Tri-lateral comparison CMI-PTB-VNIIR to evaluate bell provers Status report E1396 Tri-lateral comparison CMI-PTB-VNIIR to evaluate bell provers Bodo Mickan Thomas Valenta Oleg Kalinin Aleksey Biziaev

Bell provers of PTB-type recently built up (since 2011) 1…100 m3/h Sinking mode (extending to rising?) Shell Morlina 5 CMI (2015) 1…250 m3/h Sinking and rising mode VNIIR (2016) Sinking mode Other Oil Inter comparison using sonic nozzles Investigation on oil film thickness to ensure and enhance uncertainty budget regarding this point

Inter comparison using sonic nozzles sonic nozzles with nominal flow rates:   250 m3/h 150 m3/h 75 m3/h 12 m3/h 2,5 m3/h 1 m3/h. CMI Bell Prover PTB secondary VNIIR secondary PTB Bell Prover VNIIR Bell Prover Nozzles ready to go here

Investigation on oil film thickness to ensure and enhance uncertainty budget regarding this point Counter weight Bell (wall)

Investigation on oil film thickness to ensure and enhance uncertainty budget regarding this point Counter weight Bell (wall) „plus“ for descending; „minus“ rising mode; DV always shrinking Vmeas

In-Situ measurement of oil film 17.5 pixel/mm 0.3 pixel resolution using cross correlation of images

In-Situ measurement of oil film Change of Dp between bell (inside) and atmosphere also change indication simultaneous measurement of Dp and correction for it. you need at least 1 Pa Dp resolution

Normalization of values using theories Draining flow Dragged film by moving wall Simple approach [Smith 1938] (draining in balance with dragging at touching point without consideration of meniskus) Enhanced (considering meniscus) [Landau 1942] d0 Landau‘s solution recently perfectly confirmed in new measurements (2011)

d0 either from theory or adopted to get Vn = 1 at t = 0

  Measurand Unit Correlation Dp Dp Bell – Atmosphere mbar non Ioillevel Pixel indication Pixel Dpref Dp Bell – Atmosphere for Ref.-image Within one series fpix Conversion factor Pixel/mm mm/Pixel AW Wall surface mm2 Vevap Evaporation rate of the oil mm3 Agap,total Total open oil surface Among all Agap,in Open oil surface inside bell r Density of oil kg/m3 g Earth acceleration m/s2 d0 is a parameter to be adopted for best fitting of all results into one curve

Compare experimental values of d0 with simple and enhanced theory

Summary We have an universial function for film thickness at any time for any type of oil. Confirmed by In-Situ measurements Reasonable consistent with theories Applicable for rising and sinking mode of bell provers

Note on oil evaporation Bowl with 540 cm2 surface at a balance Time [h] Dm [mg] Shell Morlina 5: 4,5 g/h/m2 What does it mean for our sonic nozzles?

Physikalisch-Technische Bundesanstalt Braunschweig und Berlin Bundesallee 100 38116 Braunschweig Bodo Mickan Arbeitsgruppe 1.43 Hochdruck-Gas Telefon: 0531 592-1331 E-Mail: bodo.mickan@ptb.de www.ptb.de Stand: 03/14