Development of optimization method for plate heat exchanger with undulation

The article deals with optimization of undulated heat transfer surface of plate heat exchanger. The goal of optimization is not only to increase effectiveness of heat transfer but also to reduce the pressure drop. A combined pattern of undulation which combines herringbone pattern and wavy pattern was optimized and best values of four parameters were found; angle of herringbone pattern, number, phase and amplitude of longitudinal waves of wavy pattern. The optimization procedure looked for maximum of objective function which was a linear combination of effectiveness and pressure drop. We used simple Monte Carlo method and the optimum was searched for four values of reference pressure drop. Four different optimization were run and we investigated the effect of various definition of objective function and parameters of undulation. It was found that during optimization of combined pattern, the herringbone pattern is more favoured than wavy pattern. It is caused by the fact that herringbone pattern was described by the only one free parameter, which was the angle of undulation, and therefore it is more likely to be found by a stochastic method. This assumption was confirmed when simple wavy pattern was optimized and higher values of objective function and effectiveness were found