Optimization Experiment of T-TDR Sensor Thermocouple Node Positions

Abstract:

In order to improve the measurement accuracy of T-TDR sensor and optimize its structure parameters, the rules of the thermocouple node embedded positions and size to its sensitivity and accuracy were studied. Based on the node in the probe middle, midpoint moving down 2mm and reducing the volume thermocouple nodes by spot welding, three kinds of T-TDR sensors and their measuring system were designed. The five different water content of each sandy, sandy loam and clay loam were tested to measure the thermal characteristic curves and calculate its water content. Oven drying method was used to test accuracy. The results showed that the thermocouple on the probe midpoint moving down 2mm and spot welding junction was more sensitive to the radiant heat of the 〖JP3〗intermediate probe than the other sensors. The measurement value of moisture content had good correlation (R2 of 0.981, RMSE of 0.0152) between drying method. The measurement accuracy was higher than traditional structural parameters.