Abstract:A series of experiments on underwater self-excited pulse jet are made by using a self-developed test platform and the axial and radial distributions of pressure around an underwater self-excited pulse jet are obtained. Then, the flow fields inside and outside the jet are simulated, the corresponding velocity and pressure distributions are acquired and compared with the experimental data. The results show that obvious low frequency pulses can occur for the self-excited pulse jet under non-submerged condition. Under submerged condition, however, because part of the jet energy is consumed in the submerged water body so much that it is hard for cavitation to form in the chamber and to generate obvious pulse, further the stagnation pressure is reduced significantly. The radial pressure distribution is basically the same in different depths of the water, approximately yields the Gaussian distribution. The axial stagnation pressure is decreased with the increasing distance to the target, and its attenuation characteristic is similar to that for continuous jet and under non-submerged condition, just the decay rate is even faster. A low pressure zone in the jet core, two symmetrical negative pressure zones and a high pressure impinging zone exist in the flow field in the chamber of the underwater self-excited pulse jet device. Vortexes are generated near the bottom casing, and the flow field is similar to the jet flow in the chamber, but without a core.
[1]李国英.基于水库群联合调度和人工扰动的黄河调水调沙[J].水利学报,2006,37(12):1439-1446. LI Guoying. Regulation of water and sediment for the Yellow River based on joint operation of reservoirs and artificial intervention[J].Journal of hydraulic enginee-ring,2006, 37(12): 1439-1446.(in Chinese)[2]唐川林,廖振方.自激振动脉冲射流装置的理论分析和实验研究[J].煤炭学报,1989,14(1):90-100. TANG Chuanlin, LIAO Zhenfang. Theoretical analysis and experimental study a self-excited oscillation pulsed jet device[J].Journal of China coal society,1989,14(1):90-100.(in Chinese)[3]高传昌,赵礼,刘新阳,等.淹没条件下自激脉冲射流冲蚀试验研究[J].排灌机械工程学报,2012, 30(1): 53-56. GAO Chuanchang, ZHAO Li, LIU Xinyang, et al. Experiment research on erosion of self-excited inspired pulsatile jet in submerged conditions[J]. Journal of drai-nage and irrigation machinery engineering, 2012, 30(1):53-56.(in Chinese)[4]高传昌,苏泊源,张世斌,等.深水自激吸气脉冲射流装置冲蚀性能试验[J].江苏大学学报:自然科学版, 2014, 35(2): 160-164. GAO Chuanchang,SU Boyuan,ZHANG Shibin, et al. Erosion performance of self-excited inspiration pulse jet device in deep water[J]. Journal of Jiangsu University(natural science edition),2014,35(2):160-164.(in Chinese)[5]SONG X Z, LI G S,YUAN J P, et al. Mechanisms and field test of solution mining by self-resonating cavitating water jets[J]. Pet Sci, 2010, 7(3):385-389.[6]ANNONI M, ARLEO F, MALMASSARI C. CFD aided design and experimental validation of an innovative air assisted pure water jet cutting system[J]. Journal of mater process Technology, 2014, 214: 1647-1657.[7]王循明,王乐勤,焦磊.自激脉冲射流喷嘴参数对装置能耗影响分析[J].工程热物理学报,2008,29(5);780-782. WANG Xunming, WANG Leqin, JIAO Lei. The energy loss analysis of the self-excited oscillation pulsed jet with parameters change[J]. Journal of engineering thermophysics, 2008, 29(5):780-782.(in Chinese)[8]王乐勤,王循明,徐如良,等.自激振荡脉冲喷嘴结构参数配比试验研究[J].工程热物理学报,2004,25(6):956-958. WANG Leqin,WANG Xunming,XU Ruliang,et al.Experimental study on structural parameters optimized design of the self-excited oscillation pulsed jet nozzle[J].Journal of engineering thermophysics,2004,25(6):956-958.(in Chinese)[9]王瑞和,白玉湖.围压条件下射流流场的数值模拟研究[J].水动力科学进展(A辑),2004,19(1):108-113. WANG Ruihe, BAI Yuhu. Simulation of water jet under ambient pressure[J]. Journal of hydrodynamics(A ser), 2004, 19(1): 108-113.(in Chinese)[10]李江云,王健.低压自激脉冲射流装置频率设计[J].武汉大学学报(工学版).2012,45(4):427-430,467. LI Jiangyun, WANG Jian. Frequency design of low pressure self-excited pulsation jet[J].Engineering journal of Wuhan University, 2012,45(4):427-430,467.(in Chinese)[11]陈颂英,胡涛,曲延鹏,等.低压大流量自激脉冲空化射流试验研究[J].工程热物理,2014,35(10):1965-1967. CHEN Songying, HU Tao, QU Yanpeng, et al. Experimental research of self-excited pulsed cavitation jet in low-press and large-flux[J]. Journal of engineering thermophysics,2014,35(10):1965-1967.(in Chinese)[12]弓永军,郭臣,侯交义,等.基于Fluent的脉冲射流喷嘴的全尺寸结构优化[J]. 液压与气动,2014(11):32-35. GONG Yongjun, GUO Chen, HOU Jiaoyi, et al. Full-size structural optimization of pulsed jet nozzles by Flue-nt[J]. Chinese hydraulics & pneumatics, 2014(11):32-35.(in Chinese)[13]刘爽,李根生,史怀忠.围压条件下脉冲射流提高清岩效果数值模拟研究[J].石油钻采工艺,2015,37(3):6-10. LIU Shuang, LI Gensheng, SHI Huaizhong. Numerical simulation research on improving cleaning cuttings effectiveness with pulsed jet under confining pressure[J]. Oil drilling & production technology, 2015,37(3):6-10.(in Chinese)[14]唐川林,胡东,裴江红.自激振荡脉冲射流喷嘴频率特性实验研究[J].石油学报,2007,28(4):122-125. TANG Chuanlin, HU Dong, PEI Jianghong. Experimental study on the frequency characteristic of the self-exci-ted oscillation pulsed nozzle[J].Acta petrolei sinica, 2007,28(4): 122-125.(in Chinese)[15]王福军.计算流体动力学分析——CFD软件原理与应用[M].北京:清华大学出版社,2004.[16]王循明,焦磊,王乐勤.自激脉冲发生机理数值模拟及参数影响分析[J].浙江大学学报(工学版),2005,39(9):1450-1454. WANG Xunming, JIAO Lei, WANG Leqin. Numerical simulation of self-excited oscillation pulsed jet and analysis of parameters′ influence[J]. Journal of Zhejiang University(engineering science),2005,39(9):1450-1454.(in Chinese)[17]李江云,徐如良,王乐勤.自激脉冲喷嘴发生机理数值模拟[J].工程热物理学报,2004,25(2):241-243. LI Jiangyun, XU Ruliang, WANG Leqin. Numerical simulation of mechanism of the self-excited pulse nozzle[J].Journal of engineering thermophysics, 2004,25(2): 241-243.(in Chinese)[18]董志勇.射流力学[M].北京:科学出版社,2005.