## 1 Introduction  
Positive pressure ventilators are an important tool used in rescue and firefighting operations with a wide range of applications [1, 2]. Available on the market are ventilator units powered by both electric and combustion engines [3]. Due to the nature of their use, these devices should be characterized by operational efficiency, which is measured by the generated flow parameters [4, 5]. Flow parameters, including the amount of air injected into the interior of a building, will depend on the device's power [6, 7], rotor size [8] (including the presence of a flow straightener on its surface [9]), rotor blade geometry [10, 11] or mechanisms for changing it [12, 13], and positioning parameters, such as the distance from the door opening and the rotor's angle of inclination. There are numerous scientific studiesin the literature aimed at evaluating the parameters that influence operational efficiency. In 2022, [PERSON] et al. determined the effect of the positioning distance of positive pressure ventilators and changes in the size of the outlet opening on flow parameters (volumetric airflow rate and pressure) in a real building structure [14]. Their research showed that the ventilators operate in completely different ways, i.e., the conventional ventilator generated the highest volumetric flow rate when positioned 1 m away, while the turbo ventilator (with a flow straightener mounted on the rotor) performed best at a distance of 5 m. Similar studies were conducted by [PERSON] and his team [15], who investigated the use of PPV in a three-story building. They demonstrated that the distance at which the ventilator was positioned in front of the door opening affects the amount of air moved. Additionally, they pointed out that the larger the building volume, the less efficient the ventilation with a ventilator becomes due to the larger area where potential structural leaks could occur. In the literature, there are many simulation studies conducted using various Computational Fluid Dynamics (CFD) tools [16; 17]. These programs are widely applied in different branches of industry as well as the scientific environment [18; 19]. [PERSON] et al., in 2024, performed experimental tests and CFD simulations (using Fire Dynamics Simulator FDS) to assess the flow parameters of a mobile ventilator (for positioning distances of 1-7 m) in a multi-story building. A comparative analysis showed a convergence degree between the tests and the simulation from 0.4% to 11.5% (for volumetric flow rate) and from 0.6% to 30.1% for pressure. Furthermore, the authors proposed a method for assessing the air velocity profile in the immediate vicinity of the ventilator's rotor in their publication [20]. In 2006, [PERSON] used the FDS program to assess the air velocity profile in open flow for various positioning distances of the positive pressure ventilator. In his research, he obtained the following convergence degrees between the experiment and CFD simulation: 8.7% (distance 1.8 m), 14.7%--2.4 m, and 3.1% for 3.1% [21]. A similar comparative analysis was also conducted by [PERSON] et al., in 2011 [22]. The authors, in their publication, assessed the possibility of using simple analytical methods and CFD simulations to predict the flow parameters of the air jet generated by a positive pressure ventilator through a building. In the considered building, the authors (between CFD simulation and actual tests) showed the following convergence degree of flow parameters: 2.5% (pressure) and 9.9% (mass flow rate). Furthermore, the authors demonstrated that neglecting structural leaks in the numerical model could overestimate the pressure by approximately 12.5% and the mass flow rate by around 50%. In 2017, [PERSON] et al. conducted CFD numerical analyses related to evaluating the impact of the outlet opening size on the internal pressure within a building's volume [23]. Their research showed that the use of DOAR (Door Open Area Reducer) allows for generating higher internal pressure in the ventilated space by 40-60%.