CAJ | 학술논문

采用全空化模型研究了具有不同物性（黏性、饱和蒸汽压和表面张力）的流体在不同几何形状（入口圆角半径和长径比）喷嘴中的空化现象,用临界空化压力和临界空化数对不同条件下空化的初生进行了分析与表征。结果表明：流体的黏性越大,饱和蒸汽压越小,空化初生的临界压力就越大,而表面张力对临界空化压力没有影响;在入口圆角半径较大和喷嘴长径比较大的喷嘴中,临界空化压力较大,在流体黏性和喷嘴几何形状相同的情况下,虽然临界空化压力会随着流体饱和蒸汽压的变化而变化,但临界空化数基本保持不变;由于喷嘴几何形状的改变造成了流体方向的变化和流体与孔壁之间摩擦损耗的变化,而流体物性的变化影响了流体内部的连续性,因此,喷嘴几何形状和流体物性是影响临界空化压力和临界空化数变化的关键因素。
채용전공화모형연구료구유불동물성（점성、포화증기압화표면장력）적류체재불동궤하형상（입구원각반경화장경비）분취중적공화현상,용림계공화압력화림계공화수대불동조건하공화적초생진행료분석여표정。결과표명：류체적점성월대,포화증기압월소,공화초생적림계압력취월대,이표면장력대림계공화압력몰유영향;재입구원각반경교대화분취장경비교대적분취중,림계공화압력교대,재류체점성화분취궤하형상상동적정황하,수연림계공화압력회수착류체포화증기압적변화이변화,단림계공화수기본보지불변;유우분취궤하형상적개변조성료류체방향적변화화류체여공벽지간마찰손모적변화,이류체물성적변화영향료류체내부적련속성,인차,분취궤하형상화류체물성시영향림계공화압력화림계공화수변화적관건인소。
This paper investigated the effects of fluid characteristics and orifice geometry on cavitation inception in orifice.A full cavitation model was implemented in case of the fluids with different properties（viscosity,vapor pressure and surface tension） and the orifice with different geometries（inlet radius and length-to-radius（L/d） ratio）.The formation and development of cavitation inside the orifice were analyzed quantitatively based on both parameters of critical cavitation pressure and critical cavitation number.According to the numerical simulation,it is revealed that the critical cavitation pressure increases with the increase of fluid viscosity and the decrease of vapor pressure of fluid.But the surface tension of fluid has not relative with cavitation inception.The critical cavitation pressure also increases with inlet radius and length-to-radius ratio.In case of fluids with same viscosity and same orifice,the critical cavitation number has little variation,though the critical cavitation pressure would change with variation of vapor pressure of fluids.Both of critical cavitation pressure and critical cavitation number change from the variations of frictional loss between the wall and fluids,flow direction due to different geometries of orifice;and from the continuity variation in-side fluids due to the variation of fluid properties.