Test Method for Kinematic Viscosity of Liquid Petroleum Products
Petroleum products refer to a general term for various commodities produced from petroleum or natural gas through refining and chemical processing, mainly including six categories: fuels, solvents, lubricating oils, paraffin wax, asphalt and petroleum coke. Among them, fuel products (such as gasoline and diesel) account for about 90%, while lubricants have the most diverse varieties. These products are widely used in transportation, industry and daily life fields.
Purpose of the Experiment：
1.Evaluate flow performance: By quantifying internal friction, determine the performance of oil products in practical applications such as transportation and atomization.
2.Quality control: As a key indicator for products like lubricating oils and fuels, ensure compliance with industry standards.
3.Process optimization: Provide data support for petroleum processing and equipment lubrication schemes, avoiding energy consumption or wear issues caused by viscosity mismatch.
4.Scientific research foundation: Supply rheological property parameters for material research and development (e.g., polymers and coatings).
Experimental Instruments & Samples：
Experimental Sample: Petroleum Products
Experimental Instrument: SD265D Petroleum Kinematic Viscometer (Dual-cylinder), compliant with ASTM D445.
Testing method：
1. Sample Preparation
If the sample contains moisture or impurities, dehydration and filtration are required (e.g., using filter paper or a porcelain funnel).
The viscometer shall be cleaned with solvent oil; if necessary, it shall be rinsed with chromic acid cleaning solution and dried.
2. Sample Loading & Temperature Equilibration
Draw the sample into the viscometer up to the marked line to avoid bubble formation.
Immerse the viscometer vertically in the constant-temperature bath. The equilibration time shall be determined according to the temperature (e.g., 10 minutes at 20℃ and 20 minutes at 100℃).
3. Determination of Flow Time
Start the stopwatch when the liquid level passes the marked line a, and stop it when the liquid level reaches the marked line.
Repeat the measurement at least 4 times. The deviation of flow time shall meet the requirements (e.g., ≤ ±0.5% at 100–15℃).
4. Calculation of Kinematic Viscosity
Formula: ν=C×t
Where:C = viscometer constant；t = average flow time；
Unit: mm ² /s(centistokes, cSt)
Experimental Results：
The kinematic viscosity of this petroleum product at 40℃ is 835 cSt, which meets the requirements of the GB/T 265-88 standard. It is suitable for lubricating oil grade classification and flow performance evaluation.