###### Abstract
This direction of scientific research is popular and rapidly growing today. Additional research results on this topic are given in articles [15; 16; 17]. Thus, swirling the flow in front of the diffuser is an effective method for intensifying thermophysical processes both inside the diffuser and downstream from it. There are scientific and technical studies on the development of methods for controlling the gas dynamics of flows in conical diffusers to optimize thermogas-dynamic processes in machines and devices [18; 19; 20]. [PERSON] et al. used a Karman-vortex generator to reduce flow separation in conical diffusers with large opening angles (more than 18 degrees) [18]. This made it possible to avoid early flow separation (collapse) in the expanding section of the diffuser. [PERSON] et al. used a spiral ribbon insert in a diffuser to create additional flow recirculation [19]. This contributed to a significant improvement in the distribution of air flow velocity throughout the volume of the conical diffuser. [PERSON] and [PERSON] proposed various designs of inlet channels to control the air flow structure in a conical diffuser [20]. The design (in particular, the cross-section shape of the inlet channel) has a significant effect on the flow velocity field in the diffuser and cylindrical section. Accordingly, the development of active and passive methods for controlling the gas-dynamic flow structure in conical diffusers remains a promising and technologically advanced task in science and technology. Fine-tuning the design (opening angle, diameter, length, degree of displacement, etc.) of the diffuser is also a pressing issue among scientists and specialists to improve the efficiency of technical and technological devices [21; 22; 23]. [PERSON] et al. studied the influence of the diffuser diameter (from 0.6 to 6.0 m) on the gas-dynamic and consumable characteristics of the flow for a constant velocity of 6.5 m/s [21]. [PERSON] et al. studied the influence of a set of geometric dimensions of a conical diffuser on gas dynamics and performance [22]. [PERSON] et al. refined the design of the turbine outlet diffuser to improve flow characteristics and increase the efficiency of the turbine [23]. The geometric dimensions of the conical diffuser have a noticeable effect on the integral gas-dynamiccharacteristics of the flows. Therefore, the design of the diffuser must be calculated and selected very carefully for each specific case, taking into account both the purpose and objectives of operation. The properties of the working media also have a noticeable impact on the gas-dynamic, consumable and heat-exchange characteristics of flows in conical diffusers [24; 25; 26; 27]. [PERSON] and [PERSON] studied the detailed gas-dynamic characteristics of gas and solid particles in a vertical conical diffuser for different boundary conditions based on mathematical modeling [24]. The main goal was to create the most uniform distribution of solid particles in the diffuser volume. [PERSON] and [PERSON] also modeled the distribution of solid particles inside a conical diffuser [25]. The aim of the study was to find the diffuser geometry and flow parameters required to eliminate the accumulation of particles in the corners of the diffuser. There are also studies of flow characteristics for working media in the form of incompressible fluid [26] and nanofluids [27]. The physicochemical properties of fluids have a significant impact on the thermogas-dynamic characteristics of flows in conical diffusers. The importance of further research into the gas dynamics and heat transfer of flows in conical diffusers is determined by its wide application in hydraulic turbines [28], gas turbines [29], Francis turbines [30], power plants based on the Organic Rankine Cycle [31], ventilation and air conditioning systems [32] and many other applications. It should be emphasized that scientists do not pay enough attention to the detailed study of gas dynamics in diffusers based on experimental data.