Comparison of wall pressure fluctuations in turbulent single and two-phase flows.

A closed two phase flow loop system was designed and constructed to measure the statistical properties of wall pressure such as RMS values, power spectral density and axial lateral cross correlations. In this loop, the two phase flow entered a straight run of smooth plastic pipeline (PVC) having an inside diameter of 8 inches, achieving at the test section a maximum Reynolds number in the order of 2 x 10 SUP 6 on a liquid basis. Measurements of the wall pressure fluctuations in a tubulent dispersed two phase flow were conducted using miniature semi conductor pressure transducers mounted flush with the internal surface of the rigid thick wall pipe working test section. It is important to mention that higher void fraction values (maximum void in experiments was 0.80) result in diminishing the mixture velocity and the intensity of the pressure fluctuations. Axial and lateral correlations have shown dependence upon the flow quality (volumetric mixing ratio). (A)