The New Semi-Experimental Method for Simulation of Turbine Flow Meters Rotation in the Transitional Flow
The new semi-experimental method for simulation of the turbine flow meters rotation in the transitional flow has been developed. The method is based on the experimentally established exponential low of changing of dimensionless relative turbine gas meter rotation frequency and meter inertia time constant. For experimental evaluation of the meter time constant special facility has been developed. The facility ensures instant switching of turbine meter under test from one channel to the other channel with different flow rate and measuring the meter response. The developed method can be used for evaluation and predication of the turbine meters response and dynamic error in the transitional flow with any arbitrary law of flow rate changing. The examples of the method application are presented. Keywords—Dynamic error, pulsing flow, numerical simulation, response, turbine gas meters.
Pulsation effects on single- and two-rotor turbine meters
Abstract The natural gas industry is particularly in need of a technology and a method which will assis tin identifying pulsation-related problems at field measurement sites. This paper describes results of a research programme sponsored by the Gas Research Institute (GRI) which has investigated the response of single- and two-rotor turbine meters to pulsations and has identified a practical diagnostic technique which may meet industry's needs. Both single- and two-rotor turbine meters have been tested in the GRI Meeting Research Facility (MRF) in pulsating flow over a range of frequencies and amplitudes typical of those seen in gas industry applications. The pulsation frequencies and amplitudes cover the normal field conditions with velocity modulations from a few to 20% of the mean flow rate. Flow rates investigated in the 100 mm test meters include from 15% to nearly 100% of the meter's capacity. Test results show that pulsation modes which produce a strong velocity modulation at the meter have the most influence on measurement accuracy, while pressure pulsation amplitude at the meter has little influence. Furthermore, results show that pulsations which influence meter registration also affect rotor speed in a detectable manner. It has been demonstrated that by monitoring modulation of the time period between turbine rotor pulses, a measurement can be derived to detect the presence of pulsations and identify the frequency and, potentially, the amplitude of pulsation-induced errors.
Step response tests on turbine flowmeters in liquid flows
Abstract The existing analysis of the response of small turbine flowmeters in liquid flows to step changes in flow shows a strong influence of the requirements of conservation of angular momentum. An apparatus is described for the experimental measurement of the step response. The results show that the existing analysis is not an adequate description of the response. An explanation of the experimental response is given. Stop (step to zero) tests are also described and are used to assist in the explanation of the meter response.