Aerospace Instrument-Making Annotation << Back Mathematical Modeling of the «Artificial Lungs–Isolation Breathing Apparatus» System: Assumptions, Structure, and Validation Approaches Gomzov N.V., Slezin K.A., Gromov Yu.Yu., Pogonin V.A. The article presents a mathematical model of the "Artificial Lungs – Isolating Breathing Apparatus" (AL– IBA) system, de-signed to analyze and predict the performance of isolating respiratory devices in hazardous atmospheres. The model accounts for key processes: gas exchange, CO2 sorption, heat transfer, and gas fl ow hydrodynamics. A set of physically justified assumptions, such as ideal gas mixing, isothermal processes, and laminar fl ow regime, is introduced to simplify the model. The system is de-composed into interconnected subsystems formalized using ordinary differential equations and algebraic relations. Full-scale ex-periments will be conducted for model verification and constant adjustment. The model is expected to analyze O2 and CO2 con-centration dynamics, predict the protective duration of the regenerative cartridge, optimize its design, and enable virtual testing under extreme conditions, thereby reducing the scope of costly physical tests and accelerating the development of new respiratory protective equipment. Keywords: insulating breathing apparatus, artificial lungs, gas exchange, regenerative cartridge, mathematical model. DOI: 10.25791/aviakosmos.11.2025.1518 Pp. 27-32.