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The purpose of this paper is to analyze the effects of the PRD geometric parameters, including the area and aspect ratio, on the discharge and force characteristics of pressure relief process under various plenum compartment pressures and Mach numbers.

Under various plenum compartment pressures and Mach numbers, the effect of the area and aspect ratio on the discharge and force characteristics of the PRD are numerically investigated via a three-dimensional steady Reynolds-averaged Navier–Stokes equations solver based on structured grid technology.

When the aspect ratio remains constant, the discharge coefficient C_D, thrust coefficient C_T and moment coefficient C_M are not affected by the PRD. When the area is constant, the aspect ratio dramatically impacts the discharge and force characteristics because the aspect ratio increases, the discharge coefficient C_D of the PRD decreases, and the thrust coefficient C_T and the moment coefficient C_M both increase. When the aspect ratio is 2, the discharge coefficient C_D decreases by 14.7 per cent, the thrust coefficient C_T increases by 10-15 per cent, and the moment coefficient C_M increases by 10-23 per cent compared with when the aspect ratio is 1.

This study provides detailed data and conclusions for nacelle PRD researchers and actual engineering applications.

On the basis of considering the influence of operating conditions on the discharge and force characteristics of the nacelle PRD, the impact of geometric parameters, including the area and aspect ratio on the discharge and force characteristics is comprehensively considered.

The purpose of this study is to measure the mass diffusion coefficient of nitrogen in jet fuel using digital holography interferometry for cost-effective designing and modeling of the aircraft tank inerting system.

The mass diffusion coefficients of N₂ in RP-3 and RP-5 jet fuels were measured by digital holography interferometry at temperatures ranging from 278.15 to 343.15 K. The Arrhenius equation is used to adequately describe the relationship between mass diffusion coefficients and temperature. The viscosities of RP-3 and RP-5 jet fuels were also measured to examine the accuracy of the Stokes–Einstein model in calculating mass diffusion coefficients.

As temperature increases from 278.15 to 343.15 K, the mass diffusion coefficients increase 4.23-fold for N₂ in RP-3 jet fuel and 5.13-fold for N₂ in RP-5 jet fuel. The value of Dµ/T is not constant as the Stokes–Einstein equation expressed, but is a weak linear function of temperature.

A more accurate diffusion model is proposed by fitting the measured Dµ/T with the temperature and calculating the mass diffusion coefficients of N₂ in RP-3 and RP-5 jet fuels within 10 per cent relative deviation.

A measurement system for mass diffusion coefficients of N₂ in RP-3 and RP-5 jet fuels was constructed based on the digital holography interferometry. The mass diffusion coefficient can be expressed by a uniform polynomial function of temperature and viscosity.