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Dr. B. Mickan, 20 th Sep Reqirements of Nozzle Shape ISO9300 versus reality Dr.-Ing. B. Mickan; PTB Sonic Nozzle Workshop; ; Poitiers

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Dr. B. Mickan, 20 th Sep 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 Content

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Dr. B. Mickan, 20 th Sep Requirements out of ISO divergent section: steps, discontinuities, deviation from circularity shall be < 1% d local but Ra shall be < d (7.1.4) - Inlet section: Ra shall be < 1.5 d (7.1.3 [ ]) - Inlet section: curvature of toroid shall be 1.8 < R c < 2.2 deviation from ideal toroid form always < d ( )

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Dr. B. Mickan, 20 th Sep Indirect measures of geometry for small nozzles R C = G -1 (b) [Geropp]; a = H(R C ) (Kliegel/Levine, Hall, Oswatitsch) R C … 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

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Dr. B. Mickan, 20 th Sep Indirect measures of geometry for small nozzles It is not very likely that the curvature can be fullfilled for small nozzles near to the throat.

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Dr. B. Mickan, 20 th Sep Indirect measures of geometry for small nozzles d -0.4 Red – manufacturer info Blue – PTB measurement

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Dr. B. Mickan, 20 th Sep Indirect measures of geometry for small nozzles Red – manufacturer info Blue – PTB measurement In average we have agreement between dimensional measurement and flow measurement !!

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Dr. B. Mickan, 20 th Sep Measurement procedure of inner shape (PTB) X Y Z 0 hh Y zAzA zEzE zHzH -8 lines points each line - one circle with 360 points at throat

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Dr. B. Mickan, 20 th Sep Measurement procedure of inner shape (PTB) Approximation with B-Splines

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Dr. B. Mickan, 20 th Sep Measurement procedure of inner shape (PTB) For c D = => displacement thickness is d => What is a relevant roughness?

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Dr. B. Mickan, 20 th Sep Nozzle shapes from real live Nozzle d throat = 26,0395 mm

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Dr. B. Mickan, 20 th Sep Nozzle shapes from real live Nozzle d throat = 6,5147 mm

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Dr. B. Mickan, 20 th Sep Nozzle shapes from real live Nozzle d throat = 3,2566 mm

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Dr. B. Mickan, 20 th Sep Other Nozzle shapes and cD-Value Nozzled Throat [mm] #10,9915 #21,3436 #32,295 #43,903 #56,646 #611,261

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Dr. B. Mickan, 20 th Sep 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

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Dr. B. Mickan, 20 th Sep Conclusions/discussion/proposals Is it helpful to define the measurement procedure of dimensional measurement as well as evaluation of it? Determination of an average R C (physically weighted [Geropp])? c D as a function of such a R C (0.8 [?] < R C < 5[?]) (e.g. addionally supported by theoretical/numerical knowledge)?

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