Passage Arrangement Optimization of Plate-Fin Heat Exchanger under Uncertain Operating Conditions

As the total flow rate and passage number increase, the quality of the passage arrangement has an important influence on the thermal efficiency of a multi-stream plate-fin heat exchanger (PFHE). The operating conditions are uncertain due to changes in environmental and product requirements, which affect the design of passage arrangements. If this influence is not considered enough in design, it will lead to the loss of heat transfer efficiency of the PFHE. Therefore, an optimization design method for passage arrangement is developed considering the influences of uncertain operating conditions. First, the uncertain operating conditions of the PFHE are represented using probability density functions of mass flow rates and temperature. Next, the optimization goals are chosen through the correlation calculation between the passage arrangement and the heat transfer indexes by the integral-mean temperature difference method. The particle swarm optimization algorithm is adaptively improved for the passage arrangement calculation. Then, the result under uncertain operating conditions is compared with the result under a single condition. The total heat transfer rate is increased, and the dimensionless mean square error of the cumulative heat load is decreased, so the method of designing the passage arrangement under uncertain operating conditions is effective.