| Combustion temperature testing technique is one of the important foundations in combustion theory and technique developing. The temperature field of flame in the hearth has epochmaking meaning as for controlling the boiler and diagnosing combustion. As a new-style temperature measuring method, the acoustic method is much faster and with a high precision as well as a broader measuring range. It can satisfy the requirements of measuring accurately and controlling online on the temperature field in industrial productions and scientific investigations. It has important instructional meaning for optimizing combustion, reducing pollution, equipment circulating safely and designing the hearth.The principle and the common techniques of temperature field measurement are introduced in this thesis. By using acoustic sensors, the reconstruction and emulation of temperature fields in a coal fired boiler was studied. Two planes along the boiler axial are selected and the 3D temperature field surrounded by the two planes was reconstructed. Eight acoustic sensors were installed symmetrically on each plane and the sound emitted by any one of them could be received by the others. Based on the measurement of flight time of acoustic waves travelling between acoustic sensors and by using least square root, the 3D temperature fields of the Single-peak symmetry temperature field, the Single-peak asymmetry temperature field and the Double-peak temperature field were reconstructed.Aimed at the typical symmetrical temperature distribution in furnace, the algorithm of reconstruction by used a single path temperature function firstly, then plotted the grid and interpolated is proposed. But this method has limited in a certain extent which has better reconstructed effect for Single-peak symmetry temperature field. Finally, a good many of elements which may affect the precision of temperature field reconstruction were summarized. Correlative improvements were attached. |
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