An experimental investigation into the pressure - leakage relationship of some failed water pipes

Abstract

This paper reports on an experimental study that was conducted to measure the leakage exponents of different types of leak openings (holes, corrosion holes, and longitudinal and circumferential cracks) and pipe materials (asbestos cement, mild steel and uPVC). A number of failed pipes taken from the Johannesburg water distribution system were tested, as well as a number of pipes with artificially induced leaks. The results of the study confirmed that leakage exponents can be significantly higher than the theoretical value of 0.5. While leakage exponents for round holes were close to 0.5, the values for corrosion holes varied between 0.67 and 2.30, for longitudinal cracks between 0.79 and 1.85, and for circumferential cracks between 0.41 and 0.52. Conclusions include that the highest leakage exponents were found in corroded steel pipes and that under certain circumstances, leakage exponents can be less than 0.5.

Leakages and pressure relation: an experimental research

“…For example, for steel pipes with holes caused by corrosion, the coefficients b identified experimentally (Greyvenstein and van Zyl, 2006) for the pipes 4, 5 and 6 shown in Fig. 8 are, respectively, 0.67, 1.96 and 2.3; for an undamaged pipe, with the same mechanical properties, with an artificial hole diameter of 12 mm, the identified coefficient is equal to 0.518.…”

“…Probably they are due to a reduced consistence of material around the holes (due to corrosion) (Greyvenstein and Van Zyl, 2006) or to the remarkable flexibility of plastic pipes (Farley and Trow, 2003;Walski et al, 2006;Ferrante et al, 2010;Bovolin and Picciotti, 2008).…”

“…The present work gives a global summary of all the experimental tests conducted so far. In particular, results of the dynamic tests performed on steel and ductile iron pipes are presented, and compared to the other ones present in literature (Sendil and Al Dhowalia, 1992;Lambert, 2000;Thornton and Lambert, 2005;Greyvenstein and Van Zyl, 2006;Milano, 2006;Coetzer et al, 2006;Ferrante et al, 2010;Massari et al, 2012).…”

A decision support system for on-line leakage localization

“…In these cases, the dependence of leaks on pressure (Greyvenstein, 2007;Lambert, 1997) is the keystone in the detection, localisation and control.…”

Improving leakage management in urban water distribution networks through data analytics and hydraulic simulation

“…The flow rate through the emitter varies according to the pressure according to the function q = C p γ , where q is the flow rate, p is the pressure, C is the discharge coefficient and γ is the pressure exponent. The pressure coefficient depends on geometry of the orifice (Greyvnstein and Van Zyl [26]) and material of the pipelines (Van Zyl and Clayton [27]) and its typical value is 0.5 for circular orifices.…”