A tip-covered vortex generator concept to enhance film cooling on plain and curved surfaces

Traditional film cooling with cylindrical-hole faces two challenges: (1) coolant is mainly concentrated downstream of the cooling hole center, and (2) coolant is easily lifting-off the wall at high blowing ratio conditions. Although the installation of vortex generator (VG) helps to enhance the coolant coverage, it still encounters with the limited cooling effect improvement. To solve these difficulties, this paper presents a new VG design, named tip-covered VG (TCVG), to enhance the film cooling effectiveness on the plain and curved surfaces. To demonstrate the feasibility of this design, numerical simulations are performed between the traditional film cooling with cylindrical-hole (just-hole case), film cooling with traditional VGs (TVG case), and film cooling with tip-covered VG (TCVG case). The results show that, with the TCVG, the film cooling effectiveness can be improved by 25 % and 9 % as compared with the just-hole case and TVG case, respectively.