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Traditional pinch design method of heat exchanger networks is improved, the composite curve is divided into several segments for individual treatment, the network of every segment using the uniformity factor of temperature difference of heat exchanger networks as the evaluation index is designed, the structures of every segment and the matches far form the pinch re combined into an integrated original heat exchanger network, the original structure using Newton method as regulation optimization is optimized, and an optimal cost heat exchange network finally is obtained. From a specific example, the heat exchanger network designed according to the uniformity principle of temperature difference field is of better heat transfer performance, the final annual cost is better than that of other literature, and the availability of this method is validated. [ABSTRACT FROM AUTHOR]

Red blood cells are destroyed when the shear stress in the blood pump exceeds a threshold, which in turn triggers hemolysis in the patient. The impeller design of centrifugal blood pumps significantly influences the hydraulic characteristics and hemolytic properties of these devices. Based on this premise, the present study employs a multiphase flow approach to numerically simulate centrifugal blood pumps, investigating the performance of pumps with varying numbers of blades and blade deflection angles. This analysis encompassed the examination of flow field characteristics, hydraulic performance, and hemolytic potential. Numerical results indicated that the concentration of red blood cells and elevated shear stresses primarily occurred at the impeller and volute tongue, which drastically increased the risk of hemolysis in these areas. It was found that increasing the number of blades within a certain range enhanced the hydraulic performance of the pump but also raised the potential for hemolysis. Moreover, augmenting the blade deflection angle could improve the hemolytic performance, particularly in pumps with a higher number of blades. The findings from this study can provide valuable insights for the structural improvement and performance enhancement of centrifugal blood pumps.