A numerical simulation was used to investigate heat transfer in plate-fin radiators with round fillet profiles of various depths, including 0.55 mm, 1.1 mm, and 1.5 mm. The issue of flowing air around a radiator with a mass flow rate of 10-3 to 4·10-3 кг/с and a temperature of 293 K was solved. The radiator was heated using a heater, whose temperature was set from 323 to 353 K. Changes in heat flow, pressure drop, and energy efficiency indicator were shown depending on the air mass flow, according to the calculation results. The research findings indicate that the radiator featuring round fillet profiles and a depth of 1.65 mm exhibits the highest heat flow and energy efficiency indicators, as well as the lowest pressure drop.

Keywords: radiator, cooling system, numerical modeling, computational fluid dynamics, heat transfer, heat flow, pressure drop, energy efficiency, calculation, electronics

Using numerical simulation, we carried out studies on the effect of the length of a porous heat exchanger on the deposition of dust particles. The heat exchanger models with lengths of 5, 10, 20 and 30 mm were the subject of the studies. At the boundaries of the computational domain, we set the air velocity at 0.1, 1, and 5 m/s and the diameter of dust particles from 10-7 to 10-4 m. Research results have shown that with increasing length of the porous heat exchanger, the efficiency of dust particle deposition increases. This can lead to a decrease in the thermal and hydraulic characteristics of the heat exchanger.

Keywords: porous media, heat exchanger, numerical simulation, calculation, deposition of dust particles, heat exchanger length, air flow velocity, particle diameter, air cooling, microelectronics

An original approach to describe airflow in the thin conic diffusor is suggested. It is based on approximate analytic solution of continuity equation. In addition simplified model of turbulence is combined. Reliability of derived formula is confirmed by comparison with finite-element solution for designed experimental setup. The elaboration is intended to direct computer simulation of multiphase flow.

Keywords: dust-air mixture, aspiration systems, turbulence, finite element modeling, separation diffuser, digital twin

A program for computer simulation of atomization of liquid fuels has been developed. A special calibrating experiment was carried out in a gravitational field. Verification of the computer model with experimental data is carried out, the correctness of simulation modeling is determined by the convergence of the results of static generalization. Tests of a model sample of the burner device were carried out, confirming the adequacy of computer simulation.

Keywords: burner, atomization of liquid fuels, mathematical modeling, fuel jet dispersion dynamics, nozzle