高压密相流体中超声空化现象的研究

利用空化测试材料研究了超声在高压密相流体CO2中的空化效应,并从理论上进行了分析。实验发现在相同功率的超声作用下,空化测试材料在高压液体CO2中能产生明显的空洞,但在超临界CO2无空洞产生,说明超声能在高压液体CO2(亚临界)产生超声空化现象,而不能在超临界CO2中产生空化现象。理论分析表明,当CO2处于高压液体状态时,由于CO2具有很高的蒸汽压,抵消了外界的高压,因此超声能够产生空化效应;而当CO2处于超临界状态时,由于体系不存在汽-液界面,因此阻碍了空化现象的产生。

Ultrasonic cavitation in high-pressure and dense-phase fluids

With the cavitation test material,ultrasonic cavitation in high-pressure and dense-phase fluids was explored and the theoretic deduction was probed.According to the experimental results,at the same power of ultrasound,the cavitation test material shows many pores in high-pressure liquid CO2,whereas,it did not appears in supercritical CO2.This phenomena shows that ultrasound can generate cavitation in high-pressure liquid CO2(subcritical station),but not in supercritical CO2.Based on theoretic deduction,ultrasound can generate cavitation in high-pressure liquid CO2 due to high vapor pressure of CO2,reduced the external pressure influence.However,there are no liquid-gas phase boundaries in the supercritical CO2,hence prohibiting cavitation.