Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe

Thermal fatigue cracking may initiate at a T-junction pipe where high and low temperature fluids flow in from different directions and mix. Thermal stress is caused by a temperature gradient in a structure and by its variation. In this study, an experimental method was developed to estimate stress d...

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Autores principales:	Koji MIYOSHI, Akira NAKAMURA, Nobuyuki TAKENAKA
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2014
Materias:	thermal fatigue t-junction pipe temperature fluctuation numerical simulation thermocouple braze Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/6ee57cf513f5473f9bffce5c37da7156
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spelling	oai:doaj.org-article:6ee57cf513f5473f9bffce5c37da71562021-11-26T06:04:01ZNumerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe2187-974510.1299/mej.2014tep0006https://doaj.org/article/6ee57cf513f5473f9bffce5c37da71562014-04-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/1/2/1_2014tep0006/_pdf/-char/enhttps://doaj.org/toc/2187-9745Thermal fatigue cracking may initiate at a T-junction pipe where high and low temperature fluids flow in from different directions and mix. Thermal stress is caused by a temperature gradient in a structure and by its variation. In this study, an experimental method was developed to estimate stress distributions at a T-junction pipe. FEM analysis and experiments to measure wall temperatures at the inner surface of the pipe with thermocouples were used in this method. The numerical simulations were performed to decide the optimum measuring points in the axial and circumferential directions for thermocouples. The numerical simulation results also showed that the attenuation of temperature amplitude and phase delay from the inner surface to the thermocouple measurement points was not negligible for 0.5 mm diameter sheathed thermocouples. A transfer function was calculated to obtain wall temperatures at the inner surface from measured data. In addition, the numerical simulation results showed that the amplitude and the phase of temperature fluctuations differed depending on existence of voids around thermocouples. These results showed that thermocouples should be installed in pipes without voids to measure accurate temperature fluctuations. It was confirmed that the voids disappeared when thermocouples were brazed in a vacuum atmosphere. Such thermocouples are expected to provide reliable experimental data from which the proper thermal stress distributions can be estimated by this method.Koji MIYOSHIAkira NAKAMURANobuyuki TAKENAKAThe Japan Society of Mechanical Engineersarticlethermal fatiguet-junction pipetemperature fluctuationnumerical simulationthermocouplebrazeMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 1, Iss 2, Pp TEP0006-TEP0006 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	thermal fatigue t-junction pipe temperature fluctuation numerical simulation thermocouple braze Mechanical engineering and machinery TJ1-1570
spellingShingle	thermal fatigue t-junction pipe temperature fluctuation numerical simulation thermocouple braze Mechanical engineering and machinery TJ1-1570 Koji MIYOSHI Akira NAKAMURA Nobuyuki TAKENAKA Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
description	Thermal fatigue cracking may initiate at a T-junction pipe where high and low temperature fluids flow in from different directions and mix. Thermal stress is caused by a temperature gradient in a structure and by its variation. In this study, an experimental method was developed to estimate stress distributions at a T-junction pipe. FEM analysis and experiments to measure wall temperatures at the inner surface of the pipe with thermocouples were used in this method. The numerical simulations were performed to decide the optimum measuring points in the axial and circumferential directions for thermocouples. The numerical simulation results also showed that the attenuation of temperature amplitude and phase delay from the inner surface to the thermocouple measurement points was not negligible for 0.5 mm diameter sheathed thermocouples. A transfer function was calculated to obtain wall temperatures at the inner surface from measured data. In addition, the numerical simulation results showed that the amplitude and the phase of temperature fluctuations differed depending on existence of voids around thermocouples. These results showed that thermocouples should be installed in pipes without voids to measure accurate temperature fluctuations. It was confirmed that the voids disappeared when thermocouples were brazed in a vacuum atmosphere. Such thermocouples are expected to provide reliable experimental data from which the proper thermal stress distributions can be estimated by this method.
format	article
author	Koji MIYOSHI Akira NAKAMURA Nobuyuki TAKENAKA
author_facet	Koji MIYOSHI Akira NAKAMURA Nobuyuki TAKENAKA
author_sort	Koji MIYOSHI
title	Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
title_short	Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
title_full	Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
title_fullStr	Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
title_full_unstemmed	Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe
title_sort	numerical evaluation of wall temperature measurement method developed to estimate thermal stress at t-junction pipe
publisher	The Japan Society of Mechanical Engineers
publishDate	2014
url	https://doaj.org/article/6ee57cf513f5473f9bffce5c37da7156
work_keys_str_mv	AT kojimiyoshi numericalevaluationofwalltemperaturemeasurementmethoddevelopedtoestimatethermalstressattjunctionpipe AT akiranakamura numericalevaluationofwalltemperaturemeasurementmethoddevelopedtoestimatethermalstressattjunctionpipe AT nobuyukitakenaka numericalevaluationofwalltemperaturemeasurementmethoddevelopedtoestimatethermalstressattjunctionpipe
_version_	1718409782589652992

Numerical evaluation of wall temperature measurement method developed to estimate thermal stress at T-junction pipe

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