Comparison of Correction Factors for Shell-and-Tube Heat Exchangers with Segmental or Helical Baffles

Heat transfer and pressure drop correction factors based on the Bell-Delaware method have been compared for an optimized segmental baffle heat exchanger and a helical baffle heat exchanger. In general, the results showed that properly designed helical baffles offer a significant improvement in heat transfer while providing a reduced exchanger pressure drop. The enhancement in heat transfer for helical baffles was reflected by the so-called turbulence enhancement correction factor, which accounted for the increase in heat transfer observed at a critical baffle inclination angle of 25°. As the baffle inclination angle was increased beyond this critical angle, the turbulence enhancement factor continued to increase and eventually produced a maximum heal transfer enhancement of 1.39 times that for ideal cross-flow conditions. The reduction in pressure drop due to the helical baffles was found to vary from 0.26 to 0.60 depending on the helical inclination angle.