Determination of transient temperature fields in thick-walled elements using the inverse method

Magdalena Jaremkiewicz,Artur Cebula

doi:10.1051/e3sconf/20171302007

Abstract

The purpose of this paper is to propose a method of determining the transient temperature of the inner surface of thick-walled elements. The method can be used to determine thermal stresses in pressure elements. An inverse marching method is proposed to determine the transient temperature of the thickwalled element inner surface with high accuracy. The inverse method was validated computationally. The comparison between the temperatures obtained from the direct heat conduction problem solution and the results obtained by means of the proposed inverse method is very satisfactory. The advantage of the method is the possibility of determining the heat transfer coefficient at a point on the exposed surface based on the local temperature distribution measured on the insulated outer surface. The heat transfer coefficient determined experimentally can be used to calculate thermal stresses in elements with a complex shape. The proposed method can be used in online computer systems to monitor temperature and thermal stresses in thick-walled pressure components because the computing time is very short.

Highlights

Unsteady-state thermal stresses arising in pressure elements cannot be calculated correctly without knowing the temperature of the fluid and the heat transfer coefficient on the inner surface of these elements
The heat transfer coefficient has a significant effect on the optimum rate of changes in the fluid temperature, which is determined from the condition of not exceeding the thermal stress value on the inner surface of the pressure element [1]
This paper presents a general method for determination of temperature, the heat flux density and the heat transfer coefficient on the inner surface of a thick-walled element

Summary

Introduction

Unsteady-state thermal stresses arising in pressure elements cannot be calculated correctly without knowing the temperature of the fluid and the heat transfer coefficient on the inner surface of these elements. The most common method for determining timedependent changes in the element surface temperature described in reference literature is based on solving the direct heat conduction problem analytically or numerically. In the case of elements with regular shapes, the two- or three-dimensional transient temperature field can be determined by solving the inverse heat conduction problem using marching methods [7, 8, 11, 12]. Using the heat transfer coefficient determined on the element inner surface and the fluid temperature [12], commercial programs based on the finite element method can be applied to calculate thermal stresses. Thermal stresses on the edges of holes or other places of stress concentration can be found

Identification of the temperature distribution in the flat thick-walled plate

Computational validation of the inverse method

. Conclusions