Use of Physical Quantities, Units, Mathematics, and Nomenclature in Heat Transfer Publications

1988 ◽  
Vol 9 (4) ◽  
pp. 73-88
Author(s):  
YON R. MAYHEW
2020 ◽  
Vol 41 (11) ◽  
pp. 1707-1722
Author(s):  
M. H. A. Kamal ◽  
N. A. Rawi ◽  
A. Ali ◽  
S. Shafie

Abstract The unsteady double diffusion of the boundary layer with the nanofluid flow near a three-dimensional (3D) stagnation point body is studied under a microgravity environment. The effects of g-jitter and thermal radiation exist under the microgravity environment, where there is a gravitational field with fluctuations. The flow problem is mathematically formulated into a system of equations derived from the physical laws and principles under the no-slip boundary condition. With the semi-similar transformation technique, the dimensional system of equations is reduced into a dimensionless system of equations, where the dependent variables of the problem are lessened. A numerical solution for the flow problem derived from the system of dimensionless partial differential equations is obtained with the Keller box method, which is an implicit finite difference approach. The effects studied are analyzed in terms of the physical quantities of principle interest with the fluid behavior characteristics, the heat transfer properties, and the concentration distributions. The results show that the value of the curvature ratio parameter represents the geometrical shape of the boundary body, where the stagnation point is located. The increased modulation amplitude parameter produces a fluctuating behavior on all physical quantities studied, where the fluctuating range becomes smaller when the oscillation frequency increases. Moreover, the addition of Cu nanoparticles enhances the thermal conductivity of the heat flux, and the thermal radiation could increase the heat transfer properties.


2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
M. B. Akgül ◽  
M. Pakdemirli

The effect of different types of nanoparticles on the heat transfer from a continuously moving stretching surface in a concurrent, parallel free stream has been studied. The stretching surface is assumed to have power-law velocity and temperature. The governing equations are converted into a dimensionless system of equations using nonsimilarity variables. Resulting equations are solved numerically for various values of flow parameters. The effect of physical quantities on the temperature profiles is discussed in detail.


2014 ◽  
Vol 18 (2) ◽  
pp. 357-364 ◽  
Author(s):  
Tasawar Hayat ◽  
Majid Hussain ◽  
Sohail Nadeem ◽  
Saleem Obaidat

An analysis has been carried out for the hydromagnetic flow and heat transfer over a horizontal surface located in an externally squeezed free stream. Mathematical formulation is developed by using constitutive equations of a second grade fluid. The resulting problems have been solved by a homotopy analysis method (HAM). In addition the skin friction coefficient and Nusselt number are tabulated. The physical quantities of interest are analyzed for various emerging parameters.


2019 ◽  
Vol 1 (2) ◽  
pp. 58-61
Author(s):  
MOHAMAD HIDAYAD BIN AHMAD KAMAL ◽  
NORAIHAN AFIQAH RAWI ◽  
ANATI AHMAD ALI ◽  
SHARIDAN AHMAD SHAFIE

The fundamental research near a boundary layer nanofluid flow at a stagnation point region with thermal radiation effect is conducted under microgravity environment. The mathematical formulation is modified from physical law to represent the physical characteristic of the flow and the system of the equation are solved numerically using Keller box method. The flow is analyzed in terms of physical quantities of principal interest such as skin friction and Nusset number. Parameters consider in this flow such as curvature ratio, amplitude of modulation, frequency of oscillation, nanoparticles volume friction and thermal radiation is analyzed numerically and presented graphically. From the analysis, g-jitter effect will produce a fluctuating result to the skin frictions and Nusset number indicate the singularity solution in the flow. The existing of nanoparticles and thermal radiation is found to increase the rate of heat transfer of the flow.


2015 ◽  
Vol 08 (06) ◽  
pp. 1550073 ◽  
Author(s):  
T. Hayat ◽  
Maimona Rafiq ◽  
B. Ahmad ◽  
H. Yasmin

Mathematical model is developed for peristaltic flow of viscous fluid through a compliant wall channel subject to melting heat transfer. Fluid is incompressible and magnetohydrodynamic. Analysis has been performed in the presence of Joule heating and thermal radiation. Solutions for small wave number are obtained. Physical quantities of interest are examined for various parameters of interest.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Barbara Bosio ◽  
Dario Bove ◽  
Lorenzo Guidetti ◽  
Leopoldo Avalle ◽  
Elisabetta Arato

Cryosurgery is a rapidly developing discipline, alternative to conventional surgical techniques, used to destroy cancer cells by the action of low temperatures. Currently, the refrigeration is obtained via the adiabatic expansion of gases in probes used for surgeries, with the need of inherently dangerous pressurized vessels. The proposed innovative prototypal apparatus aims to reach the cryosurgical temperatures exploiting a closed-loop refrigeration system, avoiding the hazardous presence of pressurized vessels in the operating room. This study preliminarily examines the technical feasibility of the cryoablation with this machine focusing the attention on the cryoprobe design. Cryoprobe geometry and materials are assessed and the related heat transfer taking place during the cryoablation process is simulated with the aid of the computational fluid dynamics software ANSYS®Fluent. Parametric analyses are carried out varying the length of the collecting tubes and the inlet velocity of the cold carrier fluid in the cryoprobe. The values obtained for physical quantities such as the temperature reached in the treated tissue, the width of the obtained cold front, and the maximum pressure required for the cold carrier fluid are calculated and discussed in order to prove the effectiveness of the experimental apparatus and develop the machine further.


Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 488 ◽  
Author(s):  
Nawaf Hamadneh ◽  
Waqar Khan ◽  
Ilyas Khan ◽  
Ali Alsagri

In this study, pressure-driven flow in the slip regime is investigated in rectangular microducts. In this regime, the Knudsen number lies between 0.001 and 0.1. The duct aspect ratio is taken as 0 ≤ ε ≤ 1 . Rarefaction effects are introduced through the boundary conditions. The dimensionless governing equations are solved numerically using MAPLE and MATLAB is used for artificial neural network modeling. Using a MAPLE numerical solution, the shear stress and heat transfer rate are obtained. The numerical solution can be validated for the special cases when there is no slip (continuum flow), ε = 0 (parallel plates) and ε = 1 (square microducts). An artificial neural network is used to develop separate models for the shear stress and heat transfer rate. Both physical quantities are optimized using a particle swarm optimization algorithm. Using these results, the optimum values of both physical quantities are obtained in the slip regime. It is shown that the optimal values ensue for the square microducts at the beginning of the slip regime.


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