Do We Really Need “Entransy”? A Critical Assessment of a New Quantity in Heat Transfer Analysis

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
H. Herwig
Keyword(s):  
Heat Transfer ◽  
Classical Theory ◽  
Critical Assessment ◽  
Heat Transfer Analysis ◽  
Classical Approach ◽  
The Past ◽  
Transfer Problems

Recently, a group of scientists introduced a new quantity for the analysis of heat transfer problems. They called it entransy since according to their understanding it is both, an indication of the nature of energy as well as that of the heat transfer ability. This concept is critically assessed on the background of two questions: Is entransy as an extension of the well established theory of heat transfer consistent with this classical approach? And: Is there a real need for the extension of the classical theory by introducing entransy as a quantity that was missing in the past?

Conjugate Heat Transfer Analysis of Internally Cooled Configurations

2001 ◽  
Author(s):  
David L. Rigby ◽  
Jan Lepicovsky
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Energy Equation ◽  
Reynolds Numbers ◽  
Heat Transfer Analysis ◽  
Navier Stokes ◽  
The Past ◽  
Flow And Heat Transfer ◽  
Internally Cooled ◽  
Solid Region

This paper describes the addition of conjugate capability to an existing Navier-Stokes code. Also, results are presented for an internally cooled configuration. The code is currently referred to as the Glenn-HT code, because of its origin at the NASA Glenn Research center and its proven ability to predict flow and Heat Transfer. In the past, the code had been called traf3d.mb. The addition of the conjugate capability to the code was accomplished with a minimum amount of changes to the code, with the understanding that if more advanced techniques were required they could be added at a later date. In the solid region, the density is constant and the velocities are of course zero which leaves only a simplified form of the energy equation to be solved. This simplified energy equation is solved using the same method as in the gas regions with only minor changes to the numerical parameters. At the interface between the gas and solid the wall temperature is set so as to produce the same heat flux in each region. Results are presented for a pipe flow to validate the implementation. Numerical and experimental results are then presented for flow over a flat plate that is cooled internally. Flat plate Reynolds numbers in the range 180,000 to 950,000, and coolant channel Reynolds numbers in the range 30,000 to 60,000 are presented.

Discussion: “Entransy is Now Clear”

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
M. M. Awad
Keyword(s):  
Heat Transfer ◽  
Critical Assessment ◽  
Heat Transfer Analysis

The purpose of this discussion is to place in perspective the concept of entransy, in view of the critiques published by Grazzini et al. (2013, “Entropy Versus Entransy,” J. Non-Equilib. Thermodyn., 38, pp. 259–271), Herwig (2014, “Do We Really Need ‘Entransy’? A Critical Assessment of a New Quantity in Heat Transfer Analysis,” ASME J. Heat Trans., 136(4), 045501), and Bejan 2014, ““Entransy,” and Its Lack of Content in Physics,” ASME J. Heat Trans., 136(5), 055501), and especially the response just published by Guo et al. (2014, “A Response to Do We Really Need ‘Entransy’?” ASME J. Heat Trans., 136(4), 046001). The conclusion is that entransy is improper and not needed, and that Guo et al.'s own response actually confirms this conclusion.

scholarly journals Heat Transfer Analysis for FGMs Using SPH-CSPM

2010 ◽  
Vol 452-453 ◽  
pp. 685-688 ◽  
Author(s):  
Gui Ming Rong ◽  
Hiroyuki Kisu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Method ◽  
Heat Transfer Analysis ◽  
Graded Materials ◽  
Various Boundary Conditions ◽  
Particle Hydrodynamics ◽  
Spatial Coordinates ◽  
Smoothed Particle ◽  
Transfer Problems

The solution of heat transfer problems for functional graded materials (FGMs) by smoothed particle hydrodynamics, in which the thermal conductivity is a function of the spatial coordinates and the temperature, is discussed for both steady and non-steady problems under various boundary conditions. The boundary is treated using the corrective smoothed particle method to heighten the accuracy. Several calculations are performed to test the validity of the formulation. As an example of practical application, the problem of FGM cylindrical plates subjected to thermal shock is calculated, in which the thermal conductivity is temperature dependent and the heat transfer coefficient is varied in radial direction.

scholarly journals An enhanced nodal gradient finite element for non-linear heat transfer analysis

2019 ◽  
Author(s):  
Minh Ngoc Nguyen ◽  
Tich Thien Truong ◽  
Tinh Quoc Bui
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Heat Transfer Analysis ◽  
Order Continuity ◽  
Linear Heat ◽  
Non Linear ◽  
Interpolation Procedure ◽  
Transfer Problems

The present work is devoted to the analysis of non-linear heat transfer problems using the recent development of consective-interpolation procedure. Approximation of temperature is enhanced by taking into account both the nodal values and their averaged nodal gradients, which results in an improved finite element model. The novel formulation possesses many desirable properties including higher accuracy and higher-order continuity, without any change of the total number of degrees of freedom. The non-linear heat transfer problems equation is linearized and iteratively solved by the Newton-Raphson scheme. To show the accuracy and efficiency of the proposed method, several numerical examples are hence considered and analyzed.

Universal Gray Finite Elements for Heat Transfer Analysis in the Presence of Uncertainties

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Ashkan Nejadpak ◽  
Singiresu S. Rao
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Number Theory ◽  
Interval Analysis ◽  
Thermal Power ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Number Representation ◽  
Computationally Intensive ◽  
Transfer Problems

Abstract A new finite element method is presented for the analysis of uncertain heat transfer problems using universal gray number theory. The universal gray number representation involves normalization of the uncertain parameters based on their lower and upper bound values with its own distinctive rules of arithmetic operations which makes this method distinctive from conventional interval analysis approaches. This work introduces the concept of fuzzy finite element-based heat transfer analysis using universal gray number theory, that compared to the interval-based fuzzy analysis, would yield significantly improved and more accurate results. Heat transfer problems, including a one-dimensional tapered fin, a two-dimensional hollow rectangle representing a thin slice of a chimney of a thermal power plant, and a three-dimensional (axisymmetric) solid body with different boundary conditions, were considered for the uncertainty analysis. It is shown that, in each case, the interval values of the response parameters given by the universal gray number theory are consistent with the ranges of the input parameters, compared to those given by the interval analysis. It is also revealed that universal gray number theory is more inclusive and less computationally intensive compared to the interval analysis.

scholarly journals Development of Pulsating Twin Jets Mechanism for Mixing Flow Heat Transfer Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Ali Ahmed Gitan ◽  
Rozli Zulkifli ◽  
Shahrir Abdullah ◽  
Kamaruzzaman Sopian
Keyword(s):  
Heat Transfer ◽  
Velocity Profile ◽  
Heat Transfer Analysis ◽  
Pulsation Frequency ◽  
Pulse Profile ◽  
Pulsed Jet ◽  
Impingement Heat Transfer ◽  
Twin Jets ◽  
Flow Heat ◽  
Transfer Problems

Pulsating twin jets mechanism (PTJM) was developed in the present work to study the effect of pulsating twin jets mixing region on the enhancement of heat transfer. Controllable characteristics twin pulsed jets were the main objective of our design. The variable nozzle-nozzle distance was considered to study the effect of two jets interaction at the mixing region. Also, the phase change between the frequencies of twin jets was taken into account to develop PTJM. All of these factors in addition to the ability of producing high velocity pulsed jet led to more appropriate design for a comprehensive study of multijet impingement heat transfer problems. The performance of PTJM was verified by measuring the pulse profile at frequency of 20 Hz, where equal velocity peak of around 64 m/s for both jets was obtained. Moreover, the jet velocity profile at different pulsation frequencies was tested to verify system performance, so the results revealed reasonable velocity profile configuration. Furthermore, the effect of pulsation frequency on surface temperature of flat hot plate in the midpoint between twin jets was studied experimentally. Noticeable enhancement in heat transfer was obtained with the increasing of pulsation frequency.

scholarly journals A consecutive-interpolation finite element method for heat transfer analysis

2015 ◽  
Vol 18 (2) ◽  
pp. 21-28
Author(s):  
Minh Ngoc Nguyen ◽  
Nha Thanh Nguyen ◽  
Tinh Quoc Bui ◽  
Thien Tich Truong
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Interpolation Condition ◽  
Numerical Examples ◽  
Quadrilateral Finite Element ◽  
Transfer Problems

A consecutive-interpolation 4-node quadrilateral finite element (CQ4) is further extended to solve twodimensional heat transfer problems, taking the average nodal gradients as interpolation condition, resulting in highorder continuity solution without smoothing operation and without increasing the number of degrees of freedom. The implementation is straightforward and can be easily integrated into any existing FEM code. Several numerical examples are investigated to verify the accuracy and efficiency of the proposed formulation in two-dimensional heat transfer analysis.

Heat Transfer Simulation Using PSpice

2003 ◽  
Author(s):  
Shuhui Li ◽  
Rajab Challoo ◽  
Robert A. McLauchlan
Keyword(s):  
Heat Transfer ◽  
Energy Flow ◽  
Large Scale ◽  
Network Models ◽  
Heat Transfer Analysis ◽  
Electric Circuits ◽  
Transfer Equations ◽  
Heat Transfer Simulation ◽  
Almost All ◽  
Transfer Problems

Heat transfer considerations are important in almost all areas of technology. However, heat transfer analysis can be very difficult for complicated systems such as very large-scale integrated (VLSI) electric circuits and systems, making the simulation an attractive technique for studying heat transfer of those systems. This paper presents methods of heat transfer simulation using PSpice. First, typical heat transfer modes are discussed and heat transfer equations are presented. Then, equivalent electrical models are developed, and PSpice representations of those models are investigated. Finite-difference RC network models are developed and used for the simulation of complicated heat transfer problems using PSpice. Two typical heat transfer examples are studied. Simulations are performed to investigate and study the heat transfer and energy flow of the two examples using PSpice.

A Review of Recent Progress in Heat Transfer

1942 ◽  
Vol 148 (1) ◽  
pp. 81-112 ◽  
Author(s):  
C. H. Lander
Keyword(s):  
Heat Transfer ◽  
Aircraft Design ◽  
Nucleate Boiling ◽  
Film Condensation ◽  
The Past ◽  
Fluid Layers ◽  
Engineering Problems ◽  
Growth Of Knowledge ◽  
Transfer Problems ◽  
Made In

The state of knowledge of heat transfer in relation to mechanical engineering problems was summarized by Professor Dalby in a paper before the Institution in 1909. The present paper discusses the growth of knowledge during the past thirty years, and the ever-expanding fields of application. Complete rationalization is still not possible, but dimensional methods similar to those used in ship and aircraft design are being applied more and more generally to heat transfer problems. By their aid the practical range of any set of data may be greatly widened. For example, experiments made under pressure on surfaces only a few inches high may be used to deduce the heat transfer for surfaces several feet high at atmospheric pressure; or experiments made in gases may be used to predict the heat transfer in liquids. Selected cases dealt with in the paper are: forced convection for banks of tubes and beds of broken solids, and the relation between heat transfer and friction; natural convection from vertical and horizontal surfaces and across fluid layers; heat transfer in the drop and film condensation of steam, and in film and nucleate boiling; evaporation and its relation to convection; emissive powers of surfaces for radiation; and radiation from non-luminous gases.

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