Prediction of momentum, heat and mass transfer in chevron-type plate-and-frame heat exchangers

Plate and frame heat exchangers are nowadays mainly built up from plates with chevron-type corrugation patterns. Similar periodic structures are applied as static mixers and as packings in columns. The inclination angle of the crests and furrows of the sinusoidal chevron-type pattern against the main flow direction has been shown to be the most important design parameter with respect to fluid friction and heat transfer. A relatively simple model equation for the friction factor xi as a function of the inclination angle cp and the Reynolds number has been developed. Heat and mass transfer coefficients are then obtained from a purely theoretical equation for developing thermal boundary layers in fully developed laminar or turbulent channel flow the generalized Leveque equation: Nu/Pr-1/3 =Sh/Sc-1/3 =1.615[(xi Re/64)Re d(h)/L](1/3) with db as the hydraulic diameter, L as the distance between two crossings, and Lambda as the wavelength of corrugation so that d(h)/L = (d(h)/Lambda)sin(2 phi). It is shown by comparison with data from the literature, that this type of analogy between momentum, heat and mass transfer is in reasonable agreement with experimental observation.