ASTM D 341 Viscosity - Temperature Relations For Hydrocarbons

General Form: Loglog𝑍 = 𝐴 – 𝐵 log𝑇                                                                               (Eq. 1)

Where:

𝑍 = (𝑣 + 0.7 + 𝐶 – 𝐷 – 𝐹 + 𝐺 – 𝐻)

Terms C through H are exponentials on the natural base e.

𝑍 = 𝑣 + 0.7 + 𝑒𝑥𝑝(−1.47 − 1.84𝑣 − 0.51𝑣2)                                                                      (Eq. 2)

𝑣 = [𝑍 − 0.7] − exp(−0.7487 − 3.295[𝑍 − 0.7] + 0.6119[𝑍−0.7]² − 0.3193[𝑍−0.7]³          (Eq. 3)

Inserting Eq. 2 into Eq. 1 above, will permit solving for the constants A and B for a fluid in which some of the experimental kinematic viscosity data fall below 2.0 mm2/s (cSt). This form can also be used to calculate the temperature associated with a desired kinematic viscosity.

Conversely, the kinematic viscosity associated with a stated temperature can be found from the equation determined as in Eq. 2 by solving for Z in the substituted Eq 1, and then subsequently deriving the kinematic viscosity from the value of Z using Eq. 3.

Crude Oil Form: Loglog(𝑣 + 0.7) = 𝐴 − 𝐵log𝑇

Where:

𝐴 = log(log(𝑣1 + 0.7)) + 𝐵log𝑇₁

𝐵 = log

𝑣₁ − Kinematic Viscosity cSt (mm²/s) at 𝑇₁

𝑇₁ − Absolute Temperature (K) = (℉ + 273)

𝑣₂ − Kinematic Viscosity cSt (mm²/s) at 𝑇₂

𝑇₂ − Absolute Temperature (K) = (℉ + 273)

𝑣 = 10^{(10𝐴−𝐵log𝑇)} − 0.7

Input Parameters

1. To create a new case, click the “Add Case” button
2. Select the ASTM D 341 Viscosity – Temperature Relations for Hydrocarbons application from the Miscellaneous module list.
3. Enter Case Name, Location, Date and any necessary notes.
4. Fill out all required fields.
5. Make sure the values you are inputting are in the correct units.
6. Click the CALCULATE button.

 

• Select Method
• Product Type
• Temperature (℉ ) (Pair 1)
• Viscosity (cSt) (Pair 1)
• Temperature (℉ ) (Pair 2)
• Viscosity (cSt) (Pair 2)

Outputs/Reports

1. View the results.
2. If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
3. To SAVE, fill out all required case details then click the SAVE button.
4. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
5. To generate a REPORT, click the REPORT button.
6. The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
7. To delete a case, click the DELETE icon near the top of the widget.

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