Abstract:

Tubular heat exchangers, which are frequently used in industrial processes, are devices that transfer the heat of two fluids at different temperatures without mixing. With the use of a turbulator, the integrity of the flow boundary layer is disrupted and shattered, additional turbulence is given to the environment of the flow, secondary flows occur in the environment of the flow and effects such as increasing the flow distance of the fluid as a result of the variation of both the fin pitches and the blade angles of the turbulators. In this study, turbulators are used in counter flow tube heat exchangers. From the area between the two pipes, water at a constant volumetric flow of 50 l/h and a temperature of 298.14 K passes, while air at a temperature of 350 K passes through the inner pipe. The annular type turbulators placed in the inner pipe were examined numerically in different steps. Pressure losses and friction characteristics were investigated for the range 4000 - 26000 of Reynolds number for each turbulator. Using the digital fluid dynamics code program, which performs analysis based on the finite volume method, the basic conservation equations are solved in steady-state, 3-dimensional and turbulent flow conditions. Numerical analysis results were obtained in the study conducted according to different speeds of the air. Pressure and velocity distributions are created within the pipe as a result of numerical analysis. Compared to the empty heat exchanger, the pressure drops caused by the turbulator was observed to occur for the turbulator with a minimum pitch of 100 mm and a maximum step of 25 mm. It was concluded that the pressure drops increase with the shortening of the step distance in the turbulators, and the pressure drops increase with the increase of the Reynolds number.

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