Numerical and experimental study on temperature field reconstruction based on acoustic tomography

Obtaining a high-quality measurement of the temperature distribution is crucial to optimally adjust the combustion in a boiler. Acoustic tomography (AT) can be used to measure the temperature distribution from multipath acoustic time of flight (TOF). The reconstructed model and TOF measurement are crucial for practical applications of AT measurement. In this paper, a new temperature field reconstruction model based on radial basis function approximation with polynomial reproduction is presented for solving the AT inverse problem. In our reconstructed model, we also consider the refraction effect of sound wave paths in the non-uniform temperature field. A truncated singular value decomposition reconstruction method is used to improve the reconstruction quality and the anti-noise ability. In addition, a generalized cross-correlation with second correlation is applied to estimate the TOF to effectively suppress interference from noise. Numerical simulations and experimental study are implemented to evaluate the effectiveness of the proposed reconstruction method. The numerical results indicate that our model considering the refraction effect can reconstruct temperature distributions with higher accuracy and better anti-noise ability compared with other existing methods. The experimental results are compared against thermocouple measurements, which show that when considering the refraction effect, the proposed method has superior reconstruction performance than methods without the refraction effect.