AIR FLOW MEASUREMENTS IN A URGE IRREGULARLY SHAPED TUNNEL USING ANEMOMETER AND PITOT-STATIC TUBE TRAVERSES

摘要

A series of traverses using anemometers and pitot tubes to measure the flow rate of air through an explosion gallery were carried out. Flow rates were also measured using a conical inlet fitted at the gallery outlet. Good agreement was found between the flow rates measured by the individual traverses, but these invariably gave a lower flow rate than the conical inlet, the average difference being about 6%. No definite explanation for this could be found, but conditions in the gallery could possibly cause the inlet to be read in error, although it did not show in subsequent scale model tests. Several methods of traversing the gallery were then used and a system for locating the measuring positions in such irregularly shaped ducts is proposed; these methods did not produce significantly different results, except for a 'continuously sweeping' method which gave flow rates higher than the others by about 2%. In an auxiliary study, it was shown that, unless great care is taken, serious errors can arise in anemometer calibrations.