Simulation Study on the Influence of Engine Room Wake Field on the Perceived Total Pressure of Ejection Seat Pitot

An approach to simulate the total pressure of the pitot during ejection is proposed by combining the numerical simulation of seat motion trajectory and dynamic CFD technology in this paper. By establishing the simulation model of cabin, human-seat system and pitot, the seat motion parameters obtained from the simulation of the motion trajectory are used as input to write the UDF, the motion boundary of the human-seat system is specified, and the grid update during the movement of the seat is realized by dynamic grid method, and the influence of the wake field of the cabin on the total pressure of the pitot under different ejection states is analyzed. The simulation results show that due to the influence of the wake field of the cabin, the perceived total pressure of the pitot first increases and then decreases, peaks at about 0.08s after ejection starts, and is greater than the test total pressure in the subsequent 0.01s time range, and the maximum deviation reaches 14.65%. This peak can be reduced by filtering, reducing the deviation to less than 5%. The simulation model and algorithm are calibrated, and the deviation is less than 2%, which meets the engineering requirements, and the simulation results can provide a basis for the optimization of seat aerodynamic layout and program controller data processing strategy.