- Method ASTM D3241
- Repeatability None Established
- Reproducibility None Established
- Blending non-linear
- Additive Correction Yes
The purpose of this test is for measuring the high temperature stability of gas turbine fuels. The method works by introducing oxygen to the fuel and then subjects it to high pressures and temperatures in order to duplicate conditions inside a turbine engine. Deposits formed on the tube are then rated on a color chart to indicate whether it is passing or failing. The scale ranges from 0 to 4. There is new technology out now that will measure the thickness of the deposits on the tube. This is quickly becoming the system of rating that is preferred. The data gathered in this test is essential selecting quality fuels that will not foul up the turbine or filters.
The method is performed by filtering the sample into a beaker that is then aerated. While this is being done a JFTOT tube is installed into the instrument with a new filter. Once the aeration is complete the run is started. The JFTOT tube will begin to heat to a temperature of 260°C or 275°C (depending upon spec) and the high pressure pump will begin to pressurize the sample.
The sample is then pumped through the filter and over the JFTOT tube for approximately 2.5 hours. Once complete the tube is removed and rated visually or with the use of a tube reader.