scholarly journals Implications of Multiple Numerical Aspects for Carreau Nanofluids With Heat Generation/absorption via Nonuniform Channels

2022 ◽  
Author(s):  
Hashim Hashim ◽  
Sohail Rehman
Keyword(s):  
Heat Dissipation ◽  
Concentration Field ◽  
Computer Software ◽  
Variable Magnetic Field ◽  
Physical Parameters ◽  
Heat Absorption ◽  
Convergent Channel ◽  
Carreau Nanofluid ◽  
Generation Parameter ◽  
Shooting Algorithm

Abstract Nanomaterials are unique work fluids with preeminent thermal performance for improving heat dissipation. We present theoretical and mathematical insights into nanofluid heat transfer and flow dynamics in nonuniform channels utilizing a non-Newtonian fluid. Therefore, the impacts of heat absorption/generation and Joule heating in a magneto hydrodynamic flow of a Carreau nanofluid into a convergent channel with viscous dissipation are addressed in this mathematical approach. Brownian and thermophoresis diffusion are considered to investigate the behavior of temperature and concentration. The magnetic effects on the flow performance are measured. The leading nonlinear equations are solved numerically using the BVP4c solver and RK-4 (Runge–Kutta) along with the shooting algorithm using the computer software MATLAB. The obtained dual solutions are presented graphically. The consequences of the variable magnetic field, heat absorption/generation and numerous physical parameters on the temperature and concentration field are surveyed. The outcomes show that increasing the rates of the heat absorption/generation parameter and Eckert number enhances the thickness of the thermal profile of the convergent channels, while increasing the value of the Prandtl number expands the thickness of the momentum boundary layer of the convergent channels. The key findings related to the study models are presented and discussed. An assessment of solutions achieved in this article is made with existing data in the literature.

scholarly journals Research computer numerical simulation on heat dissipation model of submarine data centre based on TOPSIS model

2021 ◽  
Vol 2083 (4) ◽  
pp. 042062
Author(s):  
Rui Qin ◽  
Man Zhang ◽  
Lijie Chen ◽  
Xiao Liu ◽  
Zhengtao Lei ◽  
...  
Keyword(s):  
Data Centers ◽  
Heat Dissipation ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Model Material ◽  
Physical Parameters ◽  
Deep Seawater ◽  
Dissipation Model ◽  
Computer Numerical Simulation ◽  
Optimal Evaluation

Abstract Due to the huge energy consumption of land-based data centers, it is necessary to establish undersea data centers as soon as possible in order to alleviate the problem of resource tension. In this paper, the uniformity of containers is assumed. Through force analysis, it is found that the stress of containers is uniformly distributed, so only the external stress should be considered. Hypothesis submarine data center in the 50 m deep seawater, calculate the container need to withstand stress is 76.417403 Mpa, common material in engineering field, then physical parameters of material to deal with the dimensional and normalization, and establishes a comprehensive evaluation model material, the Topsis method is adopted to solve, to solve the optimal evaluation of the results can be divided into: 7-4 PH Stainless Stee 0.7450 points, so choose it as IU server container material.

Effect of heating rate on evaporative heat loss in the microwave-exposed mouse

1982 ◽  
Vol 53 (2) ◽  
pp. 316-323 ◽  
Author(s):  
C. J. Gordon
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Heat Dissipation ◽  
Dew Point ◽  
Whole Body ◽  
Evaporative Heat Loss ◽  
Heat Absorption ◽  
Deep Body Temperature ◽  
The Difference ◽  
Body Heat

Male CBA/J mice were administered heat loads of 0–28 J X g-1 at specific absorption rates (SARs) of either 47 or 93 W X kg-1 by exposure to 2,450-MHz microwave radiation at an ambient temperature of 30 degrees C while evaporative heat loss (EHL) was continuously monitored with dew-point hygrometry. At an SAR of 47 W X kg-1 a threshold heat load of 10.5 J X g-1 had to be exceeded before EHL increased. An approximate doubling of SAR to 93 W X kg-1 reduced the threshold to 5.2 J X g-1. Above threshold the slopes of the regression lines were 1.15 and 0.929 for the low- and high-SAR groups, respectively. Thus the difference in threshold and not slope attributes to the significant increase in EHL when mice are exposed at a high SAR (P less than 0.02). In separate experiments a SAR of 47 W X kg-1 raised the deep body temperature of anesthetized mice at a rate of 0.026 degrees C X s-1, whereas 93 W X kg-1 raised temperature at 0.049 degrees C X s-1. Hence the sensitivity of the EHL mode of heat dissipation is directly proportional to the rate of heat absorption and to the rate of rise in body temperature. These data contradict the notion that mammals have control over whole-body heat exchange only (i.e., thermoregulation) but instead indicate that the EHL system is highly responsive to the rate of heat absorption (i.e., temperature regulation).

scholarly journals A new method to calculate the friction coefficient of ball screws based on the thermal equilibrium

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882073
Author(s):  
Lu-Chao Zhang ◽  
Li Zu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Mechanical Efficiency ◽  
New Method ◽  
Measuring System ◽  
Ball Screw ◽  
Heat Absorption ◽  
Screw Mechanism

Based on the theory of thermal transmission, this article provides a new method to acquire the friction coefficient in ball screw mechanism. While the screw is in thermal equilibrium, the heat absorption is equal to the heat dissipation. The heat absorption is able to be achieved by calculating the heat energy due to the friction at the contact area and the heat dissipation can be calculated by the law of thermodynamics. When the temperature rise is determined, the heat dissipation can be obtained and the friction coefficient in ball screw mechanism can be calculated further. In order to confirm the validity of this method, a measuring system is constructed to obtain the temperature rise of ball screws. The experimental results show that the temperature rise has the same tendency with the theoretical values depending on this model. Therefore, it can be exploited to predict the temperature rise of ball screws in the rated life cycle when the ball screw is under the condition of thermal equilibrium. Furthermore, this model can be used to evaluate the mechanical efficiency, which is an important parameter for the performance of the ball screw.

scholarly journals New Orbits for Enceladus and Dione Based on the Photographic Observations

1978 ◽  
Vol 41 ◽  
pp. 239-239
Author(s):  
W.H. Jefferys ◽  
J.D. Mulholland ◽  
L.M. Ries
Keyword(s):  
Gravitational Field ◽  
Computer Software ◽  
Physical Parameters ◽  
Theoretical Studies ◽  
Orbital Theory ◽  
Orbital Parameters ◽  
Outer Planets ◽  
Computer Software System ◽  
Near Future ◽  
Orbit Problem

AbstractA program is underway at the McDonald Observatory to extend the series of photographic observations of the satellites of the outer planets (Abbot, Mulholland and Shelus, A.J. 80, 1975), and concurrent theoretical studies have led to a new orbital theory for the resonant pair of satellites, Enceladus and Dione (Jefferys and Ries, A.J. 80, 1975). The construction of the new theory, using the computer software system TRIGMAN, has provided Fortran subroutines for the computation of the planetocentric coordinates of the two satellites, as well as partial derivatives for the orbit elements and certain other physical parameters of the orbit problem, including some of the harmonics of the gravitational field of Saturn. The available photographic observations for these two objects are currently being discussed with the new theory, and improved values of the orbital parameters are expected in the near future.

Series solution for flow of a second-grade fluid in a divergent–convergent channel

2010 ◽  
Vol 88 (12) ◽  
pp. 911-917 ◽  
Author(s):  
T. Hayat ◽  
M. Nawaz ◽  
S. Asghar ◽  
Awatif A. Hendi
Keyword(s):  
Series Solution ◽  
Problem Formulation ◽  
Skin Friction Coefficient ◽  
Second Grade ◽  
Physical Parameters ◽  
Analysis Method ◽  
Second Grade Fluid ◽  
Convergent Channel ◽  
Homotopy Analysis ◽  
Grade Fluid

This study explores the flow of a second-grade fluid in divergent–convergent channel. The problem formulation is first developed, and then the corresponding nonlinear problem is solved by homotopy analysis method (HAM). The effects of different physical parameters on the velocity profile are shown. The numerical values of the skin friction coefficient for different values of parameters are tabulated.

A Novel Structural Design of Heat-Dissipation Method for High Brightness LED Lighting with Thermoelectric Chip Module

2014 ◽  
Vol 1051 ◽  
pp. 823-827
Author(s):  
Ching Wu Wang ◽  
Ti Chun Yeh ◽  
Kai Chun Lin ◽  
Kuan Hsun Chen ◽  
Wei Chih Wang ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Layered Structure ◽  
Structural Design ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Thermoelectric Module ◽  
Heat Absorption ◽  
High Brightness ◽  
Led Lighting ◽  
Novel Structure

In various traditional technologies of solving the heat-dissipation problem for LED, all of these methods exhaust the waste heat into the environment and cause the more serious greenhouse effect. In this article, we present a new heat-dissipation method for high brightness 10W LED bulb using a novel structure of thermoelectric chip module. Evidence illustrates that graphite performs both the best heat-absorption material as well as the superior heat-dissipation material for LED thermoelectric chip module. Besides, the double-layered structure with graphite as heat-conduction material of LED thermoelectric module could create the most temperature-difference and thus conduct the highest output power. It implies that double-layered structure of LED thermoelectric chip module with graphite as heat-conduction material is the optimal structure for heat-dissipation of 10W LED bulb.

Heat dissipation by blood circulation and airway tissue heat absorption in a canine model of inhalational thermal injury

Burns ◽  
2016 ◽  
Vol 42 (3) ◽  
pp. 548-555 ◽  
Author(s):  
Jiangbo Wan ◽  
Guoan Zhang ◽  
Yuxuan Qiu ◽  
Chunquan Wen ◽  
Tairan Fu
Keyword(s):  
Blood Circulation ◽  
Heat Dissipation ◽  
Thermal Injury ◽  
Canine Model ◽  
Heat Absorption

scholarly journals Variable thickness flow over a rotating disk under the influence of variable magnetic field: An application to parametric continuation method

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093638 ◽  
Author(s):  
Muhammad Shuaib ◽  
Rehan Ali Shah ◽  
Muhammad Bilal
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Variable Thickness ◽  
Numerical Scheme ◽  
Continuation Method ◽  
Finite Difference Methods ◽  
Rotating Disk ◽  
Variable Magnetic Field ◽  
Physical Parameters ◽  
Parametric Continuation

The present work explores the behavior of three-dimensional incompressible viscous fluid flow and heat transfer over the surface of a non-flat stretchable rotating disk. A variable thickness fluid is subjected under the influence of an external variable magnetic field and heat transfer. Navier–Stokes equation is coupled with Maxwell equations to examine the hydrothermal properties of fluid. The basic governing equations of motion are diminished to a system of nonlinear ordinary differential equations using appropriate similarity framework, which are further treated with numerical scheme known as parametric continuation method. The parametric continuation method has combined interesting characteristics of both shooting and implicit finite difference methods. For validity of the present numerical scheme, a comparison with the published work is performed and it is found that the results are in excellent agreement with each other. Numerical and graphical results for the velocity, temperature, and magnetic strength profiles as well as skin fractions and Nusselt number are presented and discussed in detail for various physical parameters. The heat transfer process is reduced with positive increment of no-flatness parameter [Formula: see text], while Prandtl number increases the heat transfer rate at the surface of the disk.

Dissolution or growth of soluble spherical oscillating bubbles

1994 ◽  
Vol 277 ◽  
pp. 381-407 ◽  
Author(s):  
Marios M. Fyrillas ◽  
Andrew J. Szeri
Keyword(s):  
Multiple Scales ◽  
Large Body ◽  
Concentration Field ◽  
Physical Parameters ◽  
Dissolved Gas ◽  
Analytical Treatment ◽  
Oscillatory Problem ◽  
Oscillating Bubbles ◽  
New Formulation ◽  
Bubble Oscillations

A new theoretical formulation is presented for mass transport across the dynamic interface associated with a spherical bubble undergoing volume oscillations. As a consequence of the changing internal pressure of the bubble that accompanies volume oscillations, the concentration of the dissolved gas in the liquid at the interface undergoes large-amplitude oscillations. The convection-diffusion equations governing transport of dissolved gas in the liquid are written in Lagrangian coordinates to account for the moving domain. The Henry's law boundary condition is split into a constant and an oscillating part, yielding the smooth and the oscillatory problems respectively. The solution of the oscillatory problem is valid everywhere in the liquid but differs from zero only in a thin layer of the liquid in the neighbourhood of the bubble surface. The solution to the smooth problem is also valid everywhere in the liquid; it evolves via convection-enhanced diffusion on a slow timescale controlled by the Péclet number, assumed to be large. Both the oscillatory and smooth problems are treated by singular perturbation methods: the oscillatory problem by boundary-layer analysis, and the smooth problem by the method of multiple scales in time. Using this new formulation, expressions are developed for the concentration field outside a bubble undergoing arbitrary nonlinear periodic volume oscillations. In addition, the rate of growth or dissolution of the bubble is determined and compared with available experimental results. Finally, a new technique is described for computing periodically driven nonlinear bubble oscillations that depend on one or more physical parameters. This work extends a large body of previous work on rectified diffusion that has been restricted to the assumptions of infinitesimal bubble oscillations or of threshold conditions, or both. The new formulation represents the first self-consistent, analytical treatment of the depletion layer that accompanies nonlinear oscillating bubbles that grow via rectified diffusion.

Activation energy and binary chemical reaction effect in nonlinear thermal radiative stagnation point flow of Walter-B nanofluid: Numerical computations

2020 ◽  
Vol 34 (13) ◽  
pp. 2050132 ◽  
Author(s):  
M. Ijaz Khan ◽  
Faris Alzahrani
Keyword(s):  
Activation Energy ◽  
Stagnation Point ◽  
Chemical Reaction ◽  
Heat Generation ◽  
Biot Number ◽  
Concentration Field ◽  
Weissenberg Number ◽  
Stagnation Point Flow ◽  
Eckert Number ◽  
Generation Parameter

This paper examines nonlinear thermal radiative stagnation point flow of Walter-B nanofluid. The characteristics of nanofluid are explored using Brownian motion and thermophoresis effects. In the presence of uniform magnetic field, fluid is conducting electrically. Furthermore, phenomena of mass and heat transfer are studied by implementing the effects of chemical reaction, Joule heating and activation energy. Outcomes of distinct variables such as induced magnetic parameter, Eckert number, thermal radiation parameter, Weissenberg number, ratio of rate constant, heat capacity ratio, thermal Biot number, solutal Biot number, Prandtl number, heat generation parameter, Schmidt number on concentration, temperature and velocity distributions are explored. The numerical method is implemented to solve the governing flow expression. Further, Sherwood number, Nusselt number and skin friction coefficient are analyzed and discussed in tables. Weissenberg number have opposite behavior on velocity field while it increases for larger values of mixed convection parameter. Temperature of the fluid rises for higher values of thermal Biot number, thermophoresis diffusion coefficient, heat generation parameter and Eckert number Activation energy parameter and Weissenberg number have direct relation with concentration field.

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