Numerical Investigation Of Particle Flow And Heat Transfer Characteristics In A Tube Solar Receiver

As a clean and renewable energy source,solar energy has a wide application prospect in the future industrial production and people's daily life.Concentrating Solar Power(CSP)is a typical technology that uses solar energy to generate electricity on a large scale.Among several common CSP systems,the Solar Power Tower system has high power generation efficiency due to its suitability for working in a higher temperature range,and the use of particles as a heat transfer fluid(HTF)helps to increase the operating temperature of the Solar Power Tower.The continuous development of solar particle receiver has thus become a trend.This paper mainly focuses on the Solar Power Tower system and considers a solar energy solid particle receiver with a built-in heating tube array.Different from the solid particle receiver(SPR)proposed earlier,this type of receiver is a new type of solar receiver proposed in recent years.Due to the difficulties in performing large-scale thermal experiments on CSP,numerical simulation methods are mainly used for research.Currently,some scholars use the DEM method to calculate this process,but this method has a large amount of calculation.Some scholars also use open-source code for self-programming calculations.Although this method is suitable for mechanism research,it is inconvenient for a large number of solar receivers to be optimally designed.In contrast,the two-fluid method has certain advantages.This paper uses CFD-TFM method to optimize the design of the new solar energy solid particle receiver.Four different shapes of heating tube array receivers were selected,and each receiver was calculated under the conditions of changing the particle inlet velocity.For the same receiver,the overall heat transfer coefficient at different particle inlet velocities is analyzed.It can be concluded that the overall heat transfer coefficient continuously increases with the increase of particle inlet velocity in a certain range,and the heat transfer performance is continuously obtained improvement.By analyzing the overall heat transfer coefficient of different tubular receivers under the same working conditions,the results show that as the particle inlet velocity constantly changes,the relative relationship between the overall heat transfer coefficient of each tube shape is also constantly changing.However,it can be clearly seen that as the particle inlet velocity increases,the overall heat transfer coefficient of the rectangle tube receiver gradually increases,eventually higher than the other three tube shapedreceivers.This shows that the overall heat transfer performance of the rectangle tube receiver is better.In order to eliminate the effect of the piping method,the spacing between pipes was also adjusted.The results show that the pipe spacing does not have a significant impact on the optimization conclusions.Based on the optimization results,continue to explore the radiation characteristics.Raise the temperature of the wall of the heating tube in the rectangle tube receiver,and add the radiation model at different temperatures.For the radiation model,DO(Discrete Ordinates)model and P1 model are used.The analysis of the calculation results shows that as the temperature of the pipe wall increases,the proportion of radiative heat transfer to total heat transfer increases.At the same time,in addition to the need to consider the optical thickness of the radiation model,the specific temperature range must also be considered.