Extrapolation and Curve-Fitting of Calibration Data for Differential Pressure Flow Meters

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
David R. Keyser ◽  
Jeffrey R. Friedman
Keyword(s):  
Flow Measurement ◽  
Performance Test ◽  
Fluid Dynamic ◽  
Reynolds Numbers ◽  
Differential Pressure ◽  
Calibration Data ◽  
Performance Tests ◽  
Expansion Factor ◽  
Flow Meters ◽  
The One

Performance test codes require primary mass-flow accuracies that in many applications require laboratory quality calibration of differential pressure meters. It is also true that many performance tests are conducted at Reynolds numbers and flows well above the laboratories' capacities, and sound extrapolation methods had to be developed. Statistical curve fits and regression analyses by themselves, absent fluid-dynamic foundations, are not valid procedures for extrapolation. The ASME PTC 19.5-2004 discharge coefficient equations reproduced in this paper for nozzles, orifices, and venturis are suitable for use whenever calibration data are to be applied in a flow measurement and/or extrapolated to higher Reynolds numbers as necessary. The equations may also be used for uncalibrated differential pressure meters by using nominal values. It is necessary to note that the metering runs must be manufactured with dimensions, tolerances, smoothness, etc., and installed in strict accordance with ASME PTC 19.5 for these equations to be valid. Note that for compressible flow, the value of the expansion factor term in the PTC 19.5 equation must be the one corresponding to the published PTC 19.5 equation.

ASME PTC 19.5 Procedures for Application of Laboratory Calibrations of Differential Pressure Flow Meters

2008 ◽  
Author(s):  
Jeffrey R. Friedman ◽  
David Keyser
Keyword(s):  
Discharge Coefficient ◽  
Performance Test ◽  
Fluid Dynamic ◽  
Reynolds Numbers ◽  
Differential Pressure ◽  
Calibration Data ◽  
Performance Tests ◽  
Regression Analyses ◽  
Flow Meters ◽  
Laboratory Calibration

Performance Test Codes require primary mass flow accuracies that in many applications require the laboratory-quality calibration of differential pressure meters. It is also true that many performance tests are conducted at Reynolds numbers and flows well above the laboratories’ capacities, and sound extrapolation methods had to be developed. Statistical curve-fits and regression analyses by themselves, absent fluid-dynamic foundations, are not valid procedures for extrapolation. The ASME PTC 19.5-2004 discharge coefficient equations presented in this paper are suitable for use and extrapolation of laboratory calibration data.

Influence of Glucose Ingestion Prior to Prolonged Exercise on Selected Responses of Wheelchair Athletes

2003 ◽  
Vol 20 (1) ◽  
pp. 80-90 ◽  
Author(s):  
Owen Spendiff ◽  
Ian G. Campbell
Keyword(s):  
Performance Test ◽  
Prolonged Exercise ◽  
Respiratory Exchange Ratio ◽  
Endurance Performance ◽  
Performance Tests ◽  
Wheelchair Athletes ◽  
Cord Injury ◽  
Glucose Ingestion ◽  
The One ◽  
Blood Glucose Concentrations

Eight men with spinal cord injury ingested glucose (CHO) or placebo (PLA) 20-min prior to exercise. Participants performed arm crank ergometry for one-hour at 65% V̇O2peak, followed by a 20-min performance test in which athletes were asked to achieve their greatest possible distance. Physiological responses during the one-hour tests were similar between CHO and PLA trials. At the onset of exercise, the CHO trial blood glucose concentrations were higher than PLA (p < .05) but returned to resting values after 20-min exercise. Respiratory exchange ratio responses during the CHO trial were indicative of a higher rate of CHO oxidation (p < .05). A greater distance (km) was covered in the 20-min performance tests after CHO ingestion (p < .05). Results show preingestion of glucose improves endurance performance of wheelchair athletes.

Comparison of Primary Flow Measurement Techniques Used During Combined Cycle Tests

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
W. Cary Campbell ◽  
Warren H. Hopson ◽  
Mark A. Smith
Keyword(s):  
Flow Measurement ◽  
Performance Test ◽  
Measurement Techniques ◽  
Combined Cycle ◽  
Steam Flow ◽  
Alternative Methods ◽  
Test Results ◽  
Steam Turbines ◽  
Primary Flow ◽  
Flow Meters

One of the most significant contributors to the overall uncertainty of a performance test of a combined cycle steam turbine is the uncertainty of the primary flow measurement. ASME performance test codes provide many alternative methods for determining flow. In two actual combined cycle tests performed in 2005, the following three alternate methods were used to determine the high-pressure (HP) steam flow into the combined cycle steam turbines: (1) Derivation from measured HP feedwater flow using calibrated PTC 6 throat tap nozzles, (2) derivation from low-pressure (LP) condensate using calibrated PTC 6 throat tap nozzles, and (3) derivation from LP condensate using calibrated orifice metering sections. This paper describes the design, calibration, and installation of each flow meter involved, the methods used to calculate the HP steam flow, the estimated uncertainty of the HP steam flow derived using each method, and the actual test results using each method. A comparison of the methods showed that there are distinct advantages with one of the methods and that very low uncertainties in HP steam flow can be achieved if sufficient attention is applied to the design, calibration, and installation of all flow meters involved. Note that the information in this paper was originally published in ASME Paper PWR2006-88074 and presented at the 2006 ASME Power Conference in Atlanta, GA. For detailed diagrams, figures, and tabulations of data and analysis, please refer to the published proceedings from that conference.

Comparison of Primary Flow Measurement Techniques Used During Combined Cycle Tests

2006 ◽  
Author(s):  
W. Cary Campbell ◽  
Warren H. Hopson ◽  
Mark A. Smith
Keyword(s):  
Flow Measurement ◽  
Performance Test ◽  
Measurement Techniques ◽  
Combined Cycle ◽  
Steam Flow ◽  
Alternative Methods ◽  
Test Results ◽  
Steam Turbines ◽  
Primary Flow ◽  
Flow Meters

One of the most significant contributors to the overall uncertainty of a performance test of a combined cycle steam turbine is the uncertainty of the primary flow measurement. ASME performance test codes provide many alternative methods for determining flow. In two actual combined cycle tests performed in 2005, the following three alternate methods were used to determine the HP steam flow into the combined cycle steam turbines: 1) Derivation from measured HP feedwater flow using calibrated PTC 6 throat tap nozzles, 2) Derivation from LP condensate using calibrated PTC 6 throat tap nozzles, and 3) Derivation from LP condensate using calibrated orifice metering sections. This paper describes the design, calibration, and installation of each flow meter involved, the methods used to calculate the HP steam flow, the estimated uncertainty of the HP steam flow derived using each method, and the actual test results using each method. A comparison of the methods showed that there are distinct advantages with one of the methods and that very low uncertainties in HP steam flow can be achieved if sufficient attention is applied to the design, calibration, and installation of all flow meters involved.

Calibration Uncertainty of PTC-6 Flow Sections

2006 ◽  
Author(s):  
James B. Nystrom ◽  
Philip S. Stacy
Keyword(s):  
Flow Measurement ◽  
Performance Test ◽  
Rate Of Change ◽  
Steam Turbines ◽  
Flow Meters ◽  
Average Value ◽  
Calibration Uncertainty ◽  
Primary Measurement ◽  
Performance Specifications ◽  
Weighing Method

PTC 6-2004 Performance Test Code on Steam Turbines [1] delineates fabrication and calibration requirements for throat tap flow nozzles with the purpose of obtaining the best feasible accuracy of flow measurement, a primary measurement to determine turbine performance. The Code requires nozzle discharge coefficient calibration results meet tight specifications for average value and rate of change with throat Reynolds number. Performance specifications were developed from large historical, empirical bases and an extensive theoretical analysis. Calibration uncertainty for PTC-6 Flow Meters using gravimetric flow measurement method in accordance with ASME/ANSI MFC 9M Measurement of Liquid Flow in Closed Conduits by Weighing Method [2] using a 100,000 lb capacity weigh tank is estimated. Calibration results are compared to Code requirements for about 330 meters with 1320 individual tap sets.

A Generalized Discharge Coefficient for Differential Pressure Type Fluid Meters

1974 ◽  
Vol 96 (4) ◽  
pp. 440-448 ◽  
Author(s):  
R. P. Benedict ◽  
J. S. Wyler
Keyword(s):  
Discharge Coefficient ◽  
Pipe Wall ◽  
Reynolds Numbers ◽  
Generalized Equation ◽  
Differential Pressure ◽  
Rational Basis ◽  
Flow Meters ◽  
Type Flow ◽  
New Formulation ◽  
Calibration Laboratories

A generalized rational equation is derived for the discharge coefficient of differential pressure-type fluid meters. Its factors are particularized for throat tap meters, pipe wall tap nozzles, and for orifice-type flow meters. Comparisons are made with available theories and with current Fluid Meter practices, and these support the new formulation. Because of its rational basis, the generalized equation may be useful for extrapolations to Reynolds numbers which lie beyond the capabilities of calibration laboratories.

Introduction of Improved Orifice Flow Measurement Methods in ASME PTC 19.5

2005 ◽  
Author(s):  
David R. Keyser ◽  
Jeffrey R. Friedman
Keyword(s):  
Flow Measurement ◽  
Discharge Coefficient ◽  
Performance Test ◽  
Dynamic Theory ◽  
Fluid Dynamic ◽  
Theoretical Concept ◽  
Flow Metering ◽  
New Information ◽  
Orifice Flow ◽  
Coefficient Of Discharge

This paper presents the new information on orifice flow metering in ASME Performance Test Code (PTC) 19.5, “Flow Measurement” [1], and discusses many of the clarifications that have been made based on experience and commentary to the review drafts of the Code. In particular, this paper expounds upon details regarding piping installation requirements for accurate measurement. A major advancement incorporated into ASME PTC 19.5 is the development of a coefficient of discharge equation that is based on fluid dynamic theory. The theoretical concept and a summary of the derivation of the new discharge coefficient equation for orifices are presented in this paper. It is shown that the calibration interpretation methodology introduced in PTC 19.5, which is similar to that developed earlier for nozzle calibrations, reduces the uncertainty of calibrated orifice metering sections, even when used outside the calibration range.

Velocity Profiles of Liquid Flow Through Circular Tubes and How They Affect Flow Measurement

1991 ◽  
Vol 113 (3) ◽  
pp. 206-210 ◽  
Author(s):  
D. Yogi Goswami
Keyword(s):  
Transition Region ◽  
Laser Doppler Velocimetry ◽  
Flow Measurement ◽  
Velocity Profiles ◽  
Turbulent Regime ◽  
Flow Meters ◽  
Circular Tubes ◽  
Flow Through ◽  
Hydrogen Bubble Technique

This paper analyzes velocity profiles for flow through circular tubes in laminar, turbulent, and transition region flows and how they affect measurement by flow-meters. Experimental measurements of velocity profiles across the cross-section of straight circular tubes were made using laser doppler velocimetry. In addition, flow visualization was done using the hydrogen bubble technique. Velocity profiles in the laminar and the turbulent flow are quite predictable which allow the determination of meter factors for accurate flow measurement. However, the profiles can not be predicted at all in the transition region. Therefore, for the accuracy of the flowmeter, it must be ensured that the flow is completely in the laminar regime or completely in the turbulent regime. In the laminar flow a bend, even at a large distance, affects the meter factor. The paper also discusses some strategies to restructure the flow to avoid the transition region.

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