High altitude airships possess tremendous potential for long-endurance spot hovering platforms for both commercial and strategic applications. The energy system, which is mainly made up of solar array and regenerative fuel cell, is the key component of a high altitude airship. The thermal effect is a major factor that affects the performance of the energy system of long endurance stratospheric vehicles. In this paper, a conceptual design method focusing on the thermal and power characteristics of an energy system for stratospheric airships is proposed. The effect of thermal behavior of solar array on the energy system is analyzed. An optimized case is obtained on the consideration of power supply, thermal behaviors of helium and solar array. Results show that the maximum temperature difference of the solar array may be reduced by about 20 K and the mass of payload can be improved by up to 5%.

In the process of aircraft operation, the flow calibration of aircraft liquid cooling system has always been one of the research hotspots in engineering. Based on the principle of the differential pressure method, a new experimental flow calibration method is proposed for the aircraft liquid cooling system in this paper. In the reducer and the square bend of the aircraft liquid cooling system, the pressure difference will be generated. The flowmeter is used to measure the flow of the coolant, and the flow rate coefficient of the aircraft liquid cooling system can be calibrated. The experimental platform is established to conduct the flow calibration of the aircraft liquid cooling system, and the influence of the temperature and imported pressure on the flow will be investigated. Results indicate that the experimental method proposed is very effective, and the flow calibration can be realized without damaging the aircraft liquid cooling system.