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ANGULAR FLOW INSENSITIVE PITOT TUBE SUITABLE FOR USE WITH STANDARD STACK TESTING EQUIPMENT
Citation:
Mitchell, W., B. Blagun, D. Johnson, AND M. Midgett. ANGULAR FLOW INSENSITIVE PITOT TUBE SUITABLE FOR USE WITH STANDARD STACK TESTING EQUIPMENT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/4-79/042 (NTIS PB80102007).
Description:
Five pitot tube designs were tested under various gas flow conditions for accuracy in measuring static and total pressure. The static- and impact-pressure measuring tubes least affected by angular flow were combined and then evaluated in the presence of standard particulate sampling nozzles. Tests were performed on 'S', 'L', Kiel and cylinder pitot tubes and a shielded static-pressure pitot tube. The percent error for each pitot tube was determined as a function of yaw, pitch, orifice size, orifice location, pitot tube size, and velocity. A pitot tube was developed that is accurate within 5% when yawed and pitched + or - 30 degrees even while attached to a standard EPA Method 5 sampling assembly. This pitot tube was field tested at a sewage sludge incinerator, a clay crushing plant and a power plant. Also included in the report are: a summary of the existing literature on design of 'L' pitot tubes; a summary of the present state-of-the-art in sampling stacks with cyclonic flow and the errors involved in such sampling; a recommendation for straightening cyclonic flow by insertion of a venturi throat; and the effect of Reynolds Number on pitot tube accuracy.