Study on influence of temperature and pressure in TDLAS trace CO detection

摘要

Tunable Diode Laser Absorption Spectroscopy can achieve high sensitivity, high resolution and non-contact detection of trace gas. But the second harmonic signal will change with the temperature and pressure, resulting a large error in the measurements. Therefore, it is necessary to perform temperature and pressure correction for the measured values. The paper uses two methods of correction to do comparing experiment, one method is polynomial correction and another is BP neural network correction. The experimental results show that the maximum percent error after polynomial correction is 8.01%, while the total percent error after BP Neural network correction is 4.707%. It is obvious that the latter is better than the former on correction effect. The two correction methods all improve the measurement accuracy of CO detection system in varying degree.