Traditional stage-wised superstructure (SWS) of heat exchanger network allowes that utilities are placed at ends of process streams, which restricts flexible development of network structures. Hence, a novel inner utility placement strategy is proposed, in which utilities could be placed at each stream branch in intermediate stages. An improved random walk algorithm with compulsive evolution with structure-protection strategy (SP-RWCE) is employed, in which a pseudo optimum generation strategy is presented to modify SP-RWCE, where pseudo optimums with evolution potentialities could be promoted and generated to accept protection and exploitation by expanding optimal total annual cost of individuals in long-term evolution stagnation. Optimization results of three benchmark cases are superior to reported values, all of them include inner utilities. It indicates that the modified SWS enlarges solution space, the improved SP-RWCE has stronger search ability, and the placement of inner utility could effectively reduce heat exchange areas.

Thermonuclear reaction rate describing thermonuclear burning efficiency in thermonuclear fusion is studied.As one species atomic nucleus with Maxwell velocity distribution,another species atomic nucleus velocity is divided into several groups.Velocity group thermonuclear reaction rate and averaged thermonuclear reaction rate are deduced,and simulation codes are obtained.Taking deuterium-tritium thermonuclear fusion reaction as an example,velocity group thermonuclear reaction rates and corresponding averaged thermonuclear reaction rates are calculated and analyzed comparing with exact direct integration results.Finally,relation between averaged thermonuclear reaction rate and velocity group number is studied.