Fluctuation Reduction of Civil Aircraft Vent Fuel Tank NACA Inlet Flow

This paper investigates the flow fluctuation phenomenon in the civil aircraft vent fuel tank NACA inlet, and proposes an improved inlet design to reduce pressure fluctuations based on flow field calculations and analyses. The results show that, the calculated fuel tank pressure results are in good agreement with the flight test data, indicating the reliability and validity of the calculation method and results. These findings can be utilized for the preliminary design optimization of the vent fuel tank NACA inlet. The improved design proposed, featuring a contracted section inside the flow channel, can effectively decrease the pressure difference fluctuation range by 69% and reduce aircraft flight drag by 0.06%.