Optimization of Multi-zone Cooling System of Complex Pipe Network Based on Particle Swarm and Genetic Algorithm

The cooling pipe network system of the power plant has the characteristics of multiple users, multiple working conditions, and complex topological structure. The division of water supply to the pipe network can simplify the topological structure of the pipe network, facilitate flow regulation, and adapt to the requirements of multiple working conditions. District water supply can be divided into districts according to flow, pressure and structure. The user allocation of pipe network water supply system is a typical combined optimization problem. When the system is relatively complex and the number of users is huge, conventional enumeration methods, dynamic programming and other methods are often unable to solve such problems. The combined algorithm of particle swarm algorithm and genetic algorithm can obtain approximate solutions to such problems. By using a combination of particle swarm algorithm and genetic algorithm to analyze and determine the distribution of pipe network user traffic, it is possible to avoid the waste of energy in the distribution of pipe network users based on experience. The combined algorithm proposed in this paper has high stability, can change the number of partitions to adjust user allocation according to actual needs, and has strong versatility. For the case described in this article, when the number of partitions is 2, compared to the cases where the number of partitions is 3 and 4, the flow rate and pressure drop of each partition are not much different, which can better meet the reliability and maintainability requirement

Research on Locally Resonant Characteristics of Pipelines with Periodic Structure

In this paper, the propagation characteristics of vibration waves in periodic pipelines were studied based on the band theory of phononic crystals, and we analyzed the influence of the geometrical structure parameters on the band gap characteristics of pipelines. The results show that, by increasing the number of layers of local resonant structure, both the initial frequency and the cutoff frequency of the band gap moved towards the lower frequency, while the width of the system band gap increased by 35 Hz, and the damping effect increased by 18.3 dB. By changing the thickness of the wall of the pipeline system, the width of the system band gap increased by 20 Hz, and the damping effect increased by 9.1 dB. The maximum vibration isolation of the offshore platform truss based on the periodic structure can be up to 7.93 dB. Therefore, it is feasible to apply the local resonant periodic structure to the vibration control of a practical offshore platform

Research on Dynamic Modeling of the Supercritical Carbon Dioxide Power Cycle

The supercritical carbon dioxide (SCO2) Brayton cycle, as a substitute for the steam cycle, can be widely used in a variety of power generation scenarios. However, most of the existing SCO2 cycle studies are restricted to basic thermodynamics research, parameter optimizations, system design in different application fields, and even economic analysis. Considering the load variability and control flexibility of the power generation system, the dynamic performance research of the SCO2 cycle is also crucial, but the work done is still limited. Based on the previous studies, Simulink software is used in this paper to develop a dynamic model of the 20 MW-SCO2 recompression cycle, which specifically includes component models that can independently realize physical functions and an overall closed-loop cycle model. A series of comparative calculation are carried out to verify the models and the results are very positive. The SCO2 recompression power system is built with the developed models and the dynamic model runs stably with a maximum error of 0.56%. Finally, the simulation of the dynamic switching conditions of the 20 MW-SCO2 recompression cycle are performed and the analysis results supply instructive suggestions for the system operation and control