Transient Thermal Stresses in Slabs and Circular Pressure Vessels

1953 ◽  
Vol 20 (2) ◽  
pp. 261-269
Author(s):  
M. P. Heisler
Keyword(s):  
Thermal Shock ◽  
Thermal Stresses ◽  
Pressure Vessels ◽  
Transient Temperature ◽  
Thermal Processes ◽  
Integral Theorem ◽  
Dimensionless Stress ◽  
Optimum Heating ◽  
Transient Thermal

Abstract This paper presents the results of computations for determining transient thermal stresses in slabs and circular pressure vessels. The process of solution adopted is to substitute transient-temperature formulas into the already available stress expressions. The expressions for thermal shock are transformed by means of a simple integral theorem into a form appropriate for analyzing the thermal processes commonly used to relieve thermal shock. A new dimensionless stress parameter is defined and applied to the determination of optimum heating or cooling times of massive pressure vessels.

scholarly journals Online Determining Heat Transfer Coefficient for Monitoring Transient Thermal Stresses

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 704
Author(s):  
Magdalena Jaremkiewicz ◽  
Jan Taler
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Computer Calculation ◽  
Transient Temperature ◽  
Unsteady Temperature ◽  
The Heat Transfer Coefficient

This paper proposes an effective method for determining thermal stresses in structural elements with a three-dimensional transient temperature field. This is the situation in the case of pressure elements of complex shapes. When the thermal stresses are determined by the finite element method (FEM), the temperature of the fluid and the heat transfer coefficient on the internal surface must be known. Both values are very difficult to determine under industrial conditions. In this paper, an inverse space marching method was proposed for the determination of the heat transfer coefficient on the active surface of the thick-walled plate. The temperature and heat flux on the exposed surface were obtained by measuring the unsteady temperature in a small region on the insulated external surface of a pressure component that is easily accessible. Three different procedures for the determination of the heat transfer coefficient on the water-spray surface were presented, with the division of the plate into three or four finite volumes in the normal direction to the plate surface. Calculation and experimental tests were carried out in order to validate the method. The results of the measurements and calculations agreed very well. The computer calculation time is short, so the technique can be used for online stress determination. The proposed method can be applied to monitor thermal stresses in the components of the power unit in thermal power plants, both conventional and nuclear.

scholarly journals Determination of Transient Fluid Temperature and Thermal Stresses in Pressure Thick-Walled Elements Using a New Design Thermometer

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 222 ◽  
Author(s):  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Piotr Dzierwa ◽  
Jan Taler
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Critical Pressure ◽  
Thermal Stresses ◽  
Thermal Inertia ◽  
Internal Surface ◽  
Transient Temperature ◽  
Fluid Temperature ◽  
Start Up

In both conventional and nuclear power plants, the high thermal load of thick-walled elements occurs during start-up and shutdown. Therefore, thermal stresses should be determined on-line during plant start-up to avoid shortening the lifetime of critical pressure elements. It is necessary to know the fluid temperature and heat transfer coefficient on the internal surface of the elements, which vary over time to determine transient temperature distribution and thermal stresses in boilers critical pressure elements. For this reason, accurate measurement of transient fluid temperature is very significant, and the correct determination of transient thermal stresses depends to a large extent on it. However, thermometers used in power plants are not able to measure the transient fluid temperature with adequate accuracy due to their massive housing and high thermal inertia. The article aims to present a new technique of measuring transient superheated steam temperature and the results of its application on a real object.

scholarly journals Thermal-Stress Ratchet Mechanism in Pressure Vessels

1959 ◽  
Vol 81 (2) ◽  
pp. 190-194 ◽  
Author(s):  
D. R. Miller
Keyword(s):  
Growth Rate ◽  
Thermal Stress ◽  
Internal Pressure ◽  
Strain Hardening ◽  
Thermal Stresses ◽  
Pressure Vessels ◽  
Progressive Reduction ◽  
Ratchet Mechanism

The combination of cyclic thermal stresses and sustained internal pressure in a vessel is shown to be a source of progressive expansion of the vessel if the stresses are sufficiently high. Criteria presented allow determination of limits to be imposed on stresses in order to prevent progressive expansion or to allow estimation of the expansion per cycle where stresses are sufficient to produce growth. The effect of strain-hardening of the metal on progressive reduction of the growth rate is discussed.

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.

Transient Thermal Stresses in a Semi-Infinite Slab

1960 ◽  
Vol 27 (1) ◽  
pp. 93-103 ◽  
Author(s):  
W. Jaunzemis ◽  
E. Sternberg
Keyword(s):  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Theory Of Elasticity ◽  
Transient Temperature ◽  
Finite Segment ◽  
Infinite Slab ◽  
In Series ◽  
Transient Thermal ◽  
External Loads ◽  
Uniform Change

This investigation is concerned with the transient temperature and thermal-stress distribution generated in a semi-infinite slab if a finite segment of its edge is subjected to a sudden uniform change in temperature. The slab is supposed to be free from external loads and its faces are assumed to be insulated. Exact solutions in series form are obtained both for the heat-conduction problem and for the associated thermoelastic problem. The latter is treated quasi-statically within the classical two-dimensional theory of elasticity. The thermal stresses appropriate to the generalized plane-stress solution vanish identically in the limit as time tends to infinity. The space and time dependence of these stresses is examined in some detail with a view toward tracing the evolution of this well-known, steady-state degeneracy. Finally, the results corresponding to an instantaneous heating or cooling of a portion of the boundary are used to study the effect upon the stresses of gradual changes in the surface temperature.

Transient Thermal Stresses on a Finite Disk Due to a Continuous Point Heat Source

1970 ◽  
Vol 92 (2) ◽  
pp. 357-365 ◽  
Author(s):  
T. R. Hsu
Keyword(s):  
Heat Source ◽  
Thermal Stresses ◽  
Circular Disk ◽  
Transient Temperature ◽  
Point Heat Source ◽  
Finite Radius ◽  
Transient Temperature Distribution ◽  
Instantaneous Point ◽  
Continuous Point ◽  
Transient Thermal

This paper contains exact solutions for the transient temperature distribution and the associated quasi-static thermal stresses and deformations which arise in a thin circular disk of finite radius subjected to a continuous point heat source acting on its periphery. It has been proven in this paper that the solutions of this type of problem may be obtained by integrating the time variable of the corresponding solutions in the case of an instantaneous point heat source. The solutions are given in the form of double infinite series and graphical representations of the solutions in dimensionless terms are included. Reference is made to methods of applying the solutions to shapes other than disks. The solutions are pertinent to problems which occur in welding engineering and modern nuclear technology.

Thermal Shock Behavior of a Functionally Graded Material Plate with a Crack

2013 ◽  
Vol 275-277 ◽  
pp. 152-155 ◽  
Author(s):  
Yan Yan Zhang ◽  
Li Cheng Guo ◽  
Feng Nan Guo ◽  
Hong Jun Yu ◽  
Kai Huang ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Functionally Graded Material ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Transient Temperature ◽  
The Finite Element Method ◽  
Graded Material ◽  
Thermal Shock Behavior ◽  
Transient Thermal ◽  
Thermal Shock Problem

A thermal shock problem of a functionally graded material plane (FGMP) containing a crack is considered. All the material properties of the FGMP are assumed to be dependent on the coordinates.The transient temperature fields are solved by combining the finite difference method (FDM) and the finite element method (FEM). Then the transient thermal stress intensity factors (TSIFs) are obtained using the interaction energy integral method. The transient characteristics of the TSIFs are investigated.

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