Mathematical Modelling and Optimal Design of Plate-and-Frame Heat Exchangers

The optimal design for multi-pass plate-and-frame heat exchanger with mixed grouping of plates is considered. It is formulated as the mathematical problem of finding the minimal value for implicit nonlinear discrete/continues objective function with inequality constraints. The optimizing variables include the number of passes for both streams, the numbers of plates with different corrugation geometries in each pass, the plate type and size. To estimate the value of objective function in a space of optimizing variables the mathematical model of plate heat exchanger developed. To account for thermal and hydraulic performance of channels between plates with different corrugation patterns, the exponents and coefficients in formulas to calculate heat transfer coefficients and friction factors used as model parameters. The procedure and software for numerical experiment to identify model parameters by comparing the calculation results with those obtained with free available in web computer programs of plate manufacturers is developed. The sets of such parameters are obtained for a number of industrially manufactured plates. The described approach implemented as software for plate heat exchangers calculation. Two case studies results discussed.