Development of the Vortex Mass Flowmeter with Wall Pressure Measurement

Abstract

Mass flow measurement is essential to the understanding and control of processes concerning fluid flow. The availability of reliable mass flowmeters, however, is far inadequate to meet the demand. In this paper we developed a practical vortex mass flowmeter with wall pressure measurement. The meter coefficient of mass flow rate was acquired through experiments with air at Reynolds numbers from 1.3×10 3 to 9.8×10 3 . Here we show that the meter coefficient of mass flow rate is nearly constant at Reynolds numbers greater than 5.5×10 3 . To further extend the lower limit, a correction factor related to the Reynolds number was introduced into the vortex mass flowmeter. The results show that the relative errors of the vortex mass flowmeter developed are basically within ±5%. This device can satisfy a diversity of requirements of mass flow measurement in engineering fields.

Investigations of Thermocouple Drift Irregularity Impact on Error of their Inhomogeneity Correction

“…Therefore, error of sensor is the biggest error among errors of other components of measurement channel [3][4][5]. The same situation is typical for other sensors [6,7].This fact calls for research of effective error decreasing methods.…”

“…For most of them the reliable methods of error correction are known. Like for the following components: (i) initial deviation of conversion characteristics (CC) of thermocouples from nominal [7]; (ii) significant deviation of CC during operation, which is connected with degradation of electrodes of thermocouples under influence of high temperature and operation time [5,[9][10][11]; (iii) error caused by cold junction effect, and so on [1,2,12].…”

A Formalism for Expressing the Probability Density Functions of Interrelated Quantities

“…But if the system is already in place, the same equations provide a means for measuring the volumetric flow rate Q through the duct. Thus, the mass flow rate Q m ρ = & can be obtained in an alternative manner to direct measurement, e.g., by a vortex mass flowmeter [12]. The volumetric flow rate is given by…”