1. AWG 2011 – CVI Update
K Turnbull, P Barrett

2. Table of Contents
Organics
Infrastructrure Upgrades CVI Replacement
Lyman Alpha Hygrometer Baseline
Size dependant collection effeciency (large particles >25micron)
COSIC

3. Organics
Tip cleaned
Furnace heated in 02 deficient atmosphere to prevent combustion
2-cycles at up to 700°C
Desorbtion of materials
Followed by ultrasonic bath to remove and residual particles
Testing problems at Icing Tunnel and on Aircraft – Autumn 2010 – AMS fuses
Ongoing – awaiting tests, Aircraft or Icing tunnel

4. CVI Replacement
Limited options – depends on driver from results of organics tests
Rought draft of document circulated, but effort put on hold, awaiting funding news
Using the Brechtel Iso-kinetic inlet (MOCCA aircraft) may stimulate interest in aquiring a Brechtel CVI for BAe146?
No money? None at Met Office!
If organics are present – see following table:

5. New control software needed to collect data from external instruments
Money
Time
1. Brechtel
Pros:
Purpose built, other groups use same
Minimal design work for CVI
CFD is underway on inlet
$$$$$
80K
+ Recert. costs
&&&
Redesign full rack,
New control software needed to collect data from external instruments
Cons:
price
Time – redesign of rack
recert. Costs,
new hole in aircraft skin
2. Modify Current CVI tip
We can redesign tip for new science reqs.
Lower cut size
Sample larger particles
Better heating / deicing
Keep same inlet arm
Cheaper $$
Exeter Uni Engineering support – fairly cheap, but may need prototypes for mods
&&&&
Redesign tip, including testing, verification of transmission efficiency
Needs to build and test prototypes?
same pumping/drying system,
same (lossy) plenum distribution
need to design, draw and build (outsource) manufacture of new tip
no CFD to check tip design
Need to prove inlet works in order to publish
Waste of money if tip fails
3. Make direct copy of current tip
Cheap
easiest option
remove (possible) organics contam. $
Exeter Uni Engineering support – fairly cheap
Cost~4k – for alu tip w/ heaters, etc
&
Design time
(Solidworks) needed
Cut size is too high
tip is blunt
very hard to heat/de-ice the tip
inlet is narrow – low efficiency for large (ice) particles

6. Lyman Alpha Hygrometer
Lab work to determine baseline drift due to
electronics – detector+amps
humidity exposure
density
Data Analysis to fit “out of cloud” baseline drift due to
Sample Air Density (due to O2 absoprtion of ly-A)
cumulative moisture exposure (“Fogging” of Mg2F windows due to H2O and λ(uv))
Ongoing – but progress made

7. Size Dependant Collection Efficiency – Large Particles
Comparison vs. Nevzorov, low IWC during CONSTRAIN – B496
m=~0.5
m=~0.8
Nevz. vs. CVI. For
Left: MVD < 75µm
Right: MVD > 150µm
Nevz. vs CVI. IWC with MVD filtering

8. COSIC work Ongoing – data to be reprocessed – watch this space
Work on CONSTRAIN hygrometer will inform on re-procseeing requirements
May be possible to recover the data for B516, B517

9. The Future CVI will fly during COALESCE – AMS testing?
PCASP has been upgraded to SPP-200 electronics, with the same laser, and optics block as previous. Flight testing during COALESCE
Any funding for upgrades?
Next projects for CVI/AMS?

10. Extra slides

11. Attack Angle Efficiency
B496 CVI vs Nevz as Fn(AoA)
B496 CVI vs Nevz as Fn(Pitch)

12. Altitude Dependance Not much
Nevz. Goes –ve in places due to imperfect baseline
CVI does the same but has set to zero here, where -ve

13. Lyman-A baseline fit