Measurement of the Incident Sound Power in Ducts and Effect Factors Analysis

Abstract

Based on two-microphone transfer function method, the measuring method of incident sound power in duct is introduced, The special test equipment is built, and the test and measurement program of incident sound power in duct is written, and effect factors of measurement are analyzed. Results are shown that temperature, flow velocity, microphone spacing deviation and complex reflection coefficient influences less on the program. Transmission loss of perforated tube muffler with no flow is measured using the program, comparison is carried out with results of finite element method, they agrees with well, and with flow sound power of flow regeneration from the muffler is also done, an important foundation is provided for quantitative study on occurring mechanism flow regenerated noise and enhancing attenuation performance of muffler.