ABSTRACT
It is generally agreed that abrasive wear increases rapidly with flow, or particle, velocity and, as indicated in section 2.3, many authors suggest a simple power law relationship for both pump and pipe wear, based either on laboratory wear tests or theoretical considerations. For pump wear, it is most often quoted that wear rate is approximately proportional to (velocity) 3 or proportional to (pump head) 312 ; some authors (e.g. 5,51) suggest a range of index from 2.2-3. The German sandblast simulation tests (21) indicated that it may depend on the material; e.g. for steel, the index was 1.4 and for rubber, 4.6 for direct impact wear. De Bree's later simulation tests (25) gave a variation in index from 2.9-3.7 for two steels, depending on the type and also particle size (see Figure 4); low-carbon steel was more sensitive to speed variation than the harder 15/3 Cr Mo steel. Other authors suggest that there may be differences between ductile and brittle materials (4), or that there may be some critical value of velocity, below which wear increases, say linearly, but above which the increase is much more rapid. Results from the only pump wear test to investigate the effect of speed, noted by Truscott (4), agreed with the cubic exponent of velocity relationship for wear.
