The object of this research was the mixing chamber of a turbofan engine. The subject of this study was the thermogasdynamic processes in the mixing chamber of the turbojet engine before the turbine of the turbofan stage. Such engine designs, known as dual-flow engines with a rear-mounted turbofan stage, are based on single-flow turbojet engines. The main disadvantage of the design layout of a turbojet engine with a rear-mounted turbofan stage is the significant temperature non-uniformity of the flow in the turbofan stage channel: the inner part – the turbine part of the working wheel is swept by hot gas after the turbine with a temperature of T = 800...900 K; the outer part of the stage, which works as a fan for the second circuit, is swept by an air flow with atmospheric air parameters. This leads to a high level of thermal stress in the working blades of the wheel. The main feature of the working process of a turbofan engine compared to a turbojet engine is that to generate power in the turbofan, the turbine uses the energy of the gas flow from the mixing chamber of the first and second circuits. In the mixing chamber, energy exchange occurs between the air in the second circuit of the gas generator and the gas flow behind the gas generator turbine. The aim was to conduct a computational study of the mixing chamber to analyze the temperature distribution at the outlet of the mixing chamber. To achieve this goal, the following tasks were performed: calculate the mixing chamber and find the optimal mixing parameters based on the parameters of the mixing chamber. An analytical method and numerical experiment method were chosen to study the flow in the mixing chamber. As a result, a study of the temperature distribution at the outlet of the mixing chamber yielded a temperature distribution. The optimal temperature parameters in the mixing chamber were found depending on the degree of dual flow. The practical significance of the results is that they can be used in afterburning turbojet engines and three-flow turbojet engines.