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Viscosity of Aviation Fuels

Jet fuels and aviation gasolines used in civil and military aircrafts.

Description

Aviation fuels in general are fuels suitable for use in aircrafts powered by turbojet, turboprop or piston engines. They consist mainly of hydrocarbons (paraffins, cycloparaffins, naphthenes, aromatics and olefins, whereby paraffins and cycloparaffins are the main components. Depending on their specific use they additionally contain additives.

The following aviation fuel types are available:

  • Kerosene - Jet A-1 is the most common type in civil aviation, JP-8 is the military equivalent, TS-1 has improved low-temperature properties. It must fulfill viscosity specifications.
  • Wide-cut fuels: These are a mixture of kerosene and gasoline and can be used in an extended temperature range. Wide-cut fuels must fulfill a density specification, but not all of them must fulfill viscosity specifications.
  • High flash point kerosene: Provides more fire security because of a min. flash point of 60 °C. Must fulfill viscosity specifications.
  • Low volatility kerosene: Gives good thermal stability and contains only a low amount of highly volatile components like toluene or benzene. Must fulfill viscosity specifications.
  • Aviation gasoline: Also known as AVGAS, only for use with piston or Wankel engines. No viscosity specifications.

Low Temperature Scans on Jet Fuels

In order for jet fuel to endure long cold soak periods at temperatures believed to be -40°C or lower, knowing the viscosity of jet fuel at such low temperatures becomes increasingly important. This is especially relevant for so-called Auxiliary Power Units (APUs), which are small gas turbines that need to start up on command. These APUs can be inactive for long periods (15 hours or more) at flying height. During these periods, the fuel's temperature drops down to ambient temperature. The APUs' ability to start depends on the viscosity of the jet fuel at such low temperatures. Too high viscosity prevents fine enough atomization of the jet fuel - consequently, droplet evaporation is not possible.

Data are available for two different jet fuels and a jet fuel reference standard. While fuel JF1107 is type Jet A, fuel JF1411 is type Jet A1. The fuels differ in their freeze point specifications (-40 °C for JET A and -47 °C for Jet A1). Therefore typically viscosity of JET A is higher and JET A also shows a steeper increase of viscosity with decreasing temperatures.

  • Jet A JF1107 was tested as a range scan from -20°C to -55°C with 1°C steps.
    Test duration: 2h 15 min.
  • Jet A1 JF1411 and reference standard Jet N2B were tested as tables scan with variable steps from -20°C to -56°C.
    Test duration: 1h 40 min.

All samples were filled at +20°C. With filling, cleaning and drying at -20°C, which requires a supply of dry air, approximately 15 minutes can be saved.

Viscosity Tables – Measurement data

Jet A/A-1, AVTUR; JP-8, F-34, F-35, AVTUR/FSII (ASTM D 1655, MIL-DTL-83133E)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Kin. Viscosity [mm²/s] Measured Density [g/cm³]
15 0.775 - 0.840
-20 max. 8 4.7704

Jet B (wide cut gasoline type; ASTM D6615)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
15 0.750 - 0.801
- no specification

JP-4, F-40, AVTAG/FSII (wide cut gasoline type; MIL-DTL-5624U)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
15 0.751 - 0.802
- no specification

JP-5, F-44, AVCAT/FSII (high flash point kerosene; MIL-DTL-5624U)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
15 0.788 - 0.845
-20 max. 8.5  

JP-7 (low volatility turbine fuel; MIL-DTL-38219D)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
15 0.779 - 0.806
-20 max. 8

No. 3 Kerosene (GB 6537-2006)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.25 0.775 - 0.830

TS-1 Regular kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.50 min. 0.800
-40 max. 16  

TS-1 Premium kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.30 min. 0.780

T-1 Regular kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.50 min. 0.800
-40 max. 16

T1-S Special kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.50 min. 0.810

T-2 Wide-cut kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.05 min. 0.755
-40 max. 6

RT Premium Kerosene (GOST 10227-86)

Temp. [°C] Kin. Viscosity [mm²/s] Specified Density [g/cm³]
20 min. 1.25 min. 0.775
-40 max. 16  

JET A JF1107 (measured with SVM­™)

Temp. [°C] dyn. viscosity [mPa.s] kin. viscosity [mm²/s] Density [g/cm³]
-20 3.410 4.040 0.8443
-21 3.470 4.110 0.845
-22 3.580 4.230 0.8457
-23 3.690 4.360 0.8464
-24 3.820 4.510 0.8472
-25 3.970 4.680 0.8479
-26 4.130 4.870 0.8486
-27 4.300 5.060 0.8493
-28 4.470 5.260 0.85
-29 4.640 5.460 0.8507
-30 4.810 5.650 0.8514
-31 4.970 5.830 0.8521
-32 5.130 6.020 0.8529
-33 5.300 6.200 0.8536
-34 5.390 6.310 0.8543
-35 5.580 6.530 0.855
-36 5.780 6.750 0.8557
-37 6.000 7.000 0.8565
-38 6.230 7.260 0.8572
-39 6.470 7.550 0.8579
-40 6.740 7.850 0.8586
-41 7.030 8.180 0.8593
-42 7.330 8.530 0.8601
-43 7.660 8.900 0.8608
-44 8.010 9.300 0.8615
-45 8.390 9.730 0.8624
-46 8.800 10.190 0.8631
-47 9.230 10.690 0.8638
-48 9.690 11.210 0.8645
-49 10.200 11.780 0.8652
-50 10.730 12.400 0.8659
-51 11.310 13.050 0.8666
-52 11.940 13.760 0.8673
-53 12.610 14.530 0.868
-54 13.340 15.350 0.8686
-55 14.110 16.230 0.8693

Jet A JF1107 - kinematic / dynamic viscosity and density over temperature

JET A1 JF1411 (measured with SVM™)

Temp. [°C] dyn. viscosity [mPa.s] kin. viscosity [mm²/s] Density [g/cm³]
-20 2.710 3.450 0.7857
-25 3.050 3.870 0.7892
-30 3.560 4.490 0.7928
-35 4.120 5.170 0.7964
-40 4.970 6.210 0.7999
-42 5.390 6.720 0.8014
-44 5.850 7.290 0.8028
-46 6.380 7.930 0.8042
-48 6.960 8.650 0.8056
-50 7.640 9.460 0.8069
-51 8.050 9.960 0.8078
-52 8.460 10.460 0.8085
-53 8.930 11.040 0.8093
-54 9.410 11.620 0.81
-55 9.920 12.240 0.8107
-56 10.490 12.930 0.8114

Jet A1 JF1411 - kinematic / dynamic viscosity and density over temperature

 

Reference Standard Jet N2B (measured with SVM™)

Temp. [°C] dyn. viscosity [mPa.s] kin. viscosity [mm²/s] Density [g/cm³]
-20 7.760 9.290 0.8352
-25 9.520 11.350 0.8387
-30 11.950 14.190 0.8421
-35 15.270 18.050 0.8456
-40 20.060 23.630 0.8491
-42 22.540 26.500 0.8505
-44 25.450 29.880 0.8518
-46 28.950 33.930 0.8532
-48 33.160 38.800 0.8546
-50 38.260 44.700 0.856
-51 41.250 48.150 0.8566
-52 44.590 52.010 0.8573
-53 48.230 56.210 0.858
-54 52.360 60.980 0.8587
-55 56.950 66.280 0.8593
-56 62.240 72.370 0.86

Jet N2B - kinematic / dynamic viscosity and density over temperature

 

Reference

ASTM D1655, ASTM D7566, GOST 10227-86, MIL-DTL-5624U, MIL-DTL-83133E, MIL-DTL-38219D, GB 6537-2006, DEF STAN 91-91 (UK), Measurement SVM™.

Metainformation

Reference ASTM D1655, ASTM D7566, GOST 10227-86, MIL-DTL-5624U, MIL-DTL-83133E, MIL-DTL-38219D, GB 6537-2006, DEF STAN 91-91 (UK), measurement with SVM™.
Kin. vis. yes
Dyn. vis. yes (for JF1107, JF1411, N2B)
Density yes
Multiple temperatures yes
Related Aviation fuel, turbine fuel, jet fuel, jet propellant, kerosene, kinematic viscosity, high flash point jet fuel, low volatility jet fuel, wide-cut jet fuel, AVTUR, AVTAG, AVCAT, AFQRJOS