SH/T 0703-2001 Standard test method for measuring apparent viscosity of lubricating oils at high temperature and high shear rate (multiple capillary viscometer method)

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Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0703—2001
• Chinese name: Standard test method for measuring apparent viscosity of lubricating oils at high temperature and high shear rate (multiple capillary viscometer method)
• English name: Standard test method for measuring apparent viscosity at high-temperature and high-shear rate by multicell capillary viscometer (the original title page is spelled as "texnperature…rnlticell capilary", requires confirmation against the source standard (source-text extraction))
• Replacement relationship: not provided in the available source (the foreword only states equivalent adoption of ASTM D5481—96, and does not mention replacement of an old standard)
• Adoption relationship: equivalent adoption of ASTM D5481—96 "Standard test method for measuring apparent viscosity of lubricating oils at high temperature and high shear rate—multiple capillary viscometer method"
• Differences from ASTM D5481—96: 1. according to the actual situation of our country's standards, relevant referenced standards were added; 2. requirements for instrument cleaning agents were added
• Publication/implementation: published by 2001-11-23, implemented by 2002-01-01
• Issuing unit: State Economic and Trade Commission
• Responsible organization: Sinopec Research Institute of Petroleum Processing
• Drafting unit: Nanhai Advanced Lubricant Company of Sinopec Maoming Branch
• Main drafters: Han Shenjun, Chen Dong, Wang Xuemei, Lin Weihong
• Appendices: Appendix A and Appendix B are both appendices of the standard

2. Scope of application and non-applicability

• 1.1 specifies the method for determining the high-temperature high-shear (HTHS) apparent viscosity of engine oils using a multiple capillary viscometer equipped with pressure measurement, temperature measurement, and timing devices under the conditions of 150℃ and a tube-wall apparent shear rate of 1.4×10⁶ s⁻¹ (the original source-text extraction is "1.4x108s-1", requires confirmation against the source standard (source-text extraction)).
• 1.2 The shear rate specified in this standard can reduce the difference between this method and other test methods for determining high-temperature high-shear apparent viscosity. This standard directly measures viscosity by using a calibration curve established with Newtonian oils having an apparent viscosity of 2 mPa·s~5 mPa·s at 150℃.
• 1.3 This standard may involve certain hazardous materials, operations, and equipment. This standard does not purport to address all safety problems associated with it. It is the responsibility of the user of this standard to establish appropriate safety and protective measures and determine appropriate management systems before use.
• Non-applicability: no explicit non-applicability clause is provided in the available source.

3. Method principle

• 4.1 Under the test conditions of 150℃, under the pressure of nitrogen (or carbon dioxide), the sample is made to flow out of the capillary viscometer. From the outflow time and pressure of the sample, the apparent viscosity of the sample can be obtained when the tube-wall apparent shear rate of the capillary viscometer reaches 1.4×10⁶ s⁻¹ (the original source-text extraction is "1.4×10%s-", requires confirmation against the source standard (source-text extraction)). The oil viscosity corresponding to the measured pressure can be determined by using the calibration curve for each viscometer cell.
• 4.2 The calibration curve of each viscometer cell is established from the relationship between pressure and flow rate for a series of Newtonian oils of known viscosity.
• 3.1 Tube-wall apparent shear rate definition formula (1): S = 4V / (πR³t) (the original source-text extraction is "S.=4. mR' • (1)", requires confirmation against the source standard (source-text extraction)); where S is the tube-wall apparent shear rate (s⁻¹), V is volume (mm³), R is capillary radius (mm), and t is outflow time (s).
• 3.8 Shear stress definition formula (2): Z = PR / 2L; where Z is shear stress (Pa), P is pressure drop (Pa), R is capillary radius (mm), and L is capillary length (mm).

4. Reagents and materials (purity / preparation)

• 7.1 Newtonian oil or fluid: has a definite viscosity value at 150℃, in the range of 2.0 mPa·s~7.0 mPa·s (see Table 1).
• Table 1 Calibration oils:
  • HT39: approximate viscosity 2.0 mPa·s, approximate pressure during test 1500 kPa
  • HT75: approximate viscosity 2.7 mPa·s, approximate pressure during test 2000 kPa
  • HT150: approximate viscosity 3.7 mPa·s, approximate pressure during test 2500 kPa
  • FT240: approximate viscosity 5.0 mPa·s, approximate pressure during test 3300 kPa
  • HT390: approximate viscosity 7.0 mPa·s, approximate pressure during test 4500 kPa
  • Note: *The accurate viscosity value is provided by the supplier.
• 7.2 Non-Newtonian reference sample: has a definite high-temperature high-shear viscosity at 150℃, 10⁶ s⁻¹ (the original source-text extraction is "108s[unreadable sign]'", requires confirmation against the source standard (source-text extraction)).
• 7.3 Carbon dioxide or nitrogen cylinder: equipped with a pressure reducing valve, maximum pressure not less than 3500 kPa (500 psi).
• 7.4 Cleaning agent: toluene or other high aromatic solvent, lubricating base oil with kinematic viscosity at 40℃ less than 13 mm²/s, or transformer oil conforming to GB 2536 standard.
• Appendix A Reference liquid: CANNON standard is HT150 or an equivalent substitute; additionally rinse with isooctane or a suitable substitute solvent (the original source-text extraction is "[garbled isooctane name]", requires confirmation against the source standard (source-text extraction)).

5. Instruments and equipment

• 6.1 High-temperature high-shear (HTHS) viscometer: includes several viscometer cells in a controllable temperature body, as well as devices capable of controlling the test temperature, applied pressure, and measuring the sample outflow time. Each viscometer cell contains a precision glass capillary and a device for adjusting the sample volume.
• 6.1.1 Typical dimensions and specifications of the HTHS viscometer:
  • Capillary diameter: 0.15 mm
  • Capillary length: 15 mm~18 mm
  • Temperature control: 150℃±0.1℃
  • Pressure range: 350 kPa~3500 kPa
  • Pressure control: ±1%
  • Sample volume: 1 mL (the original source-text extraction is "JmL lmL", requires confirmation against the source standard (source-text extraction))
• 6.1.2 Temperature-measuring thermometer: a presettable digital resistance thermometer whose accuracy can be verified by a thermal well and a thermometer with a precision of 0.1℃ or better.
• 6.2 Medical glass syringe: 10 mL.
• For Appendix A: small long-neck flask (for weighing), plastic cap or small rubber stopper, aluminum block heat conductor thermometer insertion hole (see 9.3).

6. Recommended operating conditions

• Test temperature: 150℃±0.1℃ (6.1.1, 10.5)
• Tube-wall apparent shear rate: 1.4×10⁶ s⁻¹ (the original source-text extraction is "1.4x108s-1", requires confirmation against the source standard (source-text extraction))
• Pressure range: 350 kPa~3500 kPa; pressure control ±1%
• Table 2 Approximate test pressure (by engine oil viscosity grade):
  • 20: 1500 kPa
  • 30: 1750 kPa
  • 40: 2100 kPa
  • 50: 2450 kPa
• Constant temperature time: the viscometer is placed at the test temperature and kept at constant temperature for at least 30 min (10.1); the sample is kept at 150℃±0.1℃ for 15 min (10.5)
• Viscosity range of Newtonian fluid for calibration: at 150℃, 2 mPa·s–5 mPa·s (9.1.2); for Appendix B, use 2.5 mPa·s–4.0 mPa·s (B2)

7. Sampling and sample preparation

• 8 Sampling: sample according to GB/T 4756. A representative sample should not contain suspended solid impurities and moisture, which is necessary to obtain valid results. If impurities are present, they must be removed by filtration with 10 μm filter paper (the original source-text extraction is "10ym", requires confirmation against the source standard (source-text extraction)).
• 10.2 Rinse with 4 mL~6 mL sample to remove previous residues.
• 10.3 Inject 9 mL~11 mL sample.

8. Analysis procedure

• 10.1 Place the viscometer at the test temperature and keep at constant temperature for at least 30 min. Install a 10 mL medical glass syringe at the top of each viscometer.
• 10.2 Rinse with 4 mL–6 mL sample to remove previous residues. Open the top stopcock valve, and pressurize to allow the sample to enter the viscometer. Inject 4 mL–6 mL sample, and close the top stopcock valve. Open the pressure valve until the rinse sample has completely flowed out through the capillary, then close the pressure valve.
  • Warning: Except when loading the sample or adjusting the sample volume, the top stopcock valve should remain closed; never open the pressure valve while the top stopcock valve is open.
• 10.3 Open the top stopcock valve, inject 9 mL~11 mL sample, and close the top stopcock valve.
• 10.4 Repeat steps 10.2 and 10.3 for the remaining viscometer cells.
• 10.5 Keep the sample at 150℃±0.1℃ for 15 min.
• 10.6 After the temperature is constant, confirm that the top stopcock valve of each viscometer cell is closed. Determine the efflux time and pressure as follows:
  • 10.6.1 Based on the calibration results for the viscometer cell and the estimated viscosity of the sample, predict the pressure required to reach t₀ (see 9.1.1). Table 2 provides approximate set pressures for engine oils of different viscosity grades. Adjust the pressure to within ±1% of the required pressure value and keep the pressure constant.
  • 10.6.2 Reset the timer to zero.
  • 10.6.3 Open the top stopcock valve so that all excess sample is drawn out under negative pressure, immediately close the stopcock valve, and immediately perform the operation of 10.6.4.
  • 10.6.4 Turn on the viscometer cell measurement switch, and record the pressure reading after running for about 10 s.
  • 10.6.5 When the timer stops (indicating that the measurement is complete), turn off the viscometer cell measurement switch and record the efflux time. During the test, it is sometimes necessary to adjust the timer indicator to ensure that the timing is consistent with the instrument's "start" and "end" signals.
  • 10.6.6 Repeat steps 10.6.1 to 10.6.5 for the remaining viscometer cells.
  • 10.6.7 After the test is completed, the viscometer cell must be cleaned. If toluene or another highly aromatic solvent is used for cleaning, the temperature of the viscometer cell must not exceed 100℃; if a lower-viscosity lubricating base oil or transformer oil is used for cleaning, it must be filtered before use. In addition, to ensure the reliability of the test, after completing a series of tests, the viscometer must be cleaned with toluene or another highly aromatic solvent.
• 9 Calibration and standardization:
  • 9.1.1 The volume and diameter of each capillary viscometer cell are provided by the manufacturer. When the apparent shear rate at the tube wall is 1.4×10⁶ s⁻¹, the efflux time t₀ can be calculated by formula (3): t₀ = 4V / (1.4×10⁶ R³) (the source text source-text extraction is "to= 4V / i.4×10 R", requires confirmation against the source standard (source-text extraction)); when the viscometer cell is changed, its volume must be re-determined; see Appendix A for the determination method.
  • 9.1.2 Use at least four Newtonian calibration oils (150℃, viscosity range covering 2 mPa·s~5 mPa·s) to determine the relationship between pressure and flow rate. For each calibration oil, the pressure needs to be adjusted so that the efflux time is within ±20% of the nominal efflux time. Each cell needs to be measured three times for each calibration oil.
  • 9.1.2.1 The viscosity can be calculated by formula (4): η = C₁t + C₂/t + C₃ (the source text source-text extraction is ": (4)", the main body of the formula is missing, requires confirmation against the source standard (source-text extraction)); where η is viscosity (mPa·s), t is efflux time (s), P is pressure (kPa), and C₁, C₂, C₃ are calibration coefficients for each viscometer cell.
  • 9.1.2.2 The calibration coefficient C₁ is obtained by calibrating the pressure of each viscometer cell. Usually, within a relatively narrow range of shear rate and viscosity relevant only to the determination of high-temperature viscosity of automotive engine oils, the calibration coefficient C₁ is essentially constant. In generalized applications, for all Reynolds constants (Re), C₂ may not be constant.
  • 9.1.2.3 The procedure for determining C₁, C₂, and C₃ is given in Appendix B.
  • 9.2 Stability of the viscosity calibration curve: Test the calibration oil in the same way as the sample to check the stability of the calibration curve. The calibration work for the stability of the viscosity calibration curve must be performed before each new round of tests or once every twenty tests. Non-Newtonian calibration oils must undergo a stability test at least once a month. The viscosity of the calibration oil measured in the stability test should be the same as the standard value of the repeatability test described in clause 13.1.1. If it exceeds the range, and the repeatability determination shows that the result is correct, then the root cause of the problem must be found and corrected, and if necessary, the entire calibration process should be repeated. To find the root cause of the problem, the entire system that produced the erroneous result should be thoroughly inspected to determine the steps that may have caused the error, including checking for foreign matter in the capillary, verifying the accuracy of the operating procedure, and the accuracy of temperature control and readings, etc.
  • 9.3 Stability of temperature verification: Insert a standard thermometer into the thermometer hole of the aluminum block heat conductor to check the calibration stability of the temperature sensor, at least once a year.
• Appendix A Determination of viscometer cell volume:
  • A1 Keep the viscometer cell at 100℃ for cleaning. Inject 10 mL toluene or another highly aromatic solvent into each viscometer cell, then flush it out. Repeat twice, then rinse with isooctane or a suitable alternative solvent.
  • A2 Blow away the solvent in the cell with air, nitrogen, or carbon dioxide.
  • A3 Select a reference liquid (CANNON standard is HT150 or an equivalent substitute). Add the reference liquid to each viscometer cell and keep it at 150℃ or the temperature required for the test for 15 min. Open the stopcock valve and draw out excess sample. Close the stopcock valve and, by gas pressure, cause the reference liquid to flow out of the discharge tube at the bottom of the viscometer cell.
  • A4 Plug the lower bottom end of each metal tube with a plastic cap or small rubber stopper, so that an air lock is created between the oil stored in the upper part of the cell, the glass capillary, and the end of the discharge tube.
  • A5 Take a small long-neck flask and weigh it, place it under each discharge tube so that the mouth of each long-neck flask is slightly higher than the end of the discharge tube.
  • A6 Fill each viscometer cell with the reference liquid and keep it at the test temperature for 15 min. Open the stopcock valve and draw out excess sample. Close the stopcock valve, remove the plastic cap or stopper on the discharge tube, turn on the measurement switch, and allow the reference liquid to flow out of the discharge tube.
  • A7 Turn off the measurement switch.
  • A8 Weigh each long-neck flask, subtract the mass of the empty flask, and determine the volume of the sample: V = W/d (formula A1); where V is volume (mL), W is the measured mass (g), and d is the density of the liquid (g/cm³), provided by the supplier of the reference liquid.
  • A9 Repeat steps A4 to A8 three times.
  • A10 Determine the average volume V, and determine the standard deviation from the three volume values measured for each viscometer cell. If the standard deviation is greater than 0.05 mL, repeat the entire procedure.
• Appendix B Calculation of formula coefficients:
  • B1 The viscosity calculation formula is as follows (the source text source-text extraction is "•(B1)", the main body of the formula is missing, requires confirmation against the source standard (source-text extraction)). It is required to determine the coefficients C₁, C₂, and C₃. The nominal efflux time t₀ corresponding to an apparent shear rate at the tube wall of 1.4×10⁶ s⁻¹ must also be determined.
  • B2 Using viscosity standard samples with apparent viscosity in the range of 2.5 mPa·s~4.0 mPa·s and with known density, determine t₀ according to Chapter 10.
  • B2.1 Adjust the volume of the sample to be tested (10.6.3), place a pre-weighed long-neck small bottle below the outlet of the viscosity tube, turn on the run switch (10.6.4), collect the effluent, and measure the mass of the effluent liquid M.
  • B2.2 According to the methods in steps 10.6.4 and 10.6.5, calculate the volume of the effluent at that efflux time: V = 1000M/ρ (formula B2); where V is the volume of the effluent (mm³), M is the mass of the effluent (g), and ρ is the density (g/cm³).
  • B2.3 Calculate t₀ according to the method in step 9.1.1. If no special provision is made for the capillary, then R = 0.075 mm.
  • B3 C₃ is a relatively small correction factor. When the efflux time exceeds t₀ ±5%, if only a small change occurs in the fluid volume, then C₃ can be determined using a Newtonian fluid of known viscosity; usually, C₃ = 0.075 is sufficient.
  • B4 When the efflux time is within t₀±1 s, measure the efflux time under different pressures using at least four Newtonian fluids of different viscosities, and process the measured data by regression according to the following formula (the source text source-text extraction is "[1+G1- )]", the main body of the formula is missing, requires confirmation against the source standard (source-text extraction)).
  • B4.1 Using the values of C₁, C₂, and C₃ and the measured P and t, calculate the viscosity. After determining the viscosity, calculate the deviation as a percentage of the corrected viscosity. If the deviation is greater than 1.5%, it indicates that the data are unreliable.
  • B4.2 The calculator equipped with the high-temperature high-shear viscometer can perform the regression and comparison described in B4 and B4.1.

9. Qualitative and quantitative determination and calculation formulas

• 11.1 From the efflux time and gas pressure obtained from the sample measurement, the calculation is automatically performed by computer using relevant software and calibration coefficients. Calculate the viscosity of the sample in each viscometer cell and the apparent shear rate at the tube wall. If the apparent shear rate at the tube wall is not within ±5% of 1.4×10⁶ s⁻¹ (the source text source-text extraction is "1.4x109-1", requires confirmation against the source standard (source-text extraction)), the computer will indicate the approximate pressure for the next test. Readjust the required pressure and perform a second measurement in the same or a different cell.
• 11.2 If it is only necessary to determine that the sample viscosity exceeds a certain specified viscosity, then it is not necessary to measure the actual viscosity of the sample. The pressure of each viscometer cell can be calculated and calibrated from the specified viscosity and the efflux time t₀. If the measured efflux time exceeds t₀, then the sample viscosity must also exceed the specified viscosity.
• Relevant formulas:
  • Formula (1) tube wall apparent shear rate: S = 4V / (πR³t)
  • Formula (2) shear stress: Z = PR / 2L
  • Formula (3) nominal efflux time: t₀ = 4V / (1.4×10⁶ R³)
  • Formula (4) viscosity: η = C₁t + C₂/t + C₃ (the main body of the formula source-text extraction is missing, requires confirmation against the source standard (source-text extraction))
  • Formula (5) repeatability = arithmetic mean × 1.6%
  • Formula (6) reproducibility = arithmetic mean × 5.4%
  • Formula (A1) volume: V = W/d
  • Formula (B2) effluent volume: V = 1000M/ρ
  • Formula (B1) viscosity calculation formula: the original text source-text extraction is missing, requires confirmation against the source standard (source-text extraction)

10. Precision

• 13.1 Precision: judge the reliability of test results according to the following provisions (95% confidence level).
  • 13.1.1 Repeatability (r): the difference between two consecutive results obtained by the same operator using the same equipment under the same operating conditions on the same test sample shall not exceed the value obtained by formula (5): repeatability = arithmetic mean × 1.6%.
  • 13.1.2 Reproducibility (R): the difference between two results obtained by different operators in different laboratories using the same test method shall not exceed the value obtained by formula (6): reproducibility = arithmetic mean × 5.4%.
• 13.2 Bias: This standard uses a calibration curve established with standard values of known viscosity, and then determines the viscosity of the test sample by interpolation. This standard value is specified as an accurate value. Therefore, as a comparative method for measuring viscosity, this test method has no bias.

11. Report

• 12 Report the high-temperature high-shear apparent viscosity of the test sample in units of mPa·s (millipascal·second), retaining two decimal places, and also report the test temperature (℃).

12. Normative references

• GB 2536 Transformer oil
• GB/T 4756 Manual sampling method for petroleum liquids (the original text source-text extraction is "CB/T 4756", requires confirmation against the source standard (source-text extraction))
• ASTM D5481—96 (the original standard equivalently adopted)

13. Source and verification

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14. Quick Q&A