1 / 16

Reqirements of Nozzle Shape ISO9300 versus reality

Reqirements of Nozzle Shape ISO9300 versus reality. Dr.-Ing. B. Mickan; PTB Sonic Nozzle Workshop; 2013-09-20; Poitiers. Content. requirements in ISO 9300 for toroidial nozzles (conventional) indirect measures for nozzle geometry for small nozzles

peony
Download Presentation

Reqirements of Nozzle Shape ISO9300 versus reality

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Reqirements of Nozzle ShapeISO9300 versus reality Dr.-Ing. B. Mickan; PTBSonic Nozzle Workshop; 2013-09-20; Poitiers

  2. Content • requirements in ISO 9300 for toroidial nozzles (conventional) • indirect measures for nozzle geometry for small nozzles • procedure of dimensional measurements at PTB (d > 2 mm) • Examples for larger nozzles • relation to cd-values • Conclusions/discussions/proposals

  3. Requirements out of ISO9300 • divergent section: steps, discontinuities, deviation from circularity shall be < 1% dlocal but Ra shall be < 10-4d (7.1.4) • Inlet section: Ra shall be < 1.510-5d (7.1.3 [7.2.2.4]) • Inlet section: curvature of toroid shall be 1.8 < Rc < 2.2 deviation from ideal toroid form always < 10-4d (7.2.2.4)

  4. Indirect measures of geometry for small nozzles RC = G-1(b) [Geropp]; a = H(RC) (Kliegel/Levine, Hall, Oswatitsch)RC … close to curvature at throat but not identical => You can determine b as well as d out of Flow rate measurements at different pressures. Prior information about d:422 nozzles design value or manufacturer spec. 80 nozzles values for d determined at PTB

  5. Indirect measures of geometry for small nozzles Itis not verylikelythatthecurvaturecanbe fullfilledforsmallnozzlesneartothethroat.

  6. Indirect measures of geometry for small nozzles  d -0.4 Red – manufacturer info Blue – PTB measurement

  7. Indirect measures of geometry for small nozzles In averagewehaveagreementbetween dimensional measurementandflowmeasurement !! Red – manufacturer info Blue – PTB measurement

  8. Y X Y Dh 0 Z zE zA zH Measurement procedure of inner shape (PTB) • 8 lines • 200 points each line • one circle with 360 points at throat

  9. Measurement procedure of inner shape (PTB) Approximation with B-Splines

  10. Measurement procedure of inner shape (PTB) ForcD = 0.995 => displacementthicknessis 0.00125d => Whatis a relevant roughness?

  11. Nozzle shapes from real live Nozzle 71996-2013-08 dthroat = 26,0395 mm

  12. Nozzle shapes from real live Nozzle 71988-2013-08 dthroat = 6,5147 mm

  13. Nozzle shapes from real live Nozzle 71986-2013-08 dthroat = 3,2566 mm

  14. Other Nozzle shapes and cD-Value

  15. Conclusions/discussion/proposals • Shape requirements are not very practical • Roughness criteria to sharp for laminar region? • Deviation from toroid form is not so important far away from throat • Curvature at throat is critical in production as well as for cd-behavior • But not as ciritcal as is seems first • Curvature evaluation depends much on measurement and evaluation procedure

  16. Conclusions/discussion/proposals • Is it helpful to define the measurement procedure of dimensional measurement as well as evaluation of it? • Determination of an average RC (physically weighted [Geropp])? • cD as a function of such a RC (0.8 [?] < RC < 5[?]) (e.g. addionally supported by theoretical/numerical knowledge)?

More Related