Abstract
Low-resolution nuclear magnetic resonance is a tool that has been employed for many years as an effective method for analyzing complex materials in a non-destructive fashion. This work has been aimed at the development of a prototype compact NMR system with the potential to be utilized for simple and rapid in situ measurements of key properties of jet fuels. The compact system consists of a neodymium magnet configuration with a field strength of 0.645 T, custom printed circuit boards, and radio frequency electronics. It is driven by a National Instruments PXI chassis fitted with modules that control the excitation and detection of hydrogen proton resonance in various samples. The current system is suitable for transverse relaxation (T2) studies using the Carr-Purcell-Meiboom-Gill pulse sequence, as it can produce relaxation curves containing thousands of spin echoes. Determination of hydrogen content (mass %), which is strongly correlated to combustion properties of fuels, is the primary area of interest for this study. Utilizing an array of 16 reference samples, a direct correlation between initial signal amplitude and hydrogen density (kmol/m3) was established. This relationship, along with mass density measurements, was used to determine hydrogen content in six different jet fuels. The maximum error between measured and accepted values for the fuels was 0.7%.
