On the Transient Behavior of Oil Flow under Negative Pressure

Abstract

The transient behavior of oil flow under negative pressure is studied experimentally. To observe the negative pressure, three types of pipe models with different boundary conditions are used. The pipe used in experiment is 20 m in length, and 8 mm or 12 mm in diameter. Quick operation of a valve mounted at the end of pipe causes fluid transients. The negative pressure is measured mainly using strain gauges set on the outer surface of the pipe. By applying the principle of pressure difference meter, the relation between strain and negative pressure was tested equivalently. The negative pressure below absolute zero was observed experimentally. The numerical computation by means of characteristics method showed a good agreement with the experimental results. The condition of inner surface of the pipe has a great influence on the transient behavior under negative pressure.