AC-2334 -- Fan Test Chamber-Nozzle Coefficients PDF

In the heating and ventilating industry, nozzles have peen used in conjunction with chambersfor laboratory air flow measurements at least since 1930, when "The Standard Code for Testingand Rating Steam Units Heaters" was published by the American Society of Heating andVentilating Engineers. This combination has developed into a very precise and versatilemethod of laboratory testing. Flow nozzles are less sensitive to extraneous factors thanmost other flow measuring devices, have a limited range of discharge coefficients, nearunity, for a wide range of flows, and can measure the total flow with one reading. The useof chambers eliminates the need for long duct runs, provides a compact and flexible testsystem, and can simulate a free space for the machine under test.