Numerical Simulation of Heat Conduction for Error Analysis on Heat Flux Sensor Embedded in Flat Steel Plate

2014 ◽  
Vol 563 ◽  
pp. 133-136
Author(s):  
Chun Lai Tian ◽  
Shan Zhou ◽  
Li Yong Han
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Heat Conduction ◽  
Temperature Difference ◽  
Heat Conduction Problem ◽  
Maximum Temperature ◽  
Heat Flux Sensor ◽  
Maximum Temperature Difference ◽  
Maximum Heat ◽  
Errors Analysis

A numerical simulation model of heat flux sensors embedded in a flat plate is established. Each sensor has four thermal couples and is inserted into the specified hole. The problem is defined as a steady heat conduction problem with specified boundary conditions and solved by the finite element method. The results of the simulation case demonstrate that the maximum heat flux appears near the sensor shell. The average heat flux of the plate is much smaller than the maximum. Due to exiting of the contact heat resistance, the temperature of the sensor is much lower than that of the plate at horizontal surface. The maximum temperature difference appears on the bottom shell of the sensor. The maximum temperature difference between the simulation results and the experimental data at test points is 1.5 K. The model is verified and could be accepted for the further errors analysis.

Nonequilibrium Thermal Response of Porous Media in Unsteady Heat Conduction With Sinusoidally Changing Boundary Temperature

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Huijin Xu ◽  
Liang Gong ◽  
Changying Zhao ◽  
Ying Yin
Keyword(s):  
Porous Media ◽  
Heat Conduction ◽  
Temperature Difference ◽  
Thermal Response ◽  
Porous Solid ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Boundary Temperature ◽  
Thermal Disturbance ◽  
Unsteady Heat Conduction

The thermal response of porous foam filled with a solid material was theoretically investigated under unsteady heat conduction with a sinusoidally changing boundary temperature. The local thermal nonequilibrium (LTNE) effect between the porous foam and the infill was obvious, and the two-equation model is employed for the unsteady heat conduction in porous-solid system. The temperature difference, which was defined as the time average of the absolute value of the difference between the temperatures of the porous solid and the infill, was proposed for quantitatively describing the LTNE effect in porous media. The LTNE phenomenon for unsteady heat conduction in porous media is influenced by the fluctuation period of the thermal boundary, foam morphology, and the thermal diffusivities of the porous solid and the infill. The LTNE effect of unsteady porous-media heat conduction was evident in the region near the thermal disturbance boundary. The maximum temperature difference was found on the curve of temperature difference versus fluctuation period, which means that the thermal response characteristics of porous composites resonate with periodically changing thermal disturbance. The fluctuation period corresponding to the maximum temperature difference has positive correlations with thermal diffusion resistance for unsteady porous-media heat conduction.

A General Analytical Approach for Defining Effectiveness in Ideal Two Fluid Heat Exchangers

2002 ◽  
Author(s):  
Devashish Shrivastava ◽  
Tim Ameel
Keyword(s):  
Heat Transfer ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Laws Of Thermodynamics ◽  
Analytical Development ◽  
Two Fluid

A general analytical development, based on the first and second laws of thermodynamics, is used to define the maximum possible heat transfer in an ideal two-fluid exchanger as well as the maximum possible temperature differences for both fluid streams. It is shown that the conventional expression for the maximum possible heat transfer in ideal two-fluid heat exchangers is a special case of the general expressions. The application of both the first and second laws of thermodynamics in defining the maximum possible heat transfer and maximum possible temperature difference provides only one expression (instead of two different expressions) for either stream which is a measure of both thermal and temperature effectiveness of the particular stream. Differences between the conventional and proposed effectiveness values are presented as functions of the capacity ratio and NTU. These data are used to demonstrate the advantages of the new definitions for maximum heat transfer and maximum temperature difference in ideal two-fluid heat exchangers.

MODELING THE EFFECT OF HEAT EXCHANGE ON THE EFFICIENCY OF A THERMOELECTRIC COOLER

2020 ◽  
Vol 2 ◽  
pp. 132-135
Author(s):  
O.I. MARKOV
Keyword(s):  
Numerical Calculation ◽  
Heat Exchange ◽  
Solid State ◽  
Numerical Modelling ◽  
Temperature Difference ◽  
Maximum Temperature ◽  
Thermoelectric Cooler ◽  
Maximum Temperature Difference ◽  
Peltier Cooler ◽  
Account Heat

Numerical modelling thermal and thermoelectric processes in a branch of solid–state thermoelectric of Peltier cooler is performed, taking into account heat exchange by convection and radiation. The numerical calculation of the branch was carried out in the mode of the maximum temperature difference.

Optimization of a radiant system for hydrothermal performance using Taguchi and utility concept

2021 ◽  
pp. 1-29
Author(s):  
Ratnadeep Nath ◽  
Vikas Verma ◽  
Rahul Tarodiya
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Temperature Difference ◽  
Wall Temperature ◽  
Thermal Parameters ◽  
Conventional Heating ◽  
Geometrical Parameters ◽  
Maximum Heat ◽  
Utility Concept ◽  
Heating Mode

Abstract Radiant floor panel technology is gaining popularity as an alternative system over conventional heating, ventilation and, air conditioning system (HVAC) to maintain the room temperature for the desired comfort. This research paper aims to optimize the hydrothermal performance of a radiant system by implementing the Taguchi technique and utility concept for cooling and heating mode of operation. Five geometrical and thermal parameters such as pipe diameter, pipe spacing, concrete layer thickness, wall temperature, and inlet and outlet water temperature difference with three levels are chosen as controlling factors to perform optimization. Considering five parameters and three levels, a total of 27 trial runs (L27) are constructed and computed by mathematical calculation. Two different sets of optimum parameters are obtained for maximizing heat flux and minimizing pressure drop. Further, the utility concept is employed to get a single set of parameters to achieve maximum utilization of the radiant system. Taguchi analysis revealed that thermal parameters like temperature difference and wall temperature are the most influential parameters to reach maximum heat transfer and minimum pressure drop followed by geometrical parameters like pipe spacing and diameter for heat flux and pressure drop, respectively. Providing more weightage to heat flux than pressure drop, utility analysis showed 32% and 42% augmentation in heat flux for cooling and heating mode respectively, at the cost of an increase in pressure drop.

Simulation and Optimization of Temperature Field of Tank Cover with Super Large Diameter during the Creep Aging Forming Process

2021 ◽  
Vol 315 ◽  
pp. 3-9
Author(s):  
Yuan Gao ◽  
Li Hua Zhan ◽  
Hai Long Liao ◽  
Xue Ying Chen ◽  
Ming Hui Huang
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Temperature Difference ◽  
Single Stage ◽  
Maximum Temperature ◽  
Heating Process ◽  
Temperature Field Distribution ◽  
Two Stage ◽  
Maximum Temperature Difference ◽  
Forming Accuracy

The uniformity of temperature field distribution in creep aging process is very important to the forming accuracy of components. In this paper, the temperature field distribution of 2219 aluminum alloy tank cover during aging forming is simulated by using the finite element software FLUENT, and a two-stage heating process is proposed to reduce the temperature field distribution heterogeneity. The results show that the temperature difference of the tank cover is large in the single-stage heating process, and the maximum temperature difference is above 27°C,which seriously affects the forming accuracy of the tank cover. With two-stage heating process, the temperature difference in the first stage has almost no direct impact on the forming accuracy of the top cover. In the second stage, the temperature difference of the tank cover is controlled within 10°C, compared with the single-stage heating, the maximum temperature difference is reduced by more than 17°C. The two-stage heating effectively reduces the heterogeneity of the temperature field of the top cover. The research provides technical support for the precise thermal mechanical coupling of large-scale creep aging forming components.

scholarly journals A Fractional Single-Phase-Lag Model of Heat Conduction for Describing Propagation of the Maximum Temperature in a Finite Medium

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 876 ◽  
Author(s):  
Stanisław Kukla ◽  
Urszula Siedlecka
Keyword(s):  
Heat Conduction ◽  
Hollow Cylinder ◽  
Single Phase ◽  
Heat Conduction Problem ◽  
Expansion Method ◽  
Maximum Temperature ◽  
Phase Lag ◽  
Conduction Model ◽  
Laplace Transform Technique ◽  
Finite Medium

In this paper, an investigation of the maximum temperature propagation in a finite medium is presented. The heat conduction in the medium was modelled by using a single-phase-lag equation with fractional Caputo derivatives. The formulation and solution of the problem concern the heat conduction in a slab, a hollow cylinder, and a hollow sphere, which are subjected to a heat source represented by the Robotnov function and a harmonically varying ambient temperature. The problem with time-dependent Robin and homogenous Neumann boundary conditions has been solved by using an eigenfunction expansion method and the Laplace transform technique. The solution of the heat conduction problem was used for determination of the maximum temperature trajectories. The trajectories and propagation speeds of the temperature maxima in the medium depend on the order of fractional derivatives occurring in the heat conduction model. These dependencies for the heat conduction in the hollow cylinder have been numerically investigated.

Nonlinear Inverse Heat Conduction With a Moving Boundary: Heat Flux and Surface Recession Estimation

1999 ◽  
Vol 121 (3) ◽  
pp. 708-711 ◽  
Author(s):  
V. Petrushevsky ◽  
S. Cohen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fourier Series ◽  
Heat Conduction ◽  
Moving Boundary ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Variable Order ◽  
Inverse Heat Conduction ◽  
One Dimensional

A one-dimensional, nonlinear inverse heat conduction problem with surface ablation is considered. In-depth temperature measurements are used to restore the heat flux and the surface recession history. The presented method elaborates a whole domain, parameter estimation approach with the heat flux approximated by Fourier series. Two versions of the method are proposed: with a constant order and with a variable order of the Fourier series. The surface recession is found by a direct heat transfer solution under the estimated heat flux.

Applying Neural Networks to the Solution of the Inverse Heat Conduction Problem in a Gun Barrel

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Y. Hwang ◽  
S. Deng
Keyword(s):  
Neural Network ◽  
Heat Flux ◽  
Heat Conduction ◽  
Heat Conduction Problem ◽  
Nonlinear Function ◽  
Inverse Heat Conduction ◽  
Unknown Parameters ◽  
Acceptable Error ◽  
Gun Barrel ◽  
Inverse Heat Conduction Problems

The primary cause of gun barrel erosion is the heat generated by the shell as its travels along the barrel. Therefore, calculating the heat flux input to the gun bore is very important when investigating wear problems in the gun barrel and examining its thermomechanical properties. This paper employs the continuous-time analog Hopfield neural network (CHNN) to compute the temperature distribution in various forward heat conduction problems. An efficient technique is then proposed for the solution of inverse heat conduction problems using a three-layered backpropagation neural network (BPN). The weak generalization capacity of BPN networks when applied to the solution of nonlinear function approximations is improved by employing the Bayesian regularization algorithm. The CHNN scheme is used to calculate the temperature in a 155mm gun barrel and the trained BPN is then used to estimate the heat flux of the inner surface of the barrel. The results show that the proposed neural network analysis method successfully solves forward heat conduction problems and is capable of predicting the unknown parameters in inverse problems with an acceptable error.

Heat Conduction Rectification in Nanostructure With Step Change in Cross-Section

2010 ◽  
Author(s):  
Xingang Liang ◽  
Bao Yue
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Thermal Resistance ◽  
Cross Section ◽  
Temperature Difference ◽  
Flow Direction ◽  
Step Change ◽  
Dynamics Simulation ◽  
Rectification Effect ◽  
Thick Part

Heat conduction rectifier is attracting more attention due to its potential application to process thermal currents independently and convert them into electronic signals. This work reports an investigation by molecular dynamics simulation on the heat conduction rectification effect in the nanostructure whose cross-section have step change along the heat flux. It is found that thermal resistance is different with reversed heat flux direction, which is called the heat conduction rectification. The heat conduction rectification depends on the temperature difference. By reducing temperature difference across the nanostructure, the rectification could be reversed. When the temperature difference is small enough, the thermal resistance is larger when the heat flux flows from the thick part to the thin part when the length of the structure is about 10 nm. The larger variation in the cross-section leads the larger difference in the thermal resistance with opposite heat flux. The mechanism of the rectification is discussed. If we take phonons as liquid particles and consider the case of a liquid flowing through a channel with step expansion in cross-section, the flow resistance is less with liquid flowing from the narrow part to the wide part than that in the case with contrary flow direction. In fact, the scattering of phonons at the step face reduces the mean free path of phonon when heat flux conducts from the narrow end to the wide end.

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