Theoretical analysis of decompression tolerance based on a simulated depressurisation model of an aircraft’s pressurised cabin

Abstract

The method presented in the article is based on a complex simulation model of gas-dynamic processes that take place in sectioned cabins during depressurization. This model allows the theoretical calculation of decompression parameters (decompression time, cabin pressure, gas leakage from the cabin) depending on flight parameters and design features of the aircraft pressurised cabin (height, cabin volume, defect area, etc.) and determine the interdependence of pressure control parameters in critical operating modes. In computational experiments simulating decompression during depressurisation, the rate of cabin pressure drop as a function of the defect area, residual overpressure, decompression time, values of drops between compartment sections and mass flow rate during pressure changes; safe descent height and other parameters were determined. On the basis of computational experiments, a methodology for assessing the portability of decompression was developed, taking into account different levels of impact tolerance, allowing for a rational choice of hermetic and gas dynamic parameters of the cabin, as well as flight performance characteristics, taking into account the possible decompression of the cabin in flight or, conversely, with the specified parameters of the cabin and flight data at the design stage of the aircraft to assess the degree of danger in case of depressurization and to provide in advance a set of security measures. The transition for decompression safety analysis along the Chadov V. I. curve has advantages since it is applicable for various types of aircraft from spacecraft to aircraft and for various atmospheres with different combinations of pressures and concentrations.