Color-ratio pyrometry methods for flame–wall impingement study

Abstract

The use of color-ratio pyrometry (CRP) methods, with variable or prescribed soot content (KL) to image flame–wall interactions was examined, with results compared with that obtained using the more mature two-color pyrometry (TCP) technique. The CRP and TCP methods were applied to flame–wall impingement images recorded in a optically-accessible constant volume combustion chamber (CVCC) under compression-ignition (CI) engine conditions. Good correlation in the result trends were observed for the CRP method with fixed KL output and that generated using TCP. Slight discrepancies in the predicted absolute temperature values were observed, which were linked to the difference in the KL value prescribed to the CRP method, and the KL value predicted using TCP. No useful output was obtained with CRP method with variable soot output because of channel noise. A simplified flame transparency modeling was performed to assess the inherent errors associated with the pyrometry methods. The results indicated that the uncertainties arising from the fixing of the KL output appeared acceptable.