Design And Performance Analysis Of General Aircraft Hybrid Electric Propulsion System

Hybrid electric propulsion technology is the core technology for the future development of the aviation industry,and has the potential to meet the demanding requirements for energy saving and emission reduction in the aviation industry in the future.Hybrid electric propulsion systems are considered to replace traditional power and propulsion systems,providing core thrust for high power level aircraft such as general aircraft,commercial aircraft,military aircraft and vertical take-off and landing aircraft.The efficient,effective and generic hybrid electric propulsion system overall design method could transform the flight mission load and distance demand into the design requirements of the power and propulsion system and reduce the number of iterations of the detailed components design and preliminary overall system design,which could improve the efficiency of the whole research and development process.A detailed analysis of the overall design results will also be helpful to further decompose the key bottleneck techniques for the future development of hybrid electric propulsion technology.The existing researches on the overall design of hybrid electric propulsion system mostly started from the small UAV platforms,ignoring the influence of the weight and power consumption of the thermal management system.A large system error might occur if these methods were applied to the overall design of the high power level power and propulsion system,making the preliminary overall design invalid.In this paper,the zero-dimensional forced convection heat transfer model of thermal management system was established,integrated with the series hybrid electric distributed propulsion system design framework,in which the total power requirement was the sum of propulsion power and thermal management power consumption.A preliminary overall design method for hybrid electric propulsion system considering thermal management system based on multi-task profile power requirements was established.The model verification results showed that the calculation accuracy of the method could meet the requirements of the preliminary overall design and performance analysis of the system.The overall design results and basic performance of the series hybrid electric distributed propulsion system were obtained through this design method,which showed that the series hybrid electric distributed propulsion aircraft was more economical and environmentally friendly than the traditional aircraft when the distributed coefficient exceeded1.3.The hybrid electric propulsion aircraft with better aerodynamic performance could meet the requirements for energy saving and emission reduction in the future aviation industry.Through the system fuel consumption analysis and parameter sensitivity analysis,the key technologies for improving the performance of hybrid electric propulsion system were obtained,including the distributed coefficient improvement,lightweight design of thermal management system,thermal management power consumption reduction,power weight ratio improvment of the motors and energy density improvement of battery cell,etc.The method was used to quickly obtain the preliminary overall design scheme and performance of the series hybrid electric distributed propulsion system for a certain general fixed-wing aircraft,which could be further used for the detailed design of the system and components.The design case results showed that the application of the series hybrid electric distributed propulsion system could improve the economics of the aircraft under the current technology of electrical components and thermal management systems.