No abstract

No abstract

Using an electric propulsion system instead of internal combustion engine power, electric aircraft have the advantages of energy conservation and environmental protection. This paper proposed an analysis method of the water cooling system for the frequency converter of an electric aircraft which aims at increasing the power density of the frequency converter. The turbulence of the cooling water influence heat dissipation, which is important in the calculation of fluent field. Based on fluent field calculation, the relationships between the flow quantity and temperature, the flow quantity and pressure, the flow velocity and temperature, and the flow velocity and pressure of the water cooling system are received, which guided the design of the water cooling system. Then the flow quantity is determined to be 0.8m3/h, the cross-section of the cooling water channel is determined to be 9.5mm×10mm, and the maximum temperature of the converter frequency is 67.27°C, which is verified by the experiment. The calculation results for the final water cooling system are within usage requirements which benefit future design.

The takeoff process of a seaplane is different from that of a conventional land-based plane owing to the influence of hydrostatic, hydrodynamic, and aerodynamic forces. As a result, more energy will be consumed by the electric propulsion unit (EPU) of a seaplane during takeoff. Given the limited energy density of contemporary batteries, the energy consumed by the seaplane during its flight mission profile was minimized in this study by improving the efficiency of the EPU using a proposed optimization method. To meet the performance requirements of the seaplane EPU, the pitch angle of the propeller was taken as the optimization variable and the system loss was mathematically modeled. The performance of the EPU was thereby optimized, its consumption during flight was reduced, and the seaplane endurance was increased accordingly. The proposed optimization method was subsequently verified using a prototype test of a twoseat electric seaplane. The results show that the proposed method can reduce the energy consumption of the EPU by more than 5% during a single flight. INDEX TERMSElectric seaplane, electric propulsion unit (EPU), energy efficiency optimization, prototype test. NOMENCLATURE ρ Air density. C T Propeller thrust coefficient. β Propeller power coefficient. S Wing area. C D Aerodynamic drag coefficient. C L Aerodynamic lift coefficient of the aircraft. c r Water friction resistance coefficient. ρ w Water density. B Float width. N P Number of floats. EPU Electric propulsion unit. θ Pitch angle.The associate editor coordinating the review of this manuscript and approving it for publication was Adamu Murtala Zungeru .