Experimental Study of Vacuum Transport in a Horizontal 50-Millimeter Pipe.

摘要

A research program is to develop a physically sound design model for shipboard vacuum sewers. This report covers a series of experiments dealing with flow in a horizontal 50-mm pipe. The test facility and instrumentation are described, with emphasis on the accuracy of the various transducers. The performance characteristics of an ejector vacuum pump are quantified. The variation of vacuum with space and time is discussed and related to the pattern of flow as revealed by high speed video recording. Large vacuum drops are found to be related to the transitory formation of slugs which bridge the pipe bore. Vacuum sewer flow appears to be a chaotic dynamical system. Profiles of time average vacuum are related to controllable parameters such as flush volume and frequency and are compared with the homogeneous and Lockhart-Martinelli head loss models. A correlation for the volume of air admitted in a single flush is proposed. The report closes with conclusions and recommendations for further work. Keywords: Vacuum sewers, Vacuum collection, Two-phase flow, Sewage collection, Wastewater collection. (JHD)