Constant volume combustion chamber (CVCC) investigations of aerospace F-24 and Jet-A in low-temperature heat release and negative temperature coefficient regions

Abstract

A study was conducted to determine the characteristics of Low Temperature Heat Release, Derived Cetane Number, and the Vibrations, produced by the combustion of aerospace F24 using Jet-A as a baseline in a Constant Volume Combustion Chamber. The Ignition Delay and Combustion Delay for F-24 were found to be 4.04 ms and 5.71 ms with a DCN resulting at 43.77. Jet-A was found to have a larger DCN of 47 with an ignition delay and combustion delay of 3.35 ms and 5.14 ms. F24 has an extended region of cool flame and releases more of its energy during LTHR than Jet-A, however has a much shorter NTCR than that of Jet-A. From the NVH analysis it was found that there exists a strong correlation between the ID and CD phases and their respective NVH spectrum. It was found that the magnitude of the ringing for Jet-A was 3x higher than that of F24. Meanwhile, the magnitude of vibrations produced by Jet A was approximately 0.5 g greater than those produced by F24′s combustion which correlates well with the higher peak value of AHRR for Jet A and also with higher ringing produced by Jet A compared with F24.