Research Papers: Flows in Complex Systems

New Discharge Coefficient of Throat Tap Nozzle Based on ASME Performance Test Code 6 for Reynolds Number From 2.4 × 105 to 1.4 × 107

[+] Author and Article Information
Yoshiya Terao

National Institute of Advanced
Industrial Science and Technology,
National Metrology Institute of Japan,
Tsukuba-Central 3, 1-1-1 Umezono,
Tsukuba, 305-3563, Japan

Shinichi Nakao

Flow Measurement Consulting
Laboratory Flow Col,
Youkoudai 4-27-7, Isogo-ku,
Yokohama, 235-0045, Japan

Kazuo Shibuya

Flow Engineering Co., Ltd.,
Tsuruyacho 2-13-2, Kanagawa-ku,
Yokohama, 221-0835, Japan

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received June 3, 2013; final manuscript received September 18, 2013; published online October 18, 2013. Assoc. Editor: Frank C. Visser.

J. Fluids Eng 136(1), 011105 (Oct 18, 2013) (10 pages) Paper No: FE-13-1353; doi: 10.1115/1.4025513 History: Received June 03, 2013; Revised September 18, 2013

The throat tap nozzle of the American Society of Mechanical Engineers performance test code (ASME PTC) 6 is widely used in engineering fields, and its discharge coefficient is normally estimated by an extrapolation in Reynolds number range higher than the order of 107. The purpose of this paper is to propose a new relation between the discharge coefficient of the throat tap nozzle and Reynolds number by a detailed analysis of the experimental data and the theoretical models, which can be applied to Reynolds numbers up to 1.5 × 107. The discharge coefficients are measured for several tap diameters in Reynolds numbers ranging from 2.4 × 105 to 1.4 × 107 using the high Reynolds number calibration rig of the National Metrology Institute of Japan (NMIJ). Experimental results show that the discharge coefficients depend on the tap diameter and the deviation between the experimental results and the reference curve of PTC 6 is 0.75% at maximum. New equations to estimate the discharge coefficient are developed based on the experimental results and the theoretical equations including the tap effects. The developed equations estimate the discharge coefficient of the present experimental data within 0.21%, and they are expected to estimate more accurately the discharge coefficient of the throat tap nozzle of PTC 6 than the reference curve of PTC 6.

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Fig. 1

Schematic diagram of throat tap nozzle

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Fig. 2

Flow sheet of high Reynolds number calibration rig

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Fig. 4

Detail of pipe layout

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Fig. 5

Schematic diagram of measurement (a) using the weighing tank and (b) using reference flowmeters

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Fig. 6

The discharge coefficient for different measurement condition

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Fig. 7

The discharge coefficient for different nozzle

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Fig. 8

The discharge coefficient for different azimuthal position

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Fig. 9

The discharge coefficient for variable tap diameter (a) and normalized difference of discharge coefficients (b)

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Fig. 10

Measurement uncertainty of discharge coefficient

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Fig. 11

Discharge coefficient by theoretical analysis

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Fig. 12

Relationship between ΔC/(dTap/d) and Reynolds number

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Fig. 13

Comparison between PTC 6 and developed new equation



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