Abstract:
The propeller is a fundamental part of an aircraft powered usually by the turboprop, piston engines or by electric motors. Propeller driven aircrafts have a higher propulsive efficiency than aircrafts with other types of engines. A propeller that spins efficiently through air directly results in environmental friendly and cost effective flights as less torque and consequently, less power is required form the engine to turn the propeller.
The objective of this thesis was to study the effect of leading edge tubercles on propeller efficiency. Various aspects were studied including the effect of varying the tubercle wavelength and amplitude on propeller efficiency, the effect of leading edge tubercles on propeller diameter to pitch ratio, the effect of tubercles on propeller solidity and the effect of tubercles on propeller performance with respect to Reynold’s number.
Small sized aeronautic propellers were considered for this research. The calculations for thrust and torque coefficients were performed via numerical simulations carried out on the commercially available SolidWorks Flow Simulation Premium© package. The numerical simulations were run at various rotational velocities and advance ratios. This was done to make the analysis thorough.
The results indicate an increase in efficiency of the modified propeller in comparison with the baseline propeller while operating at a various rotational velocities and flight speeds. An average of 14.21 % efficiency improvement was observed for the modified 8x3.8 propeller; average of all configurations; while the average efficiency improvement for the modified 5x3 propeller was at 7.97 %; average of both three and four blade configurations; and the modified 11x3.5 propeller had an average of 39.69 % increase in efficiency. This can be attributed to the tubercles added to the leading edges of the modified propeller blades.
A propeller driven aircraft with a modified propeller installed in place of a baseline propeller; with an increased thrust to torque ratio; will have the potential for a higher maximum rate of climb, lower time to climb, higher absolute and service ceilings, a higher maximum velocity, a higher range and endurance and greener aviation.
