| With the continuous consumption of non-renewable resources and the increasing research into green energy,As a kind of green energy with great potential,more and more people pay attention to microalgae.With the development of LED technology,LEDs are widely used in lighting,projection,horticulture,etc.The many advantages of LEDs make them an attractive choice for the cultivation of microalgae.With the development of LED technology,LEDs are widely used in lighting,projection,gardening,etc.Among the many cultivation methods of cultivating microalgae,The photobioreactor has unique advantages.However,in practice,due to the different distances between LEDs and the size of the irradiation plane,the light intensity in the irradiation plane is not uniform,which makes it impossible to guarantee the quality of microalgae culture.This paper focuses on optimising the distances of the LED arrays using an improved PSO algorithm to improve the uniformity of the light intensity of the LED arrays,which is verified by simulation and practical experiments.The relationship between the LED temperature with the size of the aluminium substrate and the pitch of the LED is also experimentally studied,providing a direction for the design of thermal management of LEDs.The main content of this article is as follows:Firstly,Introduces photobioreactors for microalgae culture,the development history of LED,the research status of LED illumination uniformity in different fields,and determined the research method suitable for application in photobioreactor.Secondly,Knowledge about LEDs,including their structure,luminescence principles,relevant lighting terminology including luminous flux,etc.,is introduced,as well as knowledge about the thermal properties of LEDs.Knowledge of the thermal properties of LEDs,including the causes of junction temperature,the effects of junction temperature on LEDs and ways to reduce junction temperature,is also presented.The concept of LED thermal resistance,a simple LED thermal resistance model is introduced.The relationship between LED voltage and luminous flux,temperature and luminous efficiency is investigated,and the best working conditions for LEDs are obtained,providing a basis for the optimised design of LED arrays.Thirdly,From the illumination model of a single LED,we derived the average expression for the illumination intensity of n LEDs in the irradiation plane,as well as the standard deviation of the illumination intensity;and used this as an evaluation function to optimise the LED pitch using an improved particle swarm algorithm.The results of the optimisation are compared with the uniformity of the comparative array using the optical software Trace Pro to simulate the uniformity of the illumination intensity.Fourthly,Experimentally verify the optimised LED arrays and investigate the effects of different sizes of aluminium substrates and the distance between LEDs on LED heat dissipation.The uniformity of the light intensity of the LED array designed by the optimized algorithm is better than that of the comparison array,and the related experiments on the thermal characteristics of LEDs also provide directions for the heat dissipation treatment of LED devices. |
