Research On Flux Distribution Simulation And Focus Strategy Of TSP Plant

The solar radiation is reflected and gathered by a certain number of heliostats to the aperture of one or more receivers to form high-temperature steam in an associated thermodynamic process to promote the turbine power generation in a solar power tower plant. It has the advantage of big concentrating ratio and high operation temperature. As one part of the concentrating system, the heat receiver undertakes the crucial work of photothermal conversion. Since the image simulation directly reflects the flux distribution of the receiver surface, which is helpful to the design and operation of the whole plant, it is significant in the solar tower power system.So the imaging and the focus strategy are studied in the thesis. The main contributions of this thesis are as follows.The non-parallel incident rays are generated according to the divergence of the sunlight, which means each incident ray has an angle(solar angle) subtended between the center of the sun to some point toward the edge. It makes the simulation of the flux distribution more practical and accurate. Meanwhile, the physical distribution model and the energy conversion model are built to analyze the components of the optical efficiency and their influence on image.Monte Carlo Ray Tracing Algorithm is introduced and used here to obtain the simulation image of single heliostat and heliostat fields respectively. The simulation results are verified by the comparison with the actual data. Also, the influence of different field parameters on image is analyzed.Graphic Processing Unit(GPU) parallel computing and Compute Unified Device Architec-ture(CUDA) platform is used to accelerate the ray tracing program. The eSolar Plant in Lancaster is taken as an example to describe the optimization steps of the parallel process. It shows that the computational efficiency has been improved significantly under GPU.Based on the simulation model and GPU parallel codes, the optimization model of the heat receiver is proposed on the premise of security problem. Maximum utilization of solar energy can be guaranteed under the situation where the flux peak is no more than the heat-durability power of the pipes. And, the comparison between the simulation results for different time and the different number of aim points are discussed.In summary, the flux distribution of the receiver surface is obtained by Monte Carlo ray tracing method based on GPU parallel computing and CUDA platform and the optimization model with multiple aim points is developed to ensure the maximum solar energy usage as well as the safe operation of the heat receiver. The work in this thesis can provide the foundation for receiver design and field scheduling.