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| Energy distribution and statistic characteristics in round water jet |
| Kang Can， Yang Minguan, Zhang Feng, Gao Bo |
| (School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China) |
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Abstract Under jet pressures of 13, 15 and 17 MPa, experiments were conducted by using Phase Doppler Particle Analyzer(PDPA) to measure axial mean velocity, axial fluctuating velocity and droplet diameter in the free water jet flows. Velocity of single droplet and corresponding droplet amount were statisticallyanalyzed when those droplets passed through the predefined measuring volumes at different positions in the three jet streams. Energy distribution in the free water jet flows was expected to be described consequently. The results indicate that distributions of axial velocity are rather similar for the five studied sections under the same jet pressure. Large gradient of axial velocity occurs at the jet rim. Maximum axial root mean square(RMS) velocity appears at the jet rim and overall axial RMS velocity increaseswith the jet pressure. Droplets with high velocity are predominant in central measuring volumes. However, the droplets passing through the rim measuring volumes are characterized by a wide velocity range. Different variation tendencies of statistical relation are proved at different sections when jet pressurechanges. Within the first sampling period, there is slight difference of the amount of the droplets passing through central measuring volumes. However, at rim measuring volumes, variations of droplet amountwith jet pressure and location of sampling section are remarkably irregular.
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Received: 08 May 2010
Published: 30 March 2011
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