Numerical simulation of vortex ring state phenomenon for the Mi2 type helicopter tail rotor

The paper presents computational simulations of loss of helicopter tail rotor effectiveness (LTE) effect caused by rotor vortex ring state (VRS) phenomenon. The phenomenon is critical for safety of helicopter operations and it was an important factor in some military and civil helicopters serious accidents. Analysis was conducted on the example of the tail rotor of Mi2 and PZL Kania single main rotor medium helicopters, which are still in wide use in some parts of the world. That kind of dual blades tail rotor was designed with symmetrical NACA0012 airfoil. Full three-dimensional analysis of the flow around real geometry of the rotor blades was conducted by application of commercial solver Ansys Fluent. The simulation was made by resolving Unsteady Reynolds Averaged Navier Stokes equations by finite volume method with use of Moving Mesh and Moving Reference Frame techniques. A hover turn over a spot was chosen as flight condition of helicopter, which could induce the LTE phenomenon. Thrust and power consumption were estimated during computations. Visualization of the flow field and pathlines of the flow were presented for chosen stages of vortex ring formulation around the rotor. The sensitivity of dual blades tail rotors, which are popular in light and medium type of helicopters to LTE phenomenon, was estimated.

---

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.