Failure Analysis of Pipe System at a Hydroelectric Power Plant
In this study, failure analysis of pipe system at a micro
hydroelectric power plant is investigated. Failure occurred at the pipe
system in the powerhouse during shut down operation of the water
flow by a valve. This locking had caused a sudden shock wave, also
called “Water-hammer effect”, resulting in noise and inside pressure
increase. After visual investigation of the effect of the shock wave on
the system, a circumference crack was observed at the pipe flange
weld region. To establish the reason for crack formation, calculations
of pressure and stress values at pipe, flange and welding seams were
carried out and concluded that safety factor was high (2.2), indicating
that no faulty design existed. By further analysis, pipe system and
hydroelectric power plant was examined. After observations it is
determined that the plant did not include a ventilation nozzle (air
trap), that prevents the system of sudden pressure increase inside the
pipes which is caused by water-hammer effect. Analyses were carried
out to identify the influence of water-hammer effect on inside
pressure increase and it was concluded that, according Jowkowsky’s
equation, shut down time is effective on inside pressure increase. The
valve closing time was uncertain but by a shut down time of even one
minute, inside pressure would increase by 7.6 bar (working pressure
was 34.6 bar). Detailed investigations were also carried out on the
assembly of the pipe-flange system by considering technical
drawings. It was concluded that the pipe-flange system was not
installed according to the instructions. Two of five weld seams were
not applied and one weld was carried out faulty. This incorrect and
inadequate weld seams resulted in; insufficient connection of the pipe
to the flange constituting a strong notch effect at weld seam regions,
increase in stress values and the decrease of strength and safety
factor.
[1] V. Vineesh V, and A. I. Selvakumar, “Design of Micro Hydel Power
Plant,” International Journal of Engineering and Advanced Technology,
vol. 2, 2012, pp. 136-140.
[2] B.A. Nasir, “Design of Micro - Hydro - Electric Power Station,”
International Journal of Engineering and Advanced Technology, vol. 2,
2013, pp. 39-47.
[3] H. Sharma, and J. Singh, “Run off River Plant: Status and Prospects,”
International Journal of Innovative Technology and Exploring
Engineering, 2278-3075, vol. 3, 2013, pp. 2278-3075.
[4] M. Çalamak, and Z. Bozkus, “Protective Measures against
Waterhammer in Run-of-River Hydropower Plants,” Digest, vol.12,
2012, pp. 1623-1636.
[5] T.W. Choon, L.K. Aik, L.E. Aik, and T. T. Hin, “Investigation of Water
Hammer Effect through Pipeline System,” International Journal on
Advance Science Engineering Information Technology, vol. 7, 2012 pp.
48-53.
[6] S. Dursun, and Z. Bozkus, “Numerical Investigation of Protection
Measures Against Water Hammer in the Yesilvadi Hydropower Plant,”
11th International Congress on Advances in Civil Engineering, Istanbul
2014.
[7] J. Wood, “Waterhammer Analysis—Essential and Easy „and Efficient”
Journal of Environmental Engineering, vol. 8, 2005, pp. 1123-1131.
[8] A. Leishear, Fluid Mechanics, Water Hammer, Dynamic Stresses, and
Piping Design, ASME, New York, 2012.
[9] A. Dudlik, S.B. Handajani, Schönfeld, S. Schlüter, H. Fahlenkamp, and
H.M. Prasse, “Prevention of Water Hammer and Cavitational Hammer
in Pipeline Systems,” Chemical Engineering & Technology, vol. 09,
2002; pp. 888-890.
[10] K. Paffel,” The number One Problem in a Steam System:
Waterhammer,” Chemical Engineering, vol. 4, 2008, pp. 1-4.
[11] G. Gjetvaj, and M. Tadic, “The Effect of Water Hammer on Pressure
Increase in Pipelines Protected by an Air Vessel,” Technical Gazette,
vol. 21, 2014, pp. 479-484.
[12] S. Mohamed, M. Ghidaoui, Z. Duncan, and H. Axworthy, “A Review of
Water Hammer Theory and Practice,” Applied Mechanics Reviews, vol.
58, 2005, pp. 49-76.
[1] V. Vineesh V, and A. I. Selvakumar, “Design of Micro Hydel Power
Plant,” International Journal of Engineering and Advanced Technology,
vol. 2, 2012, pp. 136-140.
[2] B.A. Nasir, “Design of Micro - Hydro - Electric Power Station,”
International Journal of Engineering and Advanced Technology, vol. 2,
2013, pp. 39-47.
[3] H. Sharma, and J. Singh, “Run off River Plant: Status and Prospects,”
International Journal of Innovative Technology and Exploring
Engineering, 2278-3075, vol. 3, 2013, pp. 2278-3075.
[4] M. Çalamak, and Z. Bozkus, “Protective Measures against
Waterhammer in Run-of-River Hydropower Plants,” Digest, vol.12,
2012, pp. 1623-1636.
[5] T.W. Choon, L.K. Aik, L.E. Aik, and T. T. Hin, “Investigation of Water
Hammer Effect through Pipeline System,” International Journal on
Advance Science Engineering Information Technology, vol. 7, 2012 pp.
48-53.
[6] S. Dursun, and Z. Bozkus, “Numerical Investigation of Protection
Measures Against Water Hammer in the Yesilvadi Hydropower Plant,”
11th International Congress on Advances in Civil Engineering, Istanbul
2014.
[7] J. Wood, “Waterhammer Analysis—Essential and Easy „and Efficient”
Journal of Environmental Engineering, vol. 8, 2005, pp. 1123-1131.
[8] A. Leishear, Fluid Mechanics, Water Hammer, Dynamic Stresses, and
Piping Design, ASME, New York, 2012.
[9] A. Dudlik, S.B. Handajani, Schönfeld, S. Schlüter, H. Fahlenkamp, and
H.M. Prasse, “Prevention of Water Hammer and Cavitational Hammer
in Pipeline Systems,” Chemical Engineering & Technology, vol. 09,
2002; pp. 888-890.
[10] K. Paffel,” The number One Problem in a Steam System:
Waterhammer,” Chemical Engineering, vol. 4, 2008, pp. 1-4.
[11] G. Gjetvaj, and M. Tadic, “The Effect of Water Hammer on Pressure
Increase in Pipelines Protected by an Air Vessel,” Technical Gazette,
vol. 21, 2014, pp. 479-484.
[12] S. Mohamed, M. Ghidaoui, Z. Duncan, and H. Axworthy, “A Review of
Water Hammer Theory and Practice,” Applied Mechanics Reviews, vol.
58, 2005, pp. 49-76.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:70925", author = "Ali Göksenli and Barlas Eryürek", title = "Failure Analysis of Pipe System at a Hydroelectric Power Plant", abstract = "In this study, failure analysis of pipe system at a micro
hydroelectric power plant is investigated. Failure occurred at the pipe
system in the powerhouse during shut down operation of the water
flow by a valve. This locking had caused a sudden shock wave, also
called “Water-hammer effect”, resulting in noise and inside pressure
increase. After visual investigation of the effect of the shock wave on
the system, a circumference crack was observed at the pipe flange
weld region. To establish the reason for crack formation, calculations
of pressure and stress values at pipe, flange and welding seams were
carried out and concluded that safety factor was high (2.2), indicating
that no faulty design existed. By further analysis, pipe system and
hydroelectric power plant was examined. After observations it is
determined that the plant did not include a ventilation nozzle (air
trap), that prevents the system of sudden pressure increase inside the
pipes which is caused by water-hammer effect. Analyses were carried
out to identify the influence of water-hammer effect on inside
pressure increase and it was concluded that, according Jowkowsky’s
equation, shut down time is effective on inside pressure increase. The
valve closing time was uncertain but by a shut down time of even one
minute, inside pressure would increase by 7.6 bar (working pressure
was 34.6 bar). Detailed investigations were also carried out on the
assembly of the pipe-flange system by considering technical
drawings. It was concluded that the pipe-flange system was not
installed according to the instructions. Two of five weld seams were
not applied and one weld was carried out faulty. This incorrect and
inadequate weld seams resulted in; insufficient connection of the pipe
to the flange constituting a strong notch effect at weld seam regions,
increase in stress values and the decrease of strength and safety
factor.", keywords = "Failure analysis, hydroelectric plant, water-hammer,
crack, welding seam.", volume = "9", number = "9", pages = "1643-4", }