Intensification of the heat dissipation capacity of tubular heat exchange devices of diesel locomotives
The paper shows that the relatively low heat dissipation capacity of the heat exchange devices of locomotives is due to a violation of the structure of the turbulent flow along the section of the cooler tubes (large turbulence occurs in the middle part of the flow) and a decrease in the water velocity in the wall layers. The flow of the coolant in this mode leads to a loss of 30 to 45% of the heat dissipation capacity of heat exchange devices. It is proposed to improve the heat exchange devices of the water-air and water-oil cooling systems of diesel diesel by supplementing in their design devices that intensify convective heat exchange in the wall layers of the liquid of the cooling tubes. Organized turbulent mixing, mainly in the wall and intermediate zones of the tube flow, increases (from 20 to 50%) the efficiency of heat exchange of water-air sections of radiators and oil heat exchangers. A comparative evaluation of the complex indicator of the thermal and hydrodynamic efficiency of various methods of increasing heat transfer in tubular heat exchange devices has been performed. It is shown that the most rational device that intensifies the turbulent flow of a liquid coolant in a wall layer with a developed vortex circulation is a single-pass wire spiral placed inside each cooling tube during assembly. To increase the length of the wall turbulence zone, the wire spiral is installed coaxially with a gap relative to the tube wall.