Final Report COOMET.M.V-S2 (587/RU-a/12) COOMET SUPPLEMENTARY COMPARISON IN THE FIELD OF MEASUREMENTS OF LIQUIDS KINEMATIC VISCOSITY List of authors: a) Coordinator of comparison: Alexey Demyanov, D. I. Mendeleyev Institute for Metrology (VNIIM) 190005, Russia, St.Petersburg Moskovsky pr., 19 e-mail: A.A.Demyanov@vniim.ru phone: +7 812 323-9605 fax: +7 812 323-9671 b) Researcher: Anastasiya Tsurko, D. I. Mendeleyev Institute for Metrology (VNIIM) 190005, Russia, St.Petersburg Moskovsky pr., 19 e-mail: A.A.Tsurko@vniim.ru phone: +7 812 323-9671 fax: +7 812 323-9671
2 Abstract This report describes the COOMET Supplementary comparison of liquid kinematic viscosity standards of two National Metrology Institutes (NMIs) carried out in the period from February and May, 2013. Three Newtonian liquids with nominal kinematic viscosities of 20 mm²/s, 100 mm²/s, 1000 mm²/s at 20 C were used to determine the degrees of equivalence between the NMIs.The mean values obtained by VNIIM- participant in the CCM.V-K1 comparison, were used as reference values for this COOMET comparison. The relative standard uncertainty of the reference valuesranges from 0,096 % at 20 mm²/s to 0,4 % at 1000 mm²/s and 20 C.
3 CONTENTS CONTENTS... 3 1. Introduction... 4 2. Participants... 4 3. Organization of comparisons... 4 4. Description of the measurement method... 6
4 1. Introduction This comparison was conducted by decision of the 16th Meeting of COOMET TC 1.6 "Mass and related quantities", held in St. Petersburg from 27 to 30 September 2011. The pilot laboratory was VNIIM. Each NMI presented the results of measurements with corresponding uncertainties and uncertainty budget. The aim of the present comparison was to confirm the calibration and measurement capabilities (CMC) of the participating NMIs. 2. Participants Information about the participants is shown in Table 1. Table 1. Participants in COOMET.M.V-S2 NMI Address NMI abbreviation 1 D. I. Mendeleyev 190005, Russia, VNIIM Institute for St.Petersburg Metrology Moskovsky pr., 19 2 The Republican State Enterprise with the right of economic conducting The Kazakhstan Institute of Metrology 3. Organization of comparisons 010000, Republic of Kazakhstan, Astana, left Bank, Orynbor str., 11 KazInMetr Contact person Alexey Demyanov E-mail, phone, fax e-mail:a.a.demyanov@vniim.ru phone: +7 812 323-9605 fax: +7 812 323-9671 Ulan e-mail: ulan_mol@mail.ru Moldagana phone: +7 7172 270-958 -pov The comparison schedule and additional information are given in tables 2 and 3, respectively. Table 2. Comparison schedule Date Event September, 2011 Decision to carry out the comparison taken at the 16th Meeting of COOMET TK 1.6 May, 2012 Preparation of the first draft of Technical Protocol September, 2012 Approval of the Protocol at the 17th Meeting of COOMET TK 1.6 October, 2012 Acquisition of liquids, vials and preparation of specimens November, 2012 Measurements of liquids by the pilot laboratory, testing their stability and uniformity, shipping to the participating laboratories January, 2013 Measurements in by participating laboratories March, 2013 Sending liquids to the pilot laboratory, implementation of control measures in the pilot laboratory September, 2013 Testing the stability of liquids at 20 ºС. Receiving reports from the participants October, 2013 Draft A report December, 2013 Draft B report
Table 3. Additional information on the COOMET.M.V-S2 comparison Information Note 1 Circulation of the transfer standards Radial 5 2 Purpose of the comparison Confirmation of measurement and calibration capabilities (CMC) claimed by the participating NMIs 3 Dates of measurements VNIIM "20" 23.04.2013 "100" 17.04.2013 "1000" 25.04.2013 KazInMetr "20" 26.04.2013 "100" 27.04.2013 "1000" 04.05.2013 4 Measurement conditions VNIIM "20" t=21,1 ºС, p=101,2 kpa, φ=45,3 % "100" t=21,3 ºС, p=101,6 kpa, φ=44,8 % "1000" t=20,8 ºС, p=100,4 kpa, φ=44,3 % KazInMetr "20" t=22,4 ºС, p=97kpa, φ=43 % "100" t=24,2 ºС, p=96,6 kpa, φ=33 % "1000" t=21,3 ºС, p=97,9 kpa, φ=32,4 % 5 Transfer standards: «20», «100» и «1000» Name of the standard Liquid Type REV Model of the standard «20», «100», «1000» Packaging description Bottles of dark color with a capacity of 500 ml. 6 Packing and unpacking Packing content Three dark bottle of 500 ml each containing liquid «20», «100» and «1000» Sequence of actions in the NMI when unpacking Upon receipt, the vials are kept unopened in the standard of comparison the participating laboratory for at least two days. Bottles and seals shall be opened only for measurements. Before opening the bottles, you must still check them every time for visible damages or dirt. All significant problems should be specified in the report. Note: Physical constants of liquids are shown in tables 4 and 5.
Table 4. Temperature coefficient of volume expansion Liquid β, kg/(m 3 K) Uncertainty, kg/(m 3 K), k=1 1 «20» 0,60 0,05 2 «100» 0,60 0,05 3 «1000» 0,60 0,05 Table 5. The nominal value of the surface tension and density values Liquid, mn/m Density, kg/m 3 1 «20» 31 860 2 «100» 31 880 3 «1000» 31 890 4. Description of the measurement method 6 All participants, when measuring the viscosity of each liquid sample, use two Ubbelohde viscometer (which are national standards in the participating countries) with close values of the calibration constant. The viscosity of each liquid sample was measured 10 times by each viscometer at the temperature of 20 C. The kinematic viscosity was calculated by the formula 1: γ - kinematic viscosity mm 2 /s;b - correction for the loss of fluid kinetic energy, mm 2 ;K - calibration constant of the viscometer, mm 2 /s 2 ;t - time of liquid flow through the capillary viscometer, s;g, g cal - the acceleration of gravity at the place of measurement of viscosity and calibration of viscometer, m 2 /s. The relative expanded uncertainty of measurement of the fluid viscosity (Uoγ) was calculated by each participant. Formula 2 was used to calculate the uncertainty in measurement of the kinematic viscosity of the samples:. (1) (2) u ok -relative standard measurement uncertainty constant K of the primary standard; u ob - relative standard uncertainty of measurement of the constant B of the primary standard; u ϑγ - relative standard uncertainty caused by the temperature gradient; u осх - relative standard uncertainty of fluid flow through the capillary viscometer; u oτ - relative standard uncertainty of the time counter.
7 5. Comparison results The measurement results and the value of the relative expanded uncertainty of measurement of kinematic viscosity of the liquid obtained by the participants received the comparisons are shown in Table 6. Table 6. Measurement results and values of the expanded uncertainty in measurement of the kinematic viscosity of liquids. COOMET.M.V-S2 (587/RU-a/12) SUPPLEMENTARY COMPARISONS OF COOMET IN THE FIELD OF MEASUREMENTS OF LIQUIDS KINEMATIC VISCOSITY Participant Liquid "20" Liquid "100" Liquid "1000" γ, (mm 2 /s) u γ,% Δ γ, (mm 2 /s) y, (mm 2 /s) u γ,% Δ γ, (mm 2 /s) y, (mm 2 /s) u γ,% Δ γ, (mm 2 /s) VNIIM 19,446 0,096 112,49 0,10 1007,3 0,1 KazInMetr 19,453 0,255 + 0,007 112,68 0,32 + 0,19 1006,8 0,4-0,5 Note: The values of VNIIM are taken as the reference values; u γ,%- expanded relative uncertainty of measurement of viscosity of liquid by each participant (k=2); Δ γ - absolute deviation of the result KazInMetr from VNIIM result. Figs. 1 to 3 show the results of the supplementary comparison.
8 Fig. 1. Liquid "20" (mm 2 /s) Fig. 2. Liquid "100" (mm 2 /s) Fig. 3. Liquid "1000" (mm 2 /s)
9 6. Uncertainty budgets and confirmation of calibration and measurement capabilities (CMCs) of the participating NMIs Uncertainty budget is shown in Table 7. Table 7. Uncertainty budget Uncertainty VNIIM KazInMetr Liquid Liquid "20" "100" "1000" "20" "100" "1000" 1 Relative standard uncertainty of fluid flow through the capillary 5,53 10-4 5,12 10-4 3,51 10-4 0,19 10-4 2,91 10-4 0,96 10-3 viscometers(u осх ) 2 Relative standard measurement uncertainty constant k of the 3,91 10-4 4,48 10-4 5,45 10-4 1,25 10-3 1,6 10-3 1,65 10-3 primary standard (u ok ) 3 Relative standard uncertainty in measurement of the constant b 1,625 10-4 in the primary standard (u ob ) 4 Relative standard uncertainty caused by the temperature 2,198 10-4 2,21 10-4 2,80 10-4 0,25 10-3 gradient(u ϑγ ) 5 Relative standard uncertainty of the time counter (u oτ ) 2,968 10-5 5,13 10-5 0,57 10-6 0,50 10-5 0,46 10-5 0,49 10-5 6 The combined standard uncertainty in measurement of kinematic viscosity of liquids 0,479 10-3 0,501 10-3 0,613 10-3 1,275 10-3 1,632 10-3 1,802 10-3 (u c ) 7 Relative expanded uncertainty in measurement of kinematic viscosity of liquids (U op ), k=2 0,0958 0,100 0,12 0,2548 0,326 0,36 The participants CMCs was assessed according to the COOMET "Guideline on COOMET supplementary comparison evaluation" (R/GM/19:2008). Сomparison COOMET.MV-S2 (587/RU-a/12) was classified as type II, in accordance with COOMET R/GM/19:2008. The procedure for evaluation of data on this comparison type is as follows:: 1. Reference value of the supplementary comparison: The reference laboratory (VNIIM) on the basis of measurement results or calculations establishes the supplementary comparisons reference value the traveling standard value assessment and corresponding uncertainty: x ref, u(x ref ). 2. Checks the consistency of the comparison data (criterion E n ) according to formula 3: (3) If the criterion E n value calculated in accordance with the result provided by i-th NMI doesn t exceed 1 with the coverage level 0,95, then it could be acknowledged that this NMI data confirm announced uncertainties. Note:The covariance value for these comparisons is set to zero, cov(x i,x ref )=0. The estimated results of this supplementary comparison are shown in Table 8.
Table 8. Evaluated data obtained in the supplementary comparison Liquid (x KazInMetr -x ref ), mm 2 /s u 2 (x KazInMetr )+u 2 (x ref ) E n "20" 0,007 0,0717 0,013 "100" 0,19 0,1124 0,283 "1000" 0,5 0,17 0,61 10 7. Conclusion The data of participants are in agreement with respect rthe the the criterion En, which confirms the stated uncertainty claimed by the KazInMetr. 8. Acknowledge We are grateful to the KazInMetr for the active participation in these comparisons.
8. References 1. JGCM100:2008 - Guide to the expression of uncertainty in measurement (GUM). 2. JGCM200:2008 International vocabulary of metrology (VIM). 11 3. COOMET R/GM/11:2010 "CООМЕТ Recommendations. Regulations on comparisons national standards NMI COOMET". 4. COOMETR/GM/19:2008 "Guideline on evaluation of the results obtained in COOMET supplementary comparisons".