scholarly journals Heating of thick-walled steam header – an experimental study

2018 ◽  
Vol 240 ◽  
pp. 05029
Author(s):  
Tomasz Sobota
Keyword(s):  
Experimental Study ◽  
Heat Conduction ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Computer Systems ◽  
Inverse Heat Conduction Problem ◽  
Inverse Heat Conduction ◽  
Experimental Installation ◽  
On Line ◽  
Steam Header

The paper presented the description of the experimental installation for testing of the computer systems for on-line monitoring of the power boilers operation. The results of the experiment can be used for calculation of temperature and thermal stresses distribution in thick walled pressure elements based on the solution of the inverse heat conduction problem.

METHOD OF FUNDAMENTAL SOLUTION FOR AN INVERSE HEAT CONDUCTION PROBLEM WITH VARIABLE COEFFICIENTS

2013 ◽  
Vol 10 (02) ◽  
pp. 1341009 ◽  
Author(s):  
MING LI ◽  
XIANG-TUAN XIONG ◽  
YAN LI
Keyword(s):  
Heat Conduction ◽  
Heat Conduction Problem ◽  
Fundamental Solutions ◽  
Variable Coefficients ◽  
Inverse Heat Conduction Problem ◽  
Method Of Fundamental Solutions ◽  
Inverse Heat Conduction ◽  
Modified Method ◽  
On Line ◽  
Ill Posed

In this paper, we consider an inverse heat conduction problem with variable coefficient a(t). In many practical situations such as an on-line testing, we cannot know the initial condition for example because we have to estimate the problem for the heat process which was already started. Based on the method of fundamental solutions, we give a numerical scheme for solving the reconstruction problem. Since the governing equation contains variable coefficients, modified method of fundamental solutions was used to solve this kind of ill-posed problems. Some numerical examples are given for verifying the efficiency and accuracy of the presented method.

Analysis of Thermal Stresses in a Boiler Drum During Start-Up

1999 ◽  
Vol 121 (1) ◽  
pp. 84-93 ◽  
Author(s):  
J. Taler ◽  
B. We˛glowski ◽  
W. Zima ◽  
S. Gra˛dziel ◽  
M. Zborowski
Keyword(s):  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
New Method ◽  
Transient Temperature ◽  
Fluid Temperature ◽  
Inverse Heat Conduction ◽  
Vessel Elements

The paper presents an analytical way of calculating thermal stress distributions in cylindrical vessels, nonuniformly heated on their circumference. In thick-walled vessel elements, simplified analytical formulas do not give satisfactory results. A new method for determining thermal stresses has been developed. On the basis of temperature history measurements at several points on the drum outer surface, a time-space temperature distribution in the component cross section is determined, and next, thermal stresses are calculated using the finite element method (FEM). The new method, proposed for the solution of the inverse heat conduction problem, is sufficiently accurate. Knowledge of the boundary conditions on the inner surface of the drum, i.e., fluid temperature and heat transfer coefficient, is not necessary because the transient temperature distribution in the component is obtained from the solution of the inverse heat conduction problem. Comparison of the thermal distributions from FEM versus the new method demonstrate the accuracy of the new method. An example application of the new method demonstrates its benefits over the solution of the boundary-initial problem obtained by FEM.

Monitoring of thermal stresses in pressure components using inverse heat conduction methods

2017 ◽  
Vol 27 (3) ◽  
pp. 740-756 ◽  
Author(s):  
Jan Taler ◽  
Bohdan Weglowski ◽  
Marcin Pilarczyk
Keyword(s):  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Transient Temperature ◽  
Measured Temperature ◽  
Inverse Heat Conduction ◽  
Content Type ◽  
Start Up

Purpose The purpose of this paper is to present a method for monitoring transient thermal stresses. This paper also presents the analysis of thermal stresses of boiler pressure element heating during the start-up in real conditions. The inverse methods are used to determine the wall temperature, whereas the commercial software ANSYS is used to determine the thermal stresses in the pressure component. Design/methodology/approach The method is based on the solution of the inverse heat conduction problem. Thermal stresses are determined indirectly taking into account the measured temperature values at selected points on the outer wall of a pressure component. First, the transient temperature distribution in the entire pressure element is calculated, and then, thermal stresses are determined by the finite element method. Measured pressure changes are used to determine the stresses resultant from the internal pressure. Findings The obtained stresses and temperature in the thick-walled pipe are illustrated and compared with experimental data. Satisfactory agreement was found between computational and experimental results. Originality/value The method can be used in the monitoring of thermal and mechanical stresses during the boiler’s start-up and shut-down. Because the temperature distribution at each time level is determined, it can be applied as a thermal load during the structural analysis.

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