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Tham khảo tài liệu 'hydroblasting and coating of steel structures episode 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 168 Hydroblasting and Coating of Steel Structures Table 7.2 Cleaning capability of self-resonating jets Chahine et al. 1983 Parameter Conventional jet Self-resonating jet Operating pressure in MPa 3.1 3.1 Cleaning width in mm 25 51 Cleaning rate in m2 h 56 111 Specific energy in m2 kWh 19.8 27.5 Table 7.3 Ship hull cleaning with a self-resonating water jet SERVOJET results Conn and Chahine 1983 . Nozzle type Surface quality Operating pressure in MPa Typical cleaning rate in m2 h Typical specific cleaning energy in m2 kWh Circular orifice. Sa 1 48.2 16.7-29.7 0.12-0.19 diameter 1.1 mm Sa 1 55.1 20.8-21.9 0.15-0.16 Sa 1 62.0 14.8 0.11 Sa 2 48.2 8.5-18.6 0.06-0.12 Sa 2 55.1 6.6-13.3 0.05-0.10 Sa 2 62.0 5.3 0.04 Fan 15 nozzle Sa 1 48.2 10.3-21.5 0.09-0.17 equivalent Sa 1 62.0 21.5 0.20 diameter 0.9 mm Sa 2 48.2 4.2-7.5 0.04-0.06 Sa 2 62.9 1.0 0.01 5 10 10 20 30 40 Stand-off distance in cm Figure 7.11 Comparative paint removal results Chahine et al. 1983 . dynamic component natural pulsation due to drop formation if a certain jet length is reached see Fig. 2.3 . The corresponding loading regime is comparable to that generated by the self-resonating jet. Therefore the removal efficiency of the conventional jet approaches that of the discontinuous jet. However at small standoff distances self-resonating jets perform much more effectively. Alternative Developments in Hydroblasting 169 7.2 Hydro-Abrasive Jets for Surface Preparation 7.2.1 Types and Formation of Hydro-Abrasive Jets A comprehensive review of hydro-abrasive jets is given by Momber and Kovacevic 1998 . From the point of view of jet generation the following two types hydroabrasive jets can be distinguished injection jets suspension jets. A hydro-abrasive injection jet is formed by accelerating small solid particles garnet aluminium oxide silica carbide through contact with one or more high-speed water jets. The high-speed waterjets are formed in orifices placed on top of the mixing-and-acceleration head. The .