A Study on Cavitation Erosion Behavior of Different Metals in Biomass Fuel/Diesel Blend

2. Experimental Procedures

Figure 1 shows that schematics of the ultrasonic vibration cavitation erosion apparatus. The vibration horn performs an axial vibration with the frequency of 20kHz and the amplitude of 60μm. Cavitation tests were carried out in emulsified biomass fuel/diesel with different components. Since the test liquid temperature markedly affects the degree of erosion and impact pressure (Ahmed, 1997), the temperature was kept within 25±2°C by circulating cooling water around the beaker.

Figure 1.

Schematics of the cavitation experimental apparatus (1. water inlet, 2. cooling water, 3. container wall, 4. transducer, 5. vibratory horn and sample, 6. breaker, 7. water outlet, 8. ultrasonic generator)

GCr15 is one kind of nozzle materials with the process of spheroidization annealing. The sample was designed according to the ASTM standard of the vibration cavitation erosion system (ASTM, 1995); the working surfaces were polished by 800# emery paper. What was more, in order to fix the sample in the vibration horn, the back-end of samples was processed into thread shapes. As reference metals, the pure copper and stainless steel 1Cr18Ni9Ti were selected and prepared to compare their cavitation erosion performances with GCr15. Their pretreatment procedures were the same with those of GCR15 before cavitation tests. The chemical compositions of test metal samples were shown in Table 1.