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.

scholarly journals Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method

2011 ◽  
Vol 32 (3) ◽  
pp. 191-200 ◽  
Author(s):  
sławomir Grądziel
Keyword(s):  
Boundary Condition ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Thermal Boundary Condition ◽  
Transient Temperature ◽  
Inverse Heat Conduction ◽  
Transient Temperature Distribution ◽  
Power Boiler

Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method The following paper presents the method for solving one-dimensional inverse boundary heat conduction problems. The method is used to estimate the unknown thermal boundary condition on inner surface of a thick-walled Y-branch. Solution is based on measured temperature transients at two points inside the element's wall thickness. Y-branch is installed in a fresh steam pipeline in a power plant in Poland. Determination of an unknown boundary condition allows for the calculation of transient temperature distribution in the whole element. Next, stresses caused by non-uniform transient temperature distribution and by steam pressure inside a Y-branch are calculated using the finite element method. The proposed algorithm can be used for thermal-strength state monitoring in similar elements, when it is not possible to determine a 3-D thermal boundary condition. The calculated temperature and stress transients can be used for the calculation of element durability. More accurate temperature and stress monitoring will contribute to a substantial decrease of maximal stresses that occur during transient start-up and shut-down processes.

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.

A Method for the Solution of the Coupled Inverse Heat Conduction-Radiation Problem

1996 ◽  
Vol 118 (1) ◽  
pp. 10-17 ◽  
Author(s):  
N. J. Ruperti ◽  
M. Raynaud ◽  
J. F. Sacadura
Keyword(s):  
Heat Conduction ◽  
Inverse Method ◽  
Radiative Heat ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Transient Temperature ◽  
Test Cases ◽  
Inverse Heat Conduction ◽  
Radiation Problem ◽  
Transfer Mode

The inverse problem of estimating surface temperatures and fluxes from simulated transient temperature measured within a semitransparent slab is studied. A space-marching technique, whose performance is already known for the solution of the inverse heat conduction problem (IHCP), is adapted to solve an inverse heat conduction-radiation problem (IHCRP). An iterative algorithm is proposed. Different values of the conduction-to-radiation parameter are considered in order to show, with benchmark test cases, the effects of the radiative heat transfer mode on the performance of the inverse method.

Numerical Solution of the General Two-Dimensional Inverse Heat Conduction Problem (IHCP)

1997 ◽  
Vol 119 (1) ◽  
pp. 38-45 ◽  
Author(s):  
A. M. Osman ◽  
K. J. Dowding ◽  
J. V. Beck
Keyword(s):  
Experimental Data ◽  
Heat Conduction ◽  
Heat Conduction Problem ◽  
Regularization Parameter ◽  
Simulated Data ◽  
Inverse Heat Conduction Problem ◽  
Transient Temperature ◽  
Two Dimensional ◽  
Inverse Heat Conduction ◽  
Temperature Dependent

This paper presents a method for calculating the heat flux at the surface of a body from experimentally measured transient temperature data, which has been called the inverse heat conduction problem (IHCP). The analysis allows for two-dimensional heat flow in an arbitrarily shaped body and orthotropic temperature dependent thermal properties. A combined function specification and regularization method is used to solve the IHCP with a sequential-in-time concept used to improve the computational efficiency. To enhance the accuracy, the future information used in the sequential-in-time method and the regularization parameter are variable during the analysis. An example using numerically simulated data is presented to demonstrate the application of the method. Finally, a case using actual experimental data is presented. For this case, the boundary condition was experimentally measured and hence, it was known. A good comparison is demonstrated between the known and estimated boundary conditions for the analysis of the numerical, as well as the experimental data.

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