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Equation for conductivity value of organic liquids

Equation for conductivity value of organic liquids

Equation for conductivity value of organic liquids

(OP)
Dear friends,

To calculate thermal conductivity value of organic liquids I found the following formulae in April 12,1975 issue of Chemical Engineering. Is it can be used to calculate thermal conductivity value of  SAE 10W  oil.

K =0.000877 x Density^(0.83) x (293/T)^(0.38) Cal/(s-cm- °C)
Cp in (CAL/Gm/°C)
Density in (gm/cc)
T in °K in absolute

Please advise. Thanks in advance.

RE: Equation for conductivity value of organic liquids

The API Technical Data Book - Petroleum Refining (chapter 12, 1980) presents Procedure 12A3.1 for conductivity of petroleum fractions of unknown composition, at low pressures:
 k= 0.07727 -(4.558E-5)*T
where T is Fahrenheit and k is BTU/ft-hr-F. Average error is said to be 10%, with maximum error 40%. This was a best fit of data from five sources. In 1997, Chapter 12 was revised to improve the accuracy of the above equation form slightly, to 6% average, 24% maximum. They also added a procedure to use when the mean average boiling point of the fraction is known.

RE: Equation for conductivity value of organic liquids

From "Engineering Tribology" (Elsevier) by Stachowiak and Batchelor, the thermal conductivity of mineral and synthetic hydrocarbon based lubricants is in the range of between 0.14  W/mK @ 0oC to 0.11 W/mK @ 400oC. For a rough estimation of a thermal conductivity the following formula has been suggested:

K = (0.12/s)(1-0.0001667 T)

K = conductivity, W/mK
s = specific gravity @ 60 deg F
T = temperature, deg C.

It is apparent that an exact value cannot be found. It is also difficult to know what is the effect the additives have on a 10W oil.

If one selects a formula and sticks to it, one's systematic errors will then not change much. It wouldn't be practical to express results with more than two significant figures.

RE: Equation for conductivity value of organic liquids

(OP)
Dear DickRussell and 25362,

Thanks to both of you.I have an STHE data sheet with SAE 10W  oil on S/S. K Value is not given in the data sheet. I try the design with K from these two formulas.

Thanks once again.

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