E. von Lavante, M. Ishibashi, G. Wendt
Detailed investigation of flow fields assocciated with several sonic Venturi nozzles with small Reynolds numbers used for flow metering was carried out. The range of Reynolds numbers considered in this work extended from 4 × 10 3 to 4.4 × 10 4 . In the experimental part, global parameters such as discharge coefficient C d and local flow variables such as recovery temperature T r were investigated independently at two different scientific institutions. Both discovered flow phenomena that were not explainable using simple linear theories. Therefore, in the numerical part of the present...
G. Wendt, E. von Lavante
The paper describes the results of experiments carried out with a set of 50 critical Venturi nozzles with diameters between 0.15 mm and 10 mm with special emphasis on small nozzles with diameters of less than 1 mm. All nozzles were shaped in accordance with the current ISO Standard 9300, only the quality of surface finish having average roughness heights between 0.1 mm and 1 mm differed from the requirements of this standard. The present investigations contain the determination of common relations used to characterize critical flow through Venturi nozzles and their dependence on surface...
E. von Lavante, A. Zachcial, D. Zeitz, B. Nath, H. Dietrich
Numerical analysis of flow fields associated with sonic Venturi nozzles with various modifications of its basic geometry was carried out. The baseline nozzle, used for gas flow metering, was simulated at Reynolds number 1.5 × 10 5 . The modifications included a backward facing step in the nozzle wall just after the throat, suction through the wall and three different diffuser opening angles. The flow was simulated using compressible viscous flow solver ACHIEVE developed by the authors. ln some cases, a noticable improvement in the flowrate and, consequently, increase in the discharge...
P. Schley, E. von Lavante, D. Zeitz, M. Jaeschke, H. Dietrich, B. Nath
Critical nozzle flow is predicted for high pressure natural gas by way of numerical simulation. The CFD-program used was developed for simulating two- dimensional and axially symmetric, viscous flow. The thermodynamic properties significantly affecting nozzle flow of high pressure natural gas were computed using the AGA8-DC92 equation of state. To verify the present theoretical results, mass flow measurements of natural gas were made using the Pigsar high-pressure test rig. A comparison between theoretical and experimental results is presented for one test case.
J. P. Vallet, C. Windenberger, F. Vulovic, R. Bouard
Nozzles operating under sonic conditions are already used widely as reference flowmeters in many countries to measure gas flow rate under pressure. These Nozzles are calibrated, in each of the countries concerned, on approved primary test rigs. The techniques used in these countries today are the fruit of R&D carried out on nozzles for more than twenty years. The outcome has been standard ISO 9300, published in 1990, on the technique for measuring gas flowrates using a sonic nozzle. In the past years, it was decided to revise the ISO 9300 in order to improve the values of the thermodynamic...
K. A Park, Y. M. Choi, H. M. Choi, T. S. Cha, B. H. Yoon
Small sonic nozzles (throat diameter 0.28 4.48 mm) were tested in the gas flow standard system. This standard system is composed of two bell provers and 5 column piston provers, compressor, filters, and dehumidifier. The discharge coefficients of small sonic nozzles are obtained and correlated as a function of throat Reynolds numbers with 0.33 % uncertainty at a confidence level 95 %. The tested high Reynolds number was the lower limit of ISO 9300 specifications. The data are useful as data base for revision of ISO 9300.
H. Dietrich, B. Nath, E. v. Lavante, M. Jaeschke, P. Schley , H.-J. Hotze
A new CEN-Standard for gas flow meters requires meters, which working at operating pressures of more than 4 bar to be calibrated accordingly. However in this pressure range, and especially for small flow rates, only a few suitable test rigs exist world-wide. Based on the good experience with sonic nozzles for air at atmospheric conditions, their use for the calibration of gas flow meters in high pressure natural gas is anticipated. The present paper presents a novel concept for the design and usage of sonic nozzles in high pressure natural gas test rigs. It is based on theory, simulation and...
S. Silva, K. Kawakita, M. T. Pereira, M. Cattani, M. C. Salvadori
A process to manufacture diamond sonic micronozzle has been described. Tungsten wires was used as a mold to make diamond microtubes. A pretreatment of the wire surface with diamond powder provided a continuous diamond film deposited by Chemical Vapor Deposition. An acid etching of the tungsten was performed to remove the mold, obtaining a cylindrical diamond micronozzle.
Paulo J. S. Jabardo, Kazuto Kawakita
This paper presents a numerical investigation of critical flow in small cylindrical orifices. Microorifices with diameters ranging from 16 to 423mm with length to diameter ratios (L/D) ranging from 0,6 to 16 were simulated using a numerical solver. Flow simulations were carried out under several back to upstream pressure ratios ( P b / P 0 ) under pressurized (increasing upstream pressure P 0 ) and vacuum (decreasing back pressure P b ) modes of operation. Numerical results were validated by comparing calculated flow rates with experimental data. This comparison showed a good agreement...
Luciana Casciny, Nilson Massami Taira
This article describes the Flow Laboratory necessities for a new facility, and how to extend the calibration flow rate using a meter with no moving parts, easy to operate and with low uncertainty. The proposal alternative is using two meters in parallel as the working standard: one sonic nozzle and one rotary piston (CVM) its the measurement uncertainty and some results.