| Today,traditional energy sources such as petroleum and fossil fuels are the core resources for global economic development.However,the traditional energy sources currently stored have begun to gradually deplete,and environmental damage is also increasing.In the era of global economic integration,this not only restricts the development of the global economy,but also threatens the future survival and development of humankind.Therefore,developing new energy sources and replacing traditional energy sources with renewable energy sources are important measures to protect the environment and alleviate the energy crisis.Solar energy,as one of the most promising new energy sources,has been used as a research direction for the development of clean and sustainable energy in the world.Solar CSP technology is of great significance for energy conservation and energy heat utilization.Among several current mainstream solar thermal power generation technologies,the Linear Fresnel Reflector(LFR)concentrating system has gradually become a more and more popular method in recent years due to its low cost,high land utilization,and flexible control system.It highlights the research hotspots that global research scholars have paid close attention to.In the LFR system,the concentrated heat collection system mainly provides energy input and focusing for the entire system..The surface energy flow distribution of the heat-absorbing tube in the light-collecting and heat-collecting system is of great significance to study the optical-thermal coupling performance of the system.In the linear Fresnel condensing system,the measurement of the energy flux density of the focused spot on the receiver surface is a very important task.It is not only a main parameter for evaluating the performance of the condensing system,but also an optimized tracking control system and system mirror field Important indicators.Based on the idea of photographic energy flow(PHLUX)method and image processing,this paper proposes a new method for measuring the uniformity of the focused spot energy flow on the surface of the collector tube at the opening plane of the secondary condenser of the linear Fresnel thermal power generation system.This detection method is based on a CCD camera and a dual Lambertian target for measuring the energy flow uniformity of a system and method.The system has two Lambertian targets,one of which is a fixed water-cooled Lambertian target,and an energy flow detector for obtaining the regional gray value is installed at the center opening of the target,and the other is a movable Lambertian target for Take a spot image without an energy flow detector.This measurement method can directly obtain the pixel gray value of the detector area,making the measurement process simple and accurate.The measurement principle and the entire process of extracting the energy flow density distribution of the gray image of the focused spot are described in detail.By setting up an experimental platform and measuring the focused spot energy flow of a multi-faceted small heliostat,repeatability experiments and error analysis of the system were performed to verify the correctness and feasibility of the method.The verification results show that the peak energy flow density error detected by this method is less than 2.8%.The detection method has a relatively small measurement error.It can measure both solar thermal power generation systems with small concentration ratios such as linear Fresnel reflection,and can also be used to measure the spot energy flow of solar thermal power generation systems with large concentration ratios(such as towers).Uniformity detection.In this paper,the characteristics of the energy flow density distribution on the surface of the linear Fresnel receiver are analyzed and found.Due to the structural characteristics of the LFR system itself,this non-uniform energy flow distribution on the upper and lower surfaces of the collector tube of the concentrating system is inevitable.The lower surface of the heat collecting tube is the direct light-concentrating area of the system,and the high heat energy reflected by the primary mirror to this area will generate greater thermal stress,while the upper surface of the heat collecting tube under the CPC receives only a small amount of light,so this area is distributed The energy flow is low,so the entire surface of the collector tube has a greatly different energy flow distribution.If the high energy flow distributed in the direct concentrating area is not optimized in time,the large thermal stress generated on the surface of the heat collecting tube will burn the wall of the heat collecting tube and adversely affect the safe and stable operation of the system.To solve this problem,this paper proposes an optimization method of multi-objective optimization algorithm based on genetic algorithm.The core idea of this method is to optimize the energy flow distribution on the receiver surface by changing the line of sight of each mirror surface of the primary mirror of the LFR system.The specific method is to optimize the aiming point of each primary mirror surface in the main mirror field of the entire system,so that the standard deviation of the energy flow density distribution on the surface of the heat collecting tube becomes smaller.The simulation results using the optimization algorithm show that after the optimization algorithm optimizes the LFR system,the optical efficiency of the system increases from 62.83% to 78.15%,and the efficiency increase is close to 16%.This method not only optimizes the non-uniform flux distribution on the surface of the heat collecting tube,but also ensures a good optical efficiency of the system. |
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