Comparison of 10% CO2-N2 and 5% CH4-Ar gas mixture as a make-up of gas chromatography with electron capture detection (GC-ECD) for the measurement of sulfur hexafluoride (SF6) was investigated. It was found that 10% CO2-N2 shows the make-up characteristic comparable to 5% CH4-Ar. Thus, 10% CO2-N2 is considerable as an alternative to 5% CH4-Ar.
A new methodology for designing the differential pressure flowmeters for fluid energy carriers has been developed in order to provide the minimum uncertainty of flowrate measurement results. This methodology is implemented in “Raskhod-RU” CAD system for the computer aided design and calculation of differential pressure flowmeters. “Raskhod-RU” CAD meets the requirements of new Standards (DSTU GOST 8.586.1,2,3,4,5-2009 and GOST 8.586.1,2,3,4,5-2005).
The temperature of a transducer sensitive element, as a result of its heat capacity, will always lag behind the temperature of the gas flow if this temperature changes. When measuring the flow temperature that varies in time, the transducer doesn't follow the changes in temperature immediately because its sensitive element temperature changes after some time. The distortions of the transducer readings are caused by the thermal inertia due to non-stationary heat processes in the transducers, as well as between transducer and the environment.
The main types of errors which occur while measuring the temperature of gas flows, including flows of fuels, are determined by the conditions of thermal balance at the interaction of the sensor of the temperature transducer (TT) with the gas flow via convection, radiation and conduction. The limited TT capacity to track flow temperature variation should also be taken into consideration. For high gas flow speeds (over 50 m/s), another type of error (the so-called speed error) arises from the transformation of part of kinetic energy of the flow into thermal energy.
Nowadays, industrial development creates new and more complex processes leading to emergence of specific conditions for use of sensors and therefore specific measurement tasks. These circumstances lead to new requirements both for the methods of measurement and for sensors that implement these methods. Developments in microelectronic technologies and materials science have led to a significant number of types of pressure sensors.
This work deals with the investigation of influence of flow pulsation on the accuracy of gas flowrate and volume measurement by means of the differential pressure flowmeters. Experimental studies of the step response curves of an impulse line with a pressure transducer (PT) were carried out with application of a high-frequency analog-to-digital converter of the pressure signal in the PT chamber. Mathematical model of an impulse line with a PT was built. This model provides simulation and investigation of the transient processes with high accuracy.
Nowadays the problem of quick-changing non-stationary values measurement is extremely actual in various modern technical systems (parameters control of engine combustion chamber, testing of aerospace complex products, scientific researches etc.). There are sufficiently effective ways of such measurement. However, increase in the speed of such methods is needed urgently. The attempt of finding the new approach to the problem of sensor output signal processing when measuring non-stationary values using the example of non-stationary pressure measurement by piezoresistive sensors is presented.