Specific mass flow rate measurements in a pulsating flow of gas

The method of measurement of the specific mass flow rate in a pulsating flow by means of the Constant Temperature Anemometer (CTA) has been described. Special attention has been paid to the probe calibration problem. Different forms of the CTA characteristic have been analyzed. Example measurement results have been presented for chosen pulse frequencies. Apart from the measurements executed in one single point representing each control section, a flow field survey has been done in order to determine the velocity profile under the conditions of a pulsating flow. Probes have been displaced radially with a small step to cover the range from the pipe axis to its wall. It has been found that in the large field around the pipe axis, successive velocity plots are similar as far as their shape and phase shift are considered. Pulsations are damped and mean velocity decreases rapidly only in direct proximity of the pipe wall. It has been also shown that the presence of pulsations makes the mean velocity profile more uniform than in the case of a steady flow. Measurements have been also performed for the case of a reverse flow occurring in the pipe at resonance frequencies.