Thermal Decomposition Kinetics of the Thermally Stable Jet Fuels JP-7, JP-TS and JP-900

Abstract

The thermal decomposition kinetics of JP-7, JP-TS and JP-900 were studied, motivated by the need of the hypersonic vehicle community for a fuel that has a high degree of thermal stability. Decomposition reactions were performed at 375, 400, 425 and 450 °C in stainless-steel ampule reactors. In all cases, the pressure before decomposition was 34.5 MPa (5000 psi). Decomposition as a function of time at each temperature was quantified by analyzing the thermally stressed liquid phase using gas chromatography. These results were used to determine global first-order rate constants that approximate the overall decomposition rate of of each fuel. For JP-7, these first-order rate constants ranged from 1.79 × 10 −5 s −1 at 375 °C to 3.02 × 10 −4 s −1 at 450 °C. For JP-TS, the rate constants had values between 1.74 × 10 −5 s −1 at 375 °C to 2.70 × 10 −4 s −1 at 450 °C. For JP-900, the rate constants ranged from 1.03 × 10 −5 s −1 at 375 °C to 3.60 × 10 −4 s −1 at 450 °C. At all temperatures studied, these three fuels have similar rate constants for thermal decomposition; with only one exception, the values of k′ are identical within the combined uncertainty. The rate constants for the decomposition of RP-2, a fuel being considered as a replacement fuel for hypersonic vehicles, are similar in the temperature range studied. Considering the time needed for 1% of the sample to decompose (t 0.01 ), we find that required instrument residence times range from 16 min at 375 °C to 30 s at 450 °C. The rate constants measured here, as well as the Arrhenius parameters that we calculate, can be used to design and plan physical property measurements at additional temperatures.

Thermal Decomposition Kinetics of Polyol Ester Lubricants

“…The age of the ampule cell was also shown to be important for test repeatability, indicating that surface reactions are able to influence the decomposition rates of the polyol esters. This is contrary to previous decomposition studies using the ampule reactors to heat (unoxygenated) hydrocarbon fuels. ,− These previous experiments showed no correlation between cell age and measured decomposition rate. However, heating the pure polyol ester base oils in new, unpassivated cells resulted in decomposition products formed at a faster rate than use of an older cell heated under exactly the same conditions.…”

“…The thermal decomposition measurements are performed in stainless steel ampule reactors, and the extent of decomposition, as a function of time, is determined by gas chromatography with flame ionization detection (GC-FID). Similar measurements have been performed on pure fluids and fuel mixtures − employing this strategy. From these measurements, rate constants and ultimately Arrhenius parameters can be determined, which provides a guide for the subsequent property measurements and in-service constraints.…”

“…After heating, the thermally decomposed liquid sample was removed from the cell in two steps. Some reaction conditions produced volatile species, which caused the final cell pressure to increase . In order to minimize sample loss, a short piece of bent tubing was secured to the valve and directed into a 2 mL autosampler vial to collect any expelled liquid.…”

Regioselective Synthesis of Methyl-Substituted Adamantanes for Promoting Oxidation Stability of High-Density Fuels

“…Since aerospace vehicles (like missiles and rockets) are always volume-limited, high density of fuels becomes the principal determining factor of flight range and payload. − Meanwhile, future supersonic and hypersonic aircraft engines will encounter more aerodynamic heating than current engines. Thus, jet fuel will serve the dual role as a propellant to provide propulsion energy and as a coolant to circulate through the airframe and engine components to remove extra heat. − Under these conditions, the fuel will experience huge thermal stress. Unfortunately, conventional high-density fuel is highly susceptible to oxidative degradation.…”

High-Pressure Thermal Decomposition of Tetrahydrotricyclopentadiene (THTCPD) and Binary High-Density Hydrocarbon Fuels of JP-10/THTCPD in a Tubular Flowing Reactor

“…The conversion of THTCPD was defined as follows: ,− The overall conversion of JP-10/THTCPD was defined as follows: where m l and m 0 were the mass of liquid phase and feed fuel during the same time, respectively. w li and w 0 i were the THTCPD mass fraction of liquid phase and feed fuel, respectively.…”