A single-path LAS fused electrical capacitance tomography for flame temperature imaging

Abstract A single-path laser absorption spectroscopy (LAS) is fused to enable electrical capacitance tomography (ECT) for quantitative imaging of flame gas temperatures. A temperature histogram is achieved along a single path from LAS, while permittivity values along the same path are obtained via using the Calderon method in ECT. In the case of dynamic flames, these histograms vary over time. An online mapping from permittivity histograms to temperature histograms is constructed via a modified Transformer model. Permittivity histograms of more virtual laser paths are derived from the ECT images of permittivity and mapping. Temperature histograms along these paths are achieved from the mapping and permittivity histograms. Temperature distributions are reconstructed from these temperature histograms and enable a quantitative imaging of gas temperature from only a single-path LAS, which is regarded to have no spatial resolution along the path. A self—pressurized alcohol lamp was used in experiments of flame imaging. In addition, a compact sensor for both LAS tomography and ECT was used to monitor alcohol lamp flames to verify the proposed method. LAS tomography was utilized to reconstruct the temperature, and the mean temperature relative deviation is less than 5% for 90% cases of the measured samples, with a maximum relative deviation of 7.46%.