Studying And Designing A Device For The Thermal Performance Testing Of Phase Change Heat Pipe

Miniature spacecrafts (microsatellite) are on the way ofminiaturization, lightweight and intelligence, which requires all theinstruments on the satellite to be highly integrated and small. Therequirements have led to the instruments’ high heat flux and hightemperature. So, heat emission problem of the local high heat fluxbecomes the most important issue to be solved of the satellite thermalcontrol. In the satellite thermal control, phase change heat pipe iscommonly used for cooling heated devices to control the temperature leveland improve the uniformity of the satellite’s temperature field. Therefore,researching the thermal performance of phase change heat pipe is of greatsignificance. In this dissertation, in order to obtain parameters about thethermal performance of the phase change heat pipe, a device had beendesigned, which was used for testing the thermal performance of phasechange heat pipe. The main work was as follows:The experimental table had been designed by SolidWorks, whichcould accommodate10phase change heat pipes with different lengths of200mm~1500mm and could adjust the horizontality of the phase changeheat pipe. Designed the electrical control system and completed the wiringand installation of the control cabinet, which included power board, sensorboard, thermocouple measurement board and the control board.In order to meet the high precise control requirement of the variablepower heating system, variable power PID control system had beendesigned and achieved precise control of the power under different heatingpower. The main work was as follows: the design of hardware system,including the selection and analysis of the voltage sensor, current sensor and controllable DC power; the development of software system, includingthe voltage and current monitoring and the realization of PID algorithm.In order to meet the condensation section’s constant temperaturerequirement of phase change heat pipe under different heating power,cooling temperature control system had been designed, which achieved theprecise temperature control of the condensation section through controllingthe coolant flow rate by the PWM technique. The main work was asfollows: the design and selection of refrigerator and cold plate; the remotecontrol of Agilent34980A temperature measurement system in LabVIEW;the design of temperature segmented controller. Because the temperaturecontrol system had the characteristics of large disturbance, large time delayand nonlinear, a multi-mode segmented control algorithm was proposed,which combined Bang-Bang control, fuzzy control and human-simulatedintelligent control. Two critical points were proposed. One was that thebasic fuzzy control was changed into incremental fuzzy control. The otherwas that the change rate of error was taken as a control object ofhuman-simulated control. The precise temperature control was achievedand the algorithm was very effective through experimental verification.The entire software system was developed in LabVIEW and theinterfaces of LabVIEW were designed. The main functions of the softwaresystem consisted of the acquisition, preservation and display of voltage,current and temperature; user management system, data managementsystem, parameter setting and over temperature alarm protection.The entire test device functioned very well in the practicalengineering application and the segmented control algorithm was veryreasonable. The research was very meaningful in the aspect of engineering.