1. 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

2. 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

3. Inter comparison using sonic nozzles
sonic nozzles with nominal flow rates:
  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

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

5. 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

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

7. 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

9. 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)

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

11. 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

13. Compare experimental values of d0 with simple and enhanced theory

14. 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

15. 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?

16. Physikalisch-Technische Bundesanstalt
Braunschweig und Berlin
Bundesallee 100
38116 Braunschweig
Bodo Mickan
Arbeitsgruppe 1.43 Hochdruck-Gas
Telefon:
Stand: 03/14