CAJ | 학술논문

风琴管自振空化喷嘴因兼具空化射流与脉冲射流的优点而被广泛使用.为探究大雷诺数下风琴管喷嘴内表面粗糙度对高压射流特性的影响,从而提高喷嘴作业效率.在理论分析紊流特性与表面粗糙度关系的基础上,通过试验探究了风琴管喷嘴内表面粗糙度对射流轴心压力脉动与扩散角的影响规律.试验结果表明,入口压力越大,粗糙度对射流的扩散角、轴心压力脉动峰值、压力脉动幅度的影响程度越大;对某一入口压力,存在一对应起始粗糙度值使得扩散角快速增大,轴心压力脉动峰值与压力脉动幅值急剧衰减;且入口压力一定时,存在一临界粗糙度值,粗糙度小于此值时,轴心压力脉动峰值与压力脉动幅值随靶距增大而先增大后减小;粗糙度大于此值时,轴心压力脉动峰值与压力脉动幅值随靶距增大而减小.根据试验数据,运用能量守恒定理,建立了射流轴心压力脉动峰值随表面粗糙度、入口压力、靶距变化关系的初步数学模型.
풍금관자진공화분취인겸구공화사류여맥충사류적우점이피엄범사용.위탐구대뢰낙수하풍금관분취내표면조조도대고압사류특성적영향,종이제고분취작업효솔.재이론분석문류특성여표면조조도관계적기출상,통과시험탐구료풍금관분취내표면조조도대사류축심압력맥동여확산각적영향규률.시험결과표명,입구압력월대,조조도대사류적확산각、축심압력맥동봉치、압력맥동폭도적영향정도월대;대모일입구압력,존재일대응기시조조도치사득확산각쾌속증대,축심압력맥동봉치여압력맥동폭치급극쇠감;차입구압력일정시,존재일림계조조도치,조조도소우차치시,축심압력맥동봉치여압력맥동폭치수파거증대이선증대후감소;조조도대우차치시,축심압력맥동봉치여압력맥동폭치수파거증대이감소.근거시험수거,운용능량수항정리,건립료사류축심압력맥동봉치수표면조조도、입구압력、파거변화관계적초보수학모형.
The organ-pipe nozzle is widely used because of its generation of self-resonating cavitating jets which combines the advantages of cavitating jets and pulsed jets. In order to improve the working efficiency of organ-pipe nozzle by studying the influence of internal surface roughness on the characteristics of high pressure jet under high Reynolds numbers, the relations between turbulent boundary layer and surface roughness are theoretically analyzed, and the laws of the axial pressure fluctuation and the diffusion angle of the jet are investigated by experiment. The results show that, the peak pressure, the rage of pressure fluctuation and the diffusion angle are influenced more greatly by the surface roughness when the inlet pressure is greater. There exists a minimum roughness number, above which the diffusion angle starts to increase while the peak pressure and the rage of pressure fluctuation starts to decrease greatly. For a certain inlet pressure, there exists a critical roughness number, below which the axial pressure fluctuation increases at first and then decreases with the increase of stand-off distance, while above which the axis pressure fluctuation only decreases when the stand-off distance increases. Based on the experimental data, a preliminary mathematical model of the axial peak pressure relating to inlet pressure, internal surface roughness and stand-off distance was established by utilizing the principle of conservation of energy.