Study On Temperature And Humidity Control Of Optical Elements In Airfield Runway Foreign Object Debris Detection System

With the rapid development of civil aviation in China,the number of flights is increasing day by day.At the same time,the airport runway is becoming more and more efficient,and the security of the runway is becoming more and more important.An effective solution to this security problem is the airport runway foreign body detection system.In order to make the system serving for airport runway security better,this paper studies the internal temperature and humidity control of its optical detection turntable.The design and analysis of the outer sunshade of the optical detection platform are carried out by means of numerical simulation.The system design and experimental analysis of the temperature and humidity control of the inner space of the turntable are carried out.Firstly,the outer sunshade of the optical detection platform is designed preliminary based on the conditions of airport height limits.While the height,width and opening size of the hood are limited,the ventilation cooling effect is founded better when the back of sun shade is 0.3 meters behind the table and it is opened on the left,right and back by comparing the steady-state numerical simulation under certain environmental conditions.The shading effect of sunshade hood was analyzed from temperature change,hourly temperature field and heat transfer by unsteady numerical simulation.After the shading: The changes of average temperature and the rate of change of the average temperature in the cavity were significantly decreased.The maximum temperature of air and tube in the cavity is decreased,and the maximum temperature difference of air is greatly reduced.The temperature distribution in the cavity became uniform and the high temperature area decreased significantly.The heat absorption of the shell and the tube was reduced by 30%.Next,the active control system of the internal cavity temperature humidity control of the optical detection turntable is designed,selects the wall radiation heat transfer in combination with reinforced convection and solid desiccant as the temperature and humidity control scheme,the function mechanism of surface radiation and prevent condensation issue is analyzed.Finally,by making a turntable simplified model of the same size and material,setting up high and low temperature experimental platform,experiments and analysis of the temperature control effect of active control system for the working condition of winter and summer is carried out.In the winter conditions,the temperature control of the tube,the temperature difference between each point in the cavity and the temperature control strategyare studied.Concluded that: 1)when around tube inlet temperature was set to 40? and30?,the latter can achieve better control effect;2)when the around tube inlet temperature was set to 30?,by increasing the micro DC fan reinforcement to strengthen the circulation of heat and air circulation,temperature difference between each point can be reduced from2? to 1.2?;3)It can make the cavity in the body temperature quickly reaching a new equilibrium and small variations in temperature with the air temperature in the body cavity and temperature gradient as a parameter to monitor,control air temperature gradient within the scope of the requirements;The control strategy of controlling the water inlet temperature of the tube can achieve the control requirements under the experimental conditions of this paper,while its control is simpler and its energy consumption is smaller.Under the condition of summer,the effect of flow velocity on temperature inside the cavity was studied,and the control effect with the hourly solar radiation and the most adverse temperature environment was studied.The experimental results show that : 1)The fluid velocity has little influence on temperature inside the cavity.2)When the summer temperatures hourly changed and there is direct sunlight on glass window at sunrise and sunset,under the condition of extreme high temperature of 54? and environmental temperature change sharply,the system can satisfy the requirement of the cavity internal temperature control.