Numerical study of using dean vortices to enhance the film cooling performance for fan shaped hole

With the maturing of additive manufacture anticipated in the future, more freedom in film cooling hole design will be obtained. Exploiting this freedom, the present authors designed a new film cooling hole using curved holes to generate Dean Vortices within the fan-shaped hole?s delivery line. The Dean Vortices interacts with the kidney vortices in the coolant and mainstream mixing region. Numerical results, including the film cooling effectiveness values (q), the flow field, heat transfer coefficients (h), and the net heat flux reduction (NHFR) are compared between a laidback, fan-shaped hole (SH), the curved shaped hole (CSH), the reversed curved shaped hole (RCSH) and the round hole (RH) with blowing ratio, M, of 0.5, 1.0, 1.5, 2.0 and 2.5. The comparison shows that film cooling effectiveness values with the CSH and RCSH are higher than the SH or the RH at every M studied. Due to the high kinetic energy transferred to the near-wall region for the CSH and RCSH cases, there is h enhancement on the surface, however. Nevertheless, the CSH and RCSH still display higher NHFR at every M studied than the SH or the RH cases. ANSYS CFX 18.2 and the RNG k-e model equations were employed to do the simulations.

Automated summary

This study presents a new film cooling hole design using curved holes to generate Dean Vortices for enhanced cooling effectiveness. The comparison of different hole shapes at various blowing ratios reveals that the curved and reversed curved holes exhibit higher film cooling effectiveness values.