24 1机组3HRCW51 1#机组3#RCW5181 1#机组3#RCW54-77 2006519 Figure 9. External appearances of the ruptures on leaked tubes clogged by rubber debris: (a) ruptures and crack, (b)rolled rubber debris,(c) all, (d) sediment, seashell, and rubber debris. As for the former one once erated on the outside wall of the which was frequently observed in the Part L. As a consequence, erosion effect would be exerted on the bulge by the natural seawater containing sediment particles, quickly thinning its wall thickness, and finally lead to a rupture. Once the rupture w formed, a small amount of seawater would flow through it and simultaneously induce erosion effect on its fringes too, gradually enlarging its size, and would sometimes even create an oriented (see Part I). In terms of th one, the following paragraphs will discuss the different erosion effects on the tubes when being clogged by, respectively, sediment, seashell, and rubber debris. In fact, the erosion effect on the tube when clogged by sediment was not so serious, only two consequences will be Figure 10. External appearance of the rupture evolved from brought about. The first one was still the erosion effect but in mechanical damage on tube outside wall severer extent Our past works[ 12-14] verified this fact. In detail, according to Equation(2), in which Q was the volume flow quantity, u was the fluid velocity, i was the average fluid velocity, and a was the cross-sectional area of the tube, in order to keep aggravated by other defects on the tubes in advance. Summariz. the consistence of the flow, i.e., Q remains constant, i will be g the results in both the Part I and the Part Il, two main kinds of certainly increased if a was reduced due to partly clogging of defects should be ascribed to- the electrochemical corrosions the tube by sediment. Then, it is a common sense that the faster pecially hydrogen blistering, and the clogging primarily by the fluid velocity is, the severer the erosion effect will be on the o 2012 WILEY-VCH Verlag Gmbh Co KGaA, Weinheim www.matcorr.comaggravated by other defects on the tubes in advance. Summariz￾ing the results in both the Part I and the Part II, two main kinds of defects should be ascribed to – the electrochemical corrosions especially hydrogen blistering, and the clogging primarily by sediment, seashell, and rubber debris. As for the former one, once hydrogen blistering was generated on the outside wall of the tube, the tube wall was localizedly bulged inwards the inside wall, which was frequently observed in the Part I. As a consequence, erosion effect would be exerted on the bulge by the natural seawater containing sediment particles, quickly thinning its wall thickness, and finally lead to a rupture. Once the rupture was formed, a small amount of seawater would flow through it and simultaneously induce erosion effect on its fringes too, gradually enlarging its size, and would sometimes even create an oriented eddy erosion effect on its corner (see Part I). In terms of the latter one, the following paragraphs will discuss the different erosion effects on the tubes when being clogged by, respectively, sediment, seashell, and rubber debris. In fact, the erosion effect on the tube when clogged by sediment was not so serious, only two consequences will be brought about. The first one was still the erosion effect but in severer extent. Our past works [12–14] verified this fact. In detail, according to Equation (2), in which Q was the volume flow quantity, u was the fluid velocity, u was the average fluid velocity, and A was the cross-sectional area of the tube, in order to keep the consistence of the flow, i.e., Q remains constant, u will be certainly increased if A was reduced due to partly clogging of the tube by sediment. Then, it is a common sense that the faster the fluid velocity is, the severer the erosion effect will be on the 24 Gong, Yang and Yuan Materials and Corrosion 2012, 63, No. 1 Figure 9. External appearances of the ruptures on leaked tubes clogged by rubber debris: (a) ruptures and crack, (b) rolled rubber debris, (c) crimples on tube inside wall, (d) long indentations on tube inside wall Figure 10. External appearance of the rupture evolved from a mechanical damage on tube outside wall
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