Analysis of aircraft integrated thermal management using fuel as heat sink

摘要

In order to effectively remove heat load created by oil system, hydraulic system, cabin and airborne electrical equipment on the aircraft, fuel is selected to be heat sink. Using fuel as heat sink results in the rise of fuel temperature, so fuel is required to dissipate heat through tank walls and exchange heat with air by air-fuel heat exchanger to ensure that the heat-absorbing capacity of fuel is sufficient. And fuel temperature of tanks is required to be calculated in the whole flight envelope based on the given powers of air-fuel heat exchanger, which is used to examine if fuel temperature meet the limitation of safe temperature. Before this, inner and outer convective heat transfer coefficients of tanks have to be known in the calculation of the heat dissipation of fuel through tank walls. FLUENT is utilized to conduct three-dimensional flow field simulation of aircraft and each tank to get outer and inner convective heat transfer coefficients. FLOWMASTER is applied to make a simulation of the aircraft integrated thermal management to obtain inlet parameters of fuel tanks, which could be used as boundary conditions of FLUENT. Then fuel temperature could be calculated by using overall heat transfer differential equations. The results show that it is the best choice for fuel temperature control when the power of air-fuel heat exchanger is 10 KW. The idea of this paper can be used as a back-up plan in the aspect of aircraft integrated thermal management.