In a Tubular Heat Exchanger, the main function of the baffle is to guide the shell-side fluid to flush the tube bundle horizontally and enhance convective heat transfer. By optimizing the baffle spacing (referred to as "plate spacing"), the heat transfer efficiency can be significantly improved.
Mechanism analysis:
Fluid disturbance enhancement: When the plate spacing is reduced, the flow path of the fluid between adjacent baffles is shortened, the flow velocity is locally increased, the turbulence degree is increased, the thermal boundary layer outside the tube is destroyed, and the heat transfer thermal resistance is reduced.
Temperature gradient optimization: The dense baffles cause the shell-side fluid to change its flow direction many times, prolonging the residence time of the fluid in the heat exchange area, promoting the uniform distribution of the temperature difference between the cold and hot fluids, and reducing the local heat exchange dead zone.
Pressure drop balance: It should be noted that too small plate spacing will cause the shell-side pressure drop to rise sharply and increase energy consumption. It is necessary to find the balance point between efficiency and energy consumption by calculating the relationship between the fluid Reynolds number (Re) and the Nusselt number (Nu) based on the fluid viscosity, density and allowable pressure drop.
By scientifically designing the baffle spacing, the heat exchange efficiency can be improved by 10%-30% without increasing the volume of the Tubular Heat Exchanger. This is suitable for energy-saving renovations in chemical, refrigeration and other scenarios.
