Numerical Calculation And Analysis On A Ram Air Turbine

This paper numerically simulates a ram air turbine with NUMECA software, and gains the general performance curves of the turbine. By analysis the flow field of the ram turbine, it also gains the particular vortices of both stator blade rows and rotor blade rows, as well as the distributed regularities. The results show that the root blade profile of the rotor is not appropriate according to the aerodynamic performance, which should be improved combined with the stress intensity analysis.By studying the tip clearance of the rotor of ram air turbine, the results show that with the increase of the value of the tip clearance, the flow pattern in the tip clearance varies with the ratio between the value of the tip clearance and local thickness of the rotor blade. The flow pattern in the tip clearance determines the magnitude of leaking flow, as a result, the vortices produced by the leaking flow change consequently, which makes a full impact on the vortices of rotor blade rows. Since the flow pattern in the tip clearance and vortices of rotor blade rows changed, the loss distribution of the rotor will change, which will make the proportion of mixture losses in the tip clearance decrease while the proportion of mixture losses in the rotor blade rows increase. In conclusion, as the value of the tip clearance increases, the total losses keep increasing and the efficiency keep decreasing. By studying the tip clearance, the results also show that the load ability of the tip of the rotor blade decreases, so do the moment and the power of the turbine axle. This paper also studies the difference of the flow pattern and losses of the rotor between motion and static. On the basis of fully analysis, a reasonable value of the tip clearance was given in this paper.In the end, through numerical simulation, this paper also analysis the influence of the inlet device to the performance of the ram air turbine. Compared with no inlet device, when the ram air turbine has the inlet device, the performance of the ram air turbine will decrease. But the decrease is very small.