212.Nozzle Load Stress Analysis Using WRC 107 and WRC 297

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ISSN 2395-1621

International Engineering Research Journal (IERJ) Special Issue 2 Page 1191-1194, 2015, ISSN 2395-1621

Nozzle Load Stress Analysis Analysis using WRC 107 and WRC 297 #1

G.S. Jagadale, #2M.S. Ramgir 1

jagadalegs1987@g [email protected] mail.com 2

[email protected]

# 12

Mechanical Engineering Department, Pune University Rajarshi Shahu College of Engineering, Tathawade, Pune, India.

ABSTRACT

ARTICLE INFO

Pressure vessels are closed containers used for storing, receiving or carrying the fluids. Nozzles are welded on shell, dished end (circular and spherical surfaces) or on flat surfaces. These nozzles carrying fluid, provide mounting of equipment such as motors, agitators, incoming piping, exposed to wind and seismic activity. Due to this, nozzles are subjected to different loadings in x, y, z directions and six degrees of the moment. This results in failure and stress generation at the weld joints at the junction of nozzle and shell. Nozzle loading analysis at the junction of the vessel is available at WRC 107 and WRC 297 when surfaces are cylindrical and spherical with circular openings. In the present work, nozzle loading analysis at the junction of the vessel is examined for the circular opening on the flat surface of the vessel. WRC 107 analyzes only circular opening on the cylindrical surface of the vessel so as the PVELITE software. In the present case, there is a circular opening on the flat surface of the vessel, unable to analyze in PVELITE software. To conquer this inadequacy, analysis is carried out by both WRC 107 and PVELITE software considering radius of the cylinder as maximum as possible so that area of cylinder assumed to be almost flat. This paper focuses on the verifying the effects of nozzle loadings on stress attributes of the vessel. Theoretical calculations are validated with experimental analysis. It is found that the the oretical and experimental results are closer to each other. Keywords — Nozzle, Pressure Vessel, PVELITE, WRC .

Article History

I.INTRODUCTION Pressure vessels are the closed containers used for storing, receiving or carrying the fluids [1]. Nozzles are welded on the shell, dished end (circular and spherical surfaces) or on flat surfaces These nozzle functions of carrying fluid, provide mounting of equipment such as motors, agitators, incoming piping, exposed to wind and seismic activity. Due to this, nozzles are subjected to different loadings in x, y and z directions and six degrees of the moment. This results in stress generation and failure at the weld joints at the junction of nozzle and shell. Narale Pravin and Kachare, P. S. [2] analyzed the effects of nozzle on Stress attributes of the vessel in FEA Hardik B. Nayak and R. R. Trivedi [3] give a more accurate stress evaluation of nozzle to head junction using FE analysis than WRC 107. Anindya Bhattacharya [4] highlighted the strengths and weaknesses of the conventionally used methods such

© 2015, IERJ All Rights Reserved

Received 2015

th

:18

November

Received in revised form : 19th November 2015 Accepted : 21 st November , 2015 Published online : nd

22 November 2015

as FEA, WRC 107 and WRC 297. Fang, J. [5] et. al focused that the pad reinforcement structures are useful under static external load on nozzle. Magnucki, K. [6] et. al investigated on flexible saddle support of a horizontal cylindrical pressure vessel using parametric models. Kharat Avinash and Kulkarni, V. V. [7] reviewed out work on the stress concentration at openings in pressure vessels. A.

WRC 107 WRC 107 AND WRC 297 AND WRC 297

Welding Research Council‘s Bulletins, WRC 107 and WRC 297 provide most important guidelines for the weld

joint analysis due to the loadings. It gives methods and data for treating two normally intersecting cylindrical shells [8,9]. Nozzle loading analysis is also available in PVELITE

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software when only the surfaces are cylindrical and spherical with circular openings as shown in Fig. 1.

Fig. 1. Loading conditions at an attachment to cylindrical shell [8,9]

WRC 107 to perform nozzle loading analysis with circular opening on the flat surface. To conquer this inadequacy, supplement formulae are attempted for calculating the stresses at the junction and experimental validation is carried out.

Fig. 2. Drawing of user specified nozzle loading condition

Fig. 2 shows the nozzle loading conditions specified by the user to determine the stresses at the weld joints. In present work there is a circular opening on the flat surface of the vessel. PVELITE software has the same limitation of II.SOFTWARE ANALYSIS

For nozzle loading analysis, design data and nozzle input loadings are described as shown in the tables I and II. TABLE I DESIGN DATA Sr. No . 1 2 3 4 5 6 7 8

Description

Values

Design Pressure Design Temperature Material of Shell Material of Nozzle Allowable stress for Shell Allowable stress for Nozzle Vessel Inside Diameter (D) Nozzle Inside Diameter (d)

5 Kgf/cm2 80 °c SA516GR 70 SA106 GR.B 2 1406.1 Kgf/cm 1202.25 Kgf/cm2 600 mm

Fig. 3. WRC 107 calculations for nozzle on flat head Therefore an attempt is made by considering the circular surface and increasing maximum radius from R= 4 m to R=12 m so that the nozzle will remain on circular surface, but the opening of 100 NB will become almost flat as shown in Fig. 4.

100 mm

TABLE III I NPUT NOZZLES LOADING Nozzle Loads Value

FX, N

FY, N

FZ, N

1000

1000

1000

MX, N-m 1000

MY, N-m 1000

MZ, N-m 1000

Fig. 3. shows that the PVELITE software is unable to perform WRC 107 analysis when nozzle is located on a flat surface showing incorrect element type, local stress analysis not possible. Fig. 4. Comparison of circular and flat surface


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Using PVELITE software, membrane (Pm), bending (Pm+Pl) and total stresses (Pm+Pl+Q) are calculated at radius R=4 m to R=12 m as tabulated in the tables III, IV, V respectively. TABLE IIIII

Type of Stress Pm (SUS) Pm+Pl (SUS) Pm+Pl+Q (Total)

Maximum Stress (kgf/cm²) 775.03 774.41

Allowable Stress (kgf/cm²) 1406.14 2109.21

Passed Passed

825.02

4218.42

Passed

Result

STRESS I NTENSITY AT R= 4 M Type of Stress Pm (SUS) Pm+Pl (SUS) Pm+Pl+Q (Total)



Passed Passed

660.97

4218.42

Passed

TABLE V Result

TABLE IV

STRESS I NTENSITY AT R= 12 M Type of Stress Pm (SUS) Pm+Pl (SUS) Pm+Pl+Q (Total)



Passed Passed

949.25

4218.42

Passed

Result

STRESS I NTENSITY AT R= 8 M

III.THEORETICAL CALCULATIONS

During the theoretical calculations, all the applied loads and moments are resolved in x, y and z direction. It consists of resolved components P, V L, VC, ML, MC and MT to find membrane, bending and total stresses at the junction. All the nozzle loads and moments are supposed to act at the same time. For manual calculations, WRC 107 assumes λ=0.01 to analyze the circular openi ng on the flat surface of the vessel so the area of the cylinder becomes almost flat. The longitudinal and transverse stresses are calculated and tabulated as shown in Table VI.

LONGITUDINAL AND TRANSVERSE STRESS USING WRC 107 Type of stress Pm (SUS) Pm+Pl (SUS) Pm+Pl+Q (Total)

Longitudinal Stress (kgf/cm²) Actual Allowable

Transverse Stress (kgf/cm²) Actual Allowable

0.19

2109.15

0.34

2109.15

0.18

2109.15

0.33

2109.15

0.53

4218.3

0.51

4218.3

TABLE VI IV.EXPERIMENTAL ANALYSIS

An overall view of the experimental set-up is presented in Fig. 5. A pipe of NB 100 mm and 150 mm length is welded to the flat surface of a vessel to form the nozzle. In order to apply various dead weights on the nozzle, a rectangular frame with pulleys is welded to the top of the vessel as shown in Fig. 5.

directions. Six strain gauges are pasted at the nozzle vessel junction. Three of them are pasted at various positions in such a way to acquire strains developed in x, y and z directions. Set of strain gauges is attached to form node one and node two at two different locations. Nozzle inlet is connected to the hydro test rig to develop the internal pressure from 0 - 5 kgf/cm². A pressure gauge indicator is installed to monitor the gauge pressure. The strain gauges are connected to the strain gauge indicator. Strain values are recorded by changing load, internal pressure and probe combination. Considering the plane stress conditions, the longitudinal and transverse stresses at the junction are calculated and tabulated as shown in Table VII. TABLE VII LONGITUDINAL AND TRANSVERSE STRESSES FROM EXPERIMENTAL ANALYSIS

Type of stress

Fig. 5. Experimental set up

Stress Intensity (kgf/cm²)

Longitudinal stress

Transverse stress

0.1635

0.0687

The arrangement of the frame along with the pulleys is assembled such that the loads applied are in x, y and z


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V.R ESULTS AND CONCLUSION

The stress intensity at the junction of the vessel and nozzle is determined by manual calculation and validated with its experimental analysis as tabulated in Table VIII. REFERENCES

[1] M. Pradeep Kumar, K. Vanisree, Sindhuja Raj, ―Design and Implementation of circular cross sectional pressure vessel using Pro-e and Ansys‖, ISSN: 22496645, Vol. 3, Issue 4, pp. 23502355, Jul - Aug. 2013.

[2]

Narale Pravin, Kachare, P. S., ―Structural Analysis of Nozzle Attachment on Pressure Vessel Design‖, International Journal of Engineering Research and Applications (IJERA), ISSN: 2248-9622, Vol. 2, Issue4, pp. 1353-1358, July-August 2012.

[3]

Nayak, Hardik B., and Trivedi, R. R., ―Spherical and cylindrical shell due to external loading in the stress Analysis of Reactor Nozzle to Head Junction‖, International Conference on Current Trends in Technology, 2 ‗NUiCONE – 2011‘, Institute of Technology, Nirma University, Ahmadabad – 382481, 08-10, December 2011.

[4] Bhattacharya Anindya, ―Stress Analysis of Pipe Support Attachments: A Comparison of analytical Methods and Finite Element Analysis of Circular and NonCircular Attachments‖, Proc. of the ASME 2013 Pressure Vessels & Piping Division Conference, PVP 2013, July 14-18, 2013, Paris, France, pp. 1-17.

212.Nozzle Load Stress Analysis Using WRC 107 and WRC 297

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