| People pay more and more attention to high performance water jet.For example, various additives were added into jet that can improve thecapacity of cutting and erosion. Taking pulsed water-gas nozzles asresearch object, based on self-excited oscillation pulsed jet, the pulsedwater-gas jet has been formed by entraining and mixing the air in theself-oscillating pulsed jet that can improve the affect of oscillation and thecapacity of rock breaking. Mathematics model of disturbance wavepropagation in oscillation chamber was established by using continuityequation and momentum equation. The cantilever beam was adopted aserosion object.QLVC-ZSA1Vibration Analyzer was used to test vibrationof the cantilever beam which was impacted by the pulsed water-gas jet,and dynamic characteristics of pulsed water-gas jet is obtained. Comparedwith pulsed jet, the frequency characteristic of pulsed water-air jetbecomes more complicated, and the main pulsed frequency move to theleft. By analyzing the spectrum graph, the variation rule of frequencyversus the pump pressure or cavity length can be obtained. In addition, theerosion performance of pulsed water-air jet and pulsed jet were verified bythe use of concrete, the compressive strength of which is6.9MPa. Theresults indicated that the erosive effect of pulsed water-air jet is superior tothat of the pulsed jet, the maximal erosive volume of the former issignificantly higher than that of latter (22%), but the erosion depthbetween them shows little change. The erosive volume of the pulsedwater-air jet increase with the volumetric flux of the injected air,eventually reaching a maximum value, and then decreasing slightly,namely there exists an optimum air-flow rate. However, the air flow ratehas slight effect on the erosion depth. |
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