Temperature Distributions and Thermal Stresses in Asymmetrically Heat Radiated Tubes

1986 ◽  
Vol 53 (1) ◽  
pp. 116-120 ◽  
Author(s):  
T. Fett
Keyword(s):  
Heat Flux ◽  
Half Space ◽  
Flux Distribution ◽  
Thermal Stresses ◽  
Tube Wall ◽  
Stress Distributions ◽  
Heat Flux Distribution ◽  
Temperature Distributions

The transient and stationary temperature distributions in a tube wall caused by an asymmetrical heat flux distribution are evaluated. The results are represented for the case of a heat radiating half-space. In addition, the accompanying stress distributions are computed.

Heat Flux Distribution Over a Solar Central Receiver Using an Aiming Strategy Based on a Conventional Closed Control Loop

2017 ◽  
Author(s):  
Jesús García ◽  
Yen Chean Soo Too ◽  
Ricardo Vasquez Padilla ◽  
Rodrigo Barraza Vicencio ◽  
Andrew Beath ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flux Distribution ◽  
Thermal Stresses ◽  
Control Strategies ◽  
Multiple Input Multiple Output ◽  
Control Loop ◽  
Heat Flux Distribution ◽  
Input Multiple Output ◽  
Solar Receiver ◽  
Solar Field

Solar thermal towers are a maturing technology that have the potential to supply a significant part of energy requirements of the future. One of the issues that needs careful attention is the heat flux distribution over the central receiver’s surface. It is imperative to maintain receiver’s thermal stresses below the material limits. Therefore, an adequate aiming strategy for each mirror is crucial. Due to the large number of mirrors present in a solar field, most aiming strategies work using a data base that establishes an aiming point for each mirror depending on the relative position of the sun and heat flux models. This paper proposes a multiple-input multiple-output (MIMO) closed control loop based on a methodology that allows using conventional control strategies such as those based on Proportional Integral Derivative (PID) controllers. Results indicate that even this basic control loop can successfully distribute heat flux on the solar receiver.

The Temperature Field Around a Spherical Ridge or Trough in a Plane

1992 ◽  
Vol 114 (2) ◽  
pp. 317-325 ◽  
Author(s):  
J. Fransaer ◽  
J. R. Roos
Keyword(s):  
Heat Flux ◽  
Contact Angle ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Flux Distribution ◽  
Spherical Particles ◽  
Heat Flux Distribution ◽  
Conducting Plane ◽  
Temperature Distributions ◽  
Random Array

An analytical solution, which describes the temperature field around a single spherical particle partly embedded in a plane or around a trough making an arbitrary contact angle with a plane, is presented here. The temperature distributions for three cases are studied: the temperature distribution around a conducting bowl or trough, the temperature distribution around a non-conducting bowl or trough present in a conducting plane, and the temperature profile around a conducting bowl or trough conducting heat toward a sink at infinity. The normalized heat flux distribution on the plane and particle is presented. The various incremental resistances caused by a single and a dilute planar random array of truncated spherical particles are also derived.

Thermal Resistance Models for Non-Circular Moving Heat Sources on a Half Space

2001 ◽  
Vol 123 (4) ◽  
pp. 624-632 ◽  
Author(s):  
Y. S. Muzychka ◽  
M. M. Yovanovich
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Half Space ◽  
Flux Distribution ◽  
Numerical Solutions ◽  
Characteristic Length ◽  
Heat Sources ◽  
Characteristic Length Scale ◽  
Heat Flux Distribution ◽  
Proposed Model

Solutions to stationary and moving heat sources on a half space are reviewed for rectangular and elliptic contacts. The effects of shape, heat flux distribution, and orientation with respect to the direction of motion are examined. The dimensionless thermal resistance is shown to be a weak function of heat source shape if the square root of contact area is used as a characteristic length scale. Simple expressions are developed for calculating total thermal resistances of non-circular moving heat sources by combining asymptotic solutions for large and small values of the Peclet number. Both uniform and parabolic heat flux distributions are examined. A model is developed for predicting average or maximum flash temperatures of real sliding contacts. Comparisons of the proposed model are made with numerical solutions for two cases involving non-circular contacts.

Inverse Thermal Analysis of a Coke Drum Using a Bayesian Probabilistic Approach

2015 ◽  
Author(s):  
Edrissa Gassama ◽  
Charles Panzarella ◽  
Jeffrey Cochran
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Temperature Distribution ◽  
Flux Distribution ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Probabilistic Approach ◽  
Operating Conditions ◽  
Heat Flux Distribution ◽  
Posterior Probability Distribution

There is much interest in predicting the optimal operating conditions of a coke drum in order to extend its life and optimize both maintenance and repair. Typically, only temperature measurements on the outer surface of the wall are available from monitoring. In order to predict damage due to thermal stresses and other mechanisms, the temperature distribution through the wall is required. This could be determined if the heat flux on the inner surface of the wall were known, but this is difficult to obtain directly. In this paper, the heat flux distribution on the inner wall is determined solely from thermocouple measurements taken on the outside of the wall by solving a stochastic inverse heat conduction problem (IHCP). A finite element analysis is used to solve the forward thermal problem, and a Bayesian inference approach is used to model the posterior probability distribution of the heat flux. A newly developed probabilistic sampling technique known as the Particle Raking Algorithm (PRA) is found to be quite effective at solving this inverse problem. Once determined, the heat flux distribution is then applied as a boundary condition for the finite element model to determine the through-wall temperature distribution.

Studies on heat flux distribution on the membrane walls in a 600 MW supercritical arch-fired boiler

2016 ◽  
Vol 103 ◽  
pp. 264-273 ◽  
Author(s):  
Dalong Zhang ◽  
Chenwei Meng ◽  
Hai Zhang ◽  
Pengyuan Liu ◽  
Zhouhang Li ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flux Distribution ◽  
Heat Flux Distribution

Research on Heat Flux Distribution in Deep Grinding

2008 ◽  
Author(s):  
D. H. Zhu ◽  
B. Z. Li ◽  
J. G. Yang
Keyword(s):  
Heat Flux ◽  
Flux Distribution ◽  
Theoretical Expression ◽  
Uniform Heat Flux ◽  
Heat Transfer Mechanism ◽  
Heat Flux Distribution ◽  
Workpiece Surface ◽  
Quadratic Curve ◽  
Flux Model ◽  
Heat Flux Model

This paper studies the heat transfer mechanism in deep grinding process, especially the heat flux to the workpiece. On the basis of triangle moving heat source, a quadratic curve heat flux model in the grinding zone was developed to determine the heat flux distribution and to estimate the surface temperature of workpiece. From the calculated theoretical expression of heat flux to the workpiece, the quadratic curve heat flux can be understood as the superposition of square law heat flux, triangular heat flux and uniform heat flux in the grinding zone. Then four heat flux models using the determined amount of heat flux were applied to estimate the workpiece surface temperatures which were compared with that measured by the embedded thermocouple. It has been found that the quadratic curve heat flux distribution seems to give the best match with measured and theoretical temperature, although square law heat flux model is good enough to predict the temperature.

scholarly journals Thermal analysis in thin-film fluid regions of rectangular microgroove

2018 ◽  
Vol 22 (2) ◽  
pp. 899-897
Author(s):  
Xiaohong Gui ◽  
Xiange Song ◽  
Baisheng Nie
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Contact Angle ◽  
Film Thickness ◽  
Flux Distribution ◽  
Total Heat ◽  
Heat Flux Distribution ◽  
Total Heat Transfer ◽  
Thin Film Thickness

The effects of contact angle and superheat on thin-film thickness and heat flux distribution occurring in a rectangle microgroove are numerically simulated. Accordingly, physical, and mathematical models are built in detail. Numerical results indicate that meniscus radius and thin-film thickness increase with the improvement of contact angle. The heat flux distribution in the thin-film region increases non-linearly as the contact angle decreases. The total heat transfer through the thin-film region increases with the improvement of superheat, and decreases as the contact angle increases. When the contact angle is equal to zero, the heat transfer in the thin-film region accounts for more than 80% of the total heat transfer. Intensive evaporation in the thin-film region plays a key role in heat transfer for the rectangle capillary microgroove. The liquid with higher wetting performance is more capable of playing the advantages of higher intensity heat transfer in thin- film region. The current investigation will result in a better understanding of thin- -film evaporation and its effect on the effective thermal conductivity in the rectangle microgroove.

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