenna on two layers of porous liver tissue. The two layers are of tumor and normal tissue. A porous media approach is proposed for mathematical model of MW ablation. Three coupled models which include transient momentum equations and a transient energy equation coupled with an electromagnetic wave propagation (EWP) equation are analyzed. This article focuses on the influences of the tumor diameter, tumor porosity, and input MW power on the specific absorption rate (SAR) profile, temperature profile, and blood velocity profile within the porous liver tissue. The results obtained from the calculation of porous media model are examined and compared with the one of bioheat model along with the experimental results from previous work. The results indicated that all parameters have a significant effect on the SAR profile, temperature profile, and blood velocity profile in the porous liver tissue. The advanced results in this research can be used in applications such as it provides guidance on the practical treatment and can be developed medically for therapeutic.

scholarly journals Aerodynamic Research on Straight Wall Annular Diffuser for Turbofan Augmentor

1985 ◽  
Author(s):  
Q. M. Xie ◽  
J. G. Gu
Keyword(s):  
Velocity Profile ◽  
Temperature Profile ◽  
Aerodynamic Performance ◽  
Recovery Coefficient ◽  
Momentum Ratio ◽  
Inlet Velocity ◽  
Straight Wall ◽  
Annular Diffuser ◽  
Aerodynamic Test ◽  
Pressure Recovery Coefficient

The effect of non-uniform inlet velocity and temperature profile on the aerodynamic performance of straight wall annular diffuser for turbofan augmentor has been investigated. The distribution of static pressure, stagnation pressure and temperature has been measured, thus pressure recovery coefficient, velocity profile and temperature profile at different axial station along the diffuser center line can be determined. The experimental results showed that the momentum ratio ρ¯eV¯e2/ρ¯iV¯i2 of two streams across the diffuser inlet flow splitter is the non-dimensional flow parameter controlling diffuser aerodynamic performance. Thus, it is possible to simulate turbofan augmentor annular diffuser perfomance by using low temperature air flow aerodynamic test under the condition that the diffusers are of similar geometry, have the same inlet velocity profile and maintain the momentum ratio constant. A correlation for the velocity distribution in the diffuser was also obtained.

Study of Molecular Dynamic Simulation of Poiseuille Flow in a Microchannel

2008 ◽  
Author(s):  
Chao Liu ◽  
Binwu Liu ◽  
Hualing Zhang
Keyword(s):  
Molecular Dynamics ◽  
Velocity Profile ◽  
Temperature Profile ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Large Jump ◽  
Wall Collision ◽  
Non Equilibrium Molecular Dynamics ◽  
Energy Equations ◽  
Good Agreement

A flow wall collision model between two parallel plane walls was established for argon fluid through a microchannel under the condition of action of periodical external force. Based on this model, two kinds of wall (hydrophilic and hydrophobic) were applied on the flow simulations from non-equilibrium molecular dynamics (NEMD). There are 864 fluid particles and wall particles separately in the simulated system. The non-dimension height of microchannel is 9.667. The velocity profile and temperature profile of argon fluid in hydrophilic microchannel predicted by molecular dynamics simulation are in good agreement with the analytical solution based on the Navier–Stokes and energy equations. The velocity profile and the temperature profile experience a large jump in the layers close to the hydrophobic wall.

Buoyancy Effects in Forced Laminar Convection Flow Over a Horizontal Flat Plate

1961 ◽  
Vol 83 (4) ◽  
pp. 479-482 ◽  
Author(s):  
Yasuo Mori
Keyword(s):  
Nusselt Number ◽  
Power Series ◽  
Velocity Profile ◽  
Flat Plate ◽  
Temperature Profile ◽  
Forced Convection ◽  
Convection Flow ◽  
Buoyancy Forces ◽  
Forced Convection Flow ◽  
Laminar Convection

Effects of buoyancy forces in a forced laminar convection flow over a horizontal flat plate is analyzed. It is shown that the solutions may be expanded into power series in Grx/Rex2.5 whose first terms express the solution for the purely forced convection flow. A numerical example is given to show the effects of Grashof number on the velocity profile, the temperature profile, and the Nusselt number.

A Numerical Method for Calculating Fully Developed Laminar Velocity Profiles From Temperature Profiles

1970 ◽  
Vol 92 (2) ◽  
pp. 245-251 ◽  
Author(s):  
L. O. Billig ◽  
K. R. Galle
Keyword(s):  
Velocity Profile ◽  
Computer Program ◽  
Numerical Method ◽  
Temperature Profile ◽  
Velocity Profiles ◽  
Temperature Profiles ◽  
Reasonable Accuracy ◽  
Experimental Errors ◽  
Calculated Velocity

It is noted that the velocity profile has a significant effect on the temperature profile that develops in a fluid flowing through a tube. A numerical method for retrieving the velocity profile from a temperature profile is given and the computer program written to implement the method is described. The method retrieved velocity profiles of reasonable accuracy from temperature profiles calculated from the Graetz solution and by Kays’ numerical method. The results of a study to estimate the effects of possible experimental errors from several possible sources on the calculated velocity profiles are included.

Power Law Velocity and Temperature Profiles in a Fully Developed Turbulent Channel Flow

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Abu Seena ◽  
Noor Afzal
Keyword(s):  
Heat Transfer ◽  
Velocity Profile ◽  
Temperature Profile ◽  
Channel Flow ◽  
Power Law ◽  
Turbulent Channel Flow ◽  
Temperature Profiles ◽  
Fully Developed Turbulent Flow ◽  
Friction Temperature ◽  
Log Law

Abstract The power law temperature distribution in a fully developed turbulent channel flow for large Peclet numbers has been proposed in the present work. The analysis of the power law velocity profile in a fully developed mean turbulent channel flow would be used for carrying out the analysis of the power law temperature profile. The Reynolds mean thermal energy equation in a fully developed mean turbulent channel flow has been analyzed. The mean turbulent thermal flow is divided in the inner and outer thermal layers that have been matched by Izakson–Millikan–Kolmogorov hypothesis to get the power law temperature profiles and the power law heat transfer law in the overlap region, in addition to traditional log laws for temperature profiles and heat transfer. It has been shown that the envelope of the heat transfer power law gives the heat transfer log law. Further, it is shown that the temperature power law index and prefactor are functions of the friction Peclet number, as well as function of an alternate variable, the nondimensional friction temperature. It is shown that for large Peclet numbers the power law temperature profile is equivalent to the log law temperature profile. The direct numerical simulation velocity profile data of fully developed turbulent flow provide good support for the power law temperature profile theory.

Effects of thermal radiation and electromagnetohydrodynamics on viscous nanofluid through a Riga plate

2016 ◽  
Vol 12 (4) ◽  
pp. 605-618 ◽  
Author(s):  
Muhammad Mubashir Bhatti ◽  
Tehseen Abbas ◽  
M.M. Rashidi
Keyword(s):  
Velocity Profile ◽  
Thermal Radiation ◽  
Temperature Profile ◽  
Radiation Effects ◽  
Constant Density ◽  
Nanoparticle Concentration ◽  
Content Type ◽  
Riga Plate ◽  
Concentration Equation ◽  
The Impact

Purpose The purpose of this paper is to analyze theoretically the effects of thermal radiation with electrohydrodynamics through a Riga plate. An incompressible and irrotational fluid with constant density is taken into account. The governing flow problem is modeled with the help of linear momentum, thermal energy equation and nanoparticle concentration equation. Design/methodology/approach Numerical integration is used with the help of the shooting technique to examine the novel features of the velocity profile, temperature profile and nanoparticle concentration profile. The impact of all the emerging parameters is sketched with the help of graphs. The numerical values of local Nusselt number and Sherwood number are also presented. Findings The no-slip condition is considered for the present study. The effects of electromagnetohydrodynamics enhance the velocity profile while thermal radiation effects tend to raise the temperature profile. The present study depicts many interesting behaviors that warrant further study on Riga plates with different non-Newtonian fluid models. A comparison is also presented with the existing published results which confirms the validity of the presented methodology. Originality/value The results of this paper are new and original.

Development of Velocity and Temperature of the Flow behind a Moving Shock Wave in a duct

1976 ◽  
Vol 190 (1) ◽  
pp. 437-446 ◽  
Author(s):  
B. E. L. Deckker ◽  
M. E. Weekes
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Velocity Profile ◽  
Temperature Profile ◽  
Wave Front ◽  
Rectangular Duct ◽  
Hot Wire ◽  
Atmospheric Air ◽  
Steady Velocity ◽  
Boundary Layer Edge

SYNOPSIS Development of the velocity and temperature of the flow behind a shock wave propagating in atmospheric air in a smooth rectangular duct has been followed by hot wire anemometry. Averaged data were analyzed iteratively to yield the velocity and temperature at several points. Property distributions close to the wave front are non-uniform. Far from the front, the steady velocity profile is approximately the same as for flow in a rectangular duct. The temperature profile develops in a similar manner to the velocity but it is difficult to define the boundary layer edge because the temperature decreases with time.

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