2개의 블레이드로 구성된 회전익 끝와류들의 간섭 특성

Abstract

Key Words: Rotor Blade(로터블레이드), Wake Age(후류시기), Tip Vortex(끝와류), Vortex Filament(와류필라멘트), LDV(레이저도플러유속계), Vortex Stretching(와류이완)초록: 대칭익형단면에미세한피치각의차이를가지는두개의로터블레이드의끝에서발생하는와류들의상호간섭을관측하기위하여2차원LDV를활용하여끝와류의회전속도성분과축방향속도성분들을후류시기에따라서측정하였다. 선행블레이드는끝와류축방향성분이정규분포를나타내는상사성을위배한반면, 후행블레이드는회전속도성분이복합와류를나타내는Vatistas' n=2 모형의상사성을위배하는것으로관찰되었다. 또한, 후류시기200~240도근방에서두끝와류의궤적이근접되어상호간섭을나타내는것으로밝혀졌으며이시기동안후행블레이드의와류이완현상이발생하는것으로확인이되었다. 이러한후류간섭은관절형허브를가지는로터에서도발생될것으로예측된다.Abstract: In order to observe the wake interaction between tip vortices generated by a two-bladed rotor withslightly different pitch angles, the velocity components of the tip vortices were measured by using atwo-dimensional LDV system. It was observed that the swirl velocity components of the ensuing bladedeviated from the Vatistas' n = 2 vortex model and the axial velocity components of the preceding bladedeviated from the Gaussian profile. It was also found that in the wake-age range of 200o to 240o, thefilament of the ensuing blade tip vortex was stretched as result of the closing in of two vortices. The resultsfrom these observations suggest the possibility that a similar wake interaction is generated in actual rotorblades, especially, in the ones with articulated hubs.