Accuracy Analysis of Code-Test Flow Measurements

Author(s):  
David R. Keyser

Analysis and estimation of uncertainty is presented for several typical Code-test situations for PTC-approved, differential pressure, flow-measurement systems. These analyses trace the calibration pedigree from the fundamental standards at NIST to the implementation of the instrumentation at the test site.

Author(s):  
Takatsugu Miura ◽  
Kingo Igarashi ◽  
Tomoyuki Hosaka ◽  
Takumi Kitagawa ◽  
Tatsurou Yashiki ◽  
...  

Abstract In power plants that becoming more compact, it will expend much time and effort to satisfy the requirement for the differential pressure flow measurement according to ISO’s standards. Therefore, it is difficult for engineers in the design phase to completely remove the potential for large errors in flow measurement. This paper presents the 3D fluid analysis system that is a lower cost than the conventional method to confirm the soundness of such measurement in the phase of piping route design. This system has the function to automatically generate the analysis models from general 3D piping CAD data. The analysis program is written by the open source code to reduce a license fee. Also, this system has the function of calculating the swirl strength along the pipe axis as one of the means for efficiently supporting the design change. In order to verify and validate the analysis system, we analyzed several flow paths, confirmed the response of the swirl strength and flow rate indication value of the differential pressure flowmeter model. The analysis result well simulated the increase or decrease swirl strength in the complex flow path, and fluctuation of the flow rate indication value. Also, the system supports to set the flowmeter in the appropriate position by providing visualization of the swirl strength along the pipe axis. In the flow path analysis in this validation, it took about one month to visualization of the swirl strength along the pipe axis from the generation of the analysis models. The 3D fluid analysis system collaborative with 3D piping CAD design system has been developed. This system enable to confirm the effects of swirl strength on flow measurement and the soundness of the differential pressure flow measurement at a lower cost in comparison with conventional method.


Author(s):  
Anatoly Kusher

The reliability of water flow measurement in irrigational canals depends on the measurement method and design features of the flow-measuring structure and the upstream flow velocity profile. The flow velocity profile is a function of the channel geometry and wall roughness. The article presents the study results of the influence of the upstream flow velocity profile on the discharge measurement accuracy. For this, the physical and numerical modeling of two structures was carried out: a critical depth flume and a hydrometric overfall in a rectangular channel. According to the data of numerical simulation of the critical depth flume with a uniform and parabolic (1/7) velocity profile in the upstream channel, the values of water discharge differ very little from the experimental values in the laboratory model with a similar geometry (δ < 2 %). In contrast to the critical depth flume, a change in the velocity profile only due to an increase in the height of the bottom roughness by 3 mm causes a decrease of the overfall discharge coefficient by 4…5 %. According to the results of the numerical and physical modeling, it was found that an increase of backwater by hydrometric structure reduces the influence of the upstream flow velocity profile and increases the reliability of water flow measurements.


Author(s):  
Meri L. Andreassen ◽  
Bonnie E. Smith ◽  
Thomas W. Guyette

Pressure-flow data are often used to provide information about the adequacy of velopharyngeal valving for speech. However, there is limited information available concerning simultaneous pressure-flow measurements for oral and nasal sound segments produced by normal speakers. This study provides normative pressure, flow, and velopharyngeal orifice area measurements for selected oral and nasal sound segments produced by 10 male and 10 female adult speakers. An aerodynamic categorization scheme of velopharyngeal function, including one typical category and three atypical categories (open, closed, and mixed) is proposed.


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