Research On Simulation Analysis And Optimization Of Measuring Instrument For Thermal Conductivity Of Asphalt Pavement

Thermal conductivity of asphalt mixture is one of the important parameters in the research of temperature field of asphalt pavement,in the study of the thermal regeneration of the asphalt pavement and rudder prevention,the accurate measurement of the thermal conductivity of asphalt mixture is the premise of the above research in the field.This thesis aims at improving instrument measurement accuracy in the aspect of instrument structure,test technology through research of asphalt mixture thermal conductivity measurement instrument control system in laboratory,combined thermal conductivity test.This article is based on the Project Study on heat transfer mechanism of the infrared continuous heating process of Asphalt Pavement Based on spectral analysis supported by NSFC,combines the measurement principle of the protection plate method and references in domestic and foreign to analyze the source of instrument error.To improvement instrument structure,this thesis simulate the working process of the instrument through ANSYS thermodynamic simulation,using steady-state and transient thermal simulation modules to analyze the heat dissipation of the instrument,and based on the provisions in GB/T 10294-2008 "Determination of Thermal Resistance and Related Characteristics of Thermal Insulation Materials for Protection of Hot Plates".In the aspect of experiment process,the use of thermal silica film to reduce the surface contact thermal resistance of the test piece,and through the test to verify the feasibility of the test process.In the control system,the fuzzy PID control algorithm is used to control the power of the main heating plate of the instrument,and the steady state decision algorithm in the measurement and control system is improved,so that the system can more accurately identify the time point when the instrument enters the steady state.Calibrate the main heating plate power conversion efficiency and temperature sensor.And in the LabVIEW programming environment,the preparation of related measurement procedures to achieve automation of the instrument measurement process.The DRH-VI thermal conductivity meter was used for comparison.The measurement results show that the measurement error of the instrument is within 5%.In the temperature range from room temperature to 80°C,the thermal conductivity coefficient of asphalt mixture was measured.It was found that the thermal conductivity of asphalt mixture increased with the increase of temperature.