Temperature fluctuations caused by the mixing of hot and cold streams at tee junctions may lead to high cycle thermal fatigue (HCTF) failure. It is necessary to evaluate the integrity of structures where the HCTF may occur. Therefore, the Japan Society of Mechanical Engineers (JSME) published “Guideline for Evaluation of High Cycle Thermal Fatigue of a Pipe (JSME S017),” in 2003, which provides the procedures and methods for evaluating the integrity of structures with the potential for HCTF. In JSME S017, one of the important procedures of thermal fatigue evaluation is to classify the flow patterns at tee junctions, because the degree of thermal fatigue damage is closely related to the flow pattern downstream of the mixing junction. The conventional characteristic equations for classifying flow patterns are only applicable to 90-deg tee junctions (T-junctions). However, angled tee junctions other than 90 deg (Y-junctions) are also used in chemical plants and refineries for reducing the pressure drop in the mixing zone and for weakening the force of the impingement of the branch pipe stream against the main pipe. The aim of this paper is to develop general characteristic equations applicable to both T- and Y-junctions. In this paper, general characteristic equations have been proposed based on the momentum ratio for all angles of tee junctions. Further, the validity of the proposed characteristic equations and their applicability to all angles of tee junctions have been confirmed using computational fluid dynamics (CFD) simulations. The results have also highlighted that the angle of the branch pipe has a significant effect on increasing the velocity ratio range for less damaging deflecting jet flow pattern, which is an important finding that could be used to extend the current design options for piping systems where HCTF may be a concern. In addition, categorization 3 is recommended as a more proper method for classifying flow patterns at tee junctions when evaluating the potential for thermal fatigue.

References

References
1.
Gelineau
,
O.
,
Escaravage
,
C.
,
Simoneau
,
J. P.
, and
Faidy
,
C.
,
2001
, “
High Cycle Thermal Fatigue: Experience and State of the Art in French LMFRs
,” Trans. of 16th Int. Conference on Structural Mechanics in Reactor Technology (SMiRT-16), Washington DC, Paper No. 1311, pp. 1–7.
2.
Faidy
,
C.
,
Courtois
,
T.
,
Fraguier
,
E.
,
Leduff, J.
,
Lefrancois, A.
, and
Dechelotte, J.
,
2000
, “
Thermal Fatigue in French RHR System
,”
International Conference on Fatigue of Reactor Components
, Napa, CA.
3.
Japan Nuclear Energy Safety Organization (JNES) (ed.), 2003, “Troubles in the Nuclear Power Plants in Japan,” http://www2.jnes.go.jp/atom-db/jp/index.html
4.
Maegawa
,
M.
,
2006
, “
Thermal Fatigue of Quench Hydrogen Piping
,”
19th Symposium on the Maintenance of Equipments (The Japan Petroleum Institute)
, Tokyo, Japan, pp. 12–17.
5.
The Japan Society of Mechanical Engineers (JSME),
2003
, “Guideline for Evaluation of High-Cycle Thermal Fatigue of a Pipe” (in Japanese), JSME S017.
6.
Wakamatsu
,
M.
,
Hirayama
,
H.
,
Kimura
,
K.
,
Ogura, K.
,
Shiina, K.
,
Tanimoto, K.
,
Mizutani, J.
,
Minami, Y.
,
Moriya, S.
, and
Madarame, H.
,
2003
, “
Study on High-Cycle Fatigue Evaluation for Thermal Striping in Mixing Tees With Hot and Cold Water (1)
,” ICONE11, Tokyo, Japan, ICONE11-36208.
7.
Kamide
,
H.
,
Igarashi
,
M.
,
Kawashima
,
S.
,
Kimura
,
N.
, and
Hayashi
,
K.
,
2009
, “
Study on Mixing Behavior in a Tee Piping and Numerical Analyses for Evaluation of Thermal Striping
,”
Nucl. Eng. Des.
,
239
, pp.
58
67
.10.1016/j.nucengdes.2008.09.005
8.
Lee
,
J. K.
,
Hu
,
L.
,
Saha
,
P.
, and
Kazimi
,
M. S.
,
2009
, “
Numerical Analysis of Thermal Striping Induced High Cycle Thermal Fatigue in a Mixing Tee
,”
Nucl. Eng. Des.
,
239
, pp.
833
839
.10.1016/j.nucengdes.2008.06.014
9.
Hu
,
L.
, and
Kazimi
,
M. S.
,
2006
, “
LES Benchmark Study of High Cycle Temperature Fluctuations Caused by Thermal Striping in a Mixing Tee
,”
Int. J. Heat Fluid Flow
,
27
, pp.
54
64
.10.1016/j.ijheatfluidflow.2005.08.001
10.
Hosseini
,
S. M.
,
Yuki
,
K.
, and
Hashizume
,
H.
,
2008
, “
Classification of Turbulent Jets in a T-Junction Area With a 90-deg Bend Upstream
,”
Int. J. Heat Mass Transfer
,
51
, pp.
2444
2454
.10.1016/j.ijheatmasstransfer.2007.08.024
11.
Oka
,
K.
, and
Ito
,
H.
,
2005
, “
Energy Loss at Tees With Large Area Ratios
,” Trans.
ASME J. Fluids Eng.
,
127
(1), pp.
110
116
.10.1115/1.1852475
12.
De Chant
,
L. J.
,
2005
, “
The Venerable 1/7th Power Law Turbulent Velocity Profile: A Classical Nonlinear Boundary Value Problem Solution and Its Relationship to Stochastic Processes
,”
Appl. Math. Comput.
,
161
(
2
), pp.
463
474
.10.1016/j.amc.2003.12.109
13.
Qian
,
S.
, and
Kasahara
,
N.
,
2011
, “
LES Analysis of Temperature Fluctuations at T-Junctions for Prediction of Thermal Loading
,”
ASME
Paper No. PVP2011-57292.10.1115/PVP2011-57292
You do not currently have access to this content.