Extension of Aircraft Thermal Endurance by Multi-Return Fuel Tank System

To extend the thermal endurance of the aircraft, a new fuel thermal management system with multi-return flow paths to the fuel tanks (MRFTS) is proposed. Compared with the traditional single return fuel tank system (SRFTS), the biggest difference is the hot fuel can also be returned to the auxiliary tanks in the MRFTS. The flow selector of the MRFTS is equipped with a temperature control strategy, which can keep the system temperature below but approaching the limit values to achieve the acceleration of the waste heat dissipation. And the fuel consuming sequence of the actual fuel tanks has been fully considered in this control strategy. By the numerical calculation of the high-power condition, the thermal endurance of the MRFTS is increased to 3319.8 s while the thermal endurance of the SRFTS is only 389.5 s, which means utilizing the large amount of the heat sink of the auxiliary tanks can significantly improve the aircraft thermal endurance. Furthermore, a mission profile with a long-time aircraft engagement is analyzed as well, which indicates that the MRFTS can control the system temperature not exceeding the limit values by the dynamic selections of the return tanks while the SRFTS cannot meet the thermal management requirements during the engagement stage. Therefore, the MRFTS can extend the aircraft thermal endurance effectively during the entire flight process with the high thermal load.