0
Research Papers: Fluid-Structure Interaction

Classification of Flow Patterns in Angled T-Junctions for the Evaluation of High Cycle Thermal Fatigue

[+] Author and Article Information
Shaoxiang Qian

Mem. ASME
EN Technology Center,
Engineering Division,
JGC Corporation,
2-3-1 Minato Mirai,
Nishi-ku, Yokohama 220-6001, Japan
e-mail: qian.shaoxiang@jgc.com

James Frith

Mem. ASME
EN Technology Center,
Engineering Division,
JGC Corporation,
2-3-1 Minato Mirai,
Nishi-ku, Yokohama 220-6001, Japan
e-mail: frith.james@jgc.com

Naoto Kasahara

Nuclear Engineering and Management,
School of Engineering,
The University of Tokyo,
7-3-1 Hongo,
Bunkyo-ku, Tokyo 113-8656, Japan
e-mail: kasahara@n.t.u-tokyo.ac.jp

1Corresponding author.

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNAL OF PRESSURE VESSEL TECHNOLOGY. Manuscript received December 19, 2013; final manuscript received June 22, 2014; published online October 15, 2014. Assoc. Editor: Jong Chull Jo.

J. Pressure Vessel Technol 137(2), 021301 (Oct 15, 2014) (7 pages) Paper No: PVT-13-1215; doi: 10.1115/1.4027903 History: Received December 19, 2013; Revised June 22, 2014

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Illustration for investigation into the interacting mechanism of momentum between main and branch pipes for T-junctions

Grahic Jump Location
Fig. 2

Illustration accounting for the definition of momentum ratio for Y-junctions

Grahic Jump Location
Fig. 3

Computational models of the tee junctions

Grahic Jump Location
Fig. 10

Fluid temperature distribution and velocity vectors for MR = 0.33

Grahic Jump Location
Fig. 9

Fluid temperature distribution and velocity vectors for MR = 0.38

Grahic Jump Location
Fig. 8

Fluid temperature distribution and velocity vectors for MR = 1.25

Grahic Jump Location
Fig. 7

Fluid temperature distribution and velocity vectors for MR = 1.45

Grahic Jump Location
Fig. 6

Fluid temperature distribution and velocity vectors for MR = 3.80

Grahic Jump Location
Fig. 5

Fluid temperature distribution and velocity vectors for MR = 4.20

Grahic Jump Location
Fig. 14

Comparison of normalized time-averaged axial velocity and fluid temperature distributions along the vertical direction at the location of X = 0.5Dm for mesh sensitivity investigation

Grahic Jump Location
Fig. 4

Meshes for the computational models

Grahic Jump Location
Fig. 12

Comparison of normalized time-averaged axial velocity and fluid temperature distributions along the vertical direction at the location of X = 0.5Dm for validation of CFD prediction by RKE turbulence model

Grahic Jump Location
Fig. 13

Location and direction (arrowed pink lines) for the plots in Figs. 12 and 14

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In