Flow and Heat Transfer in a Pre-Swirl Rotor-Stator Cavity under High Rotational Reynolds Number

A three-dimensional numerical study of the flow and heat transfer characteristics of a pre-swirl rotor-stator system equipped with a series of pre-swirl nozzles of circular cross-section was carried out.Pre-swirl nozzles were located on the outer rim of a stator disk with a radius equal to that of the rotor blade inlet holes.The RNG k-ε turbulent model was used for the simulation under the condition of high rotational Reynolds Number and throughflow rate.The convective heat transfer coefficients of the rotor and temperature distributions at the blade inlet holes were obtained for different non-dimensional throughflow rates and rotational Reynolds Numbers under a given swirl angle.The computational data were compared with that of a simple straight air inflow model.The results show that the cooling air total temperature entering the rotor blade holes is obviously lower with the pre-swirl nozzles compared to the straight nozzles without pre-swirl.The convective heat transfer is enhanced inside the cavity by increasing the non-dimensional throughflow rates and rotational Reynolds Number.And the cooling air temperature entering the rotor blade holes decreases with the increase of the non-dimensional throughflow rates,whereas it goes up and then drops down with the increase of the rotational Reynolds Number.