Study on High Performance of Steam Injector (2nd Report, Measurement of Jet Structure)

Abstract

A steam injector is useful in various industries since it is a simple, compact and passive component. Steam injector performance depends on the phenomena of steam condensation onto the water jet surface and heat transfer in the water jet due to turbulent heat transfer. In order to develop high performance steam injector, it is necessary to clarify flow structure of two-phase jet. We carried out experiments to observe the internal behavior of the water jet as well as measure velocity and temperature. As soon as the steam injector starts up, the stable water jet formed in the center of mixing nozzle although it oscillated and the surface wave developed larger with distance due to large shear stress from high speed steam jet. It was confirmed that the steam was supersonic at the outlet of the steam nozzle and the measured velocity in the mixing nozzle was 400-490 m/s. The radial velocity and temperature distributions were obtained and they suggested that the similarity rule was applicable to the water jet in a steam injector as well as the turbulence flow in a circular pipe. It was concluded that the steam nozzle figure was one of the most important parameter for the performance of steam injector. Furthermore, the characteristic analysis model we have proposed evaluated well discharge pressure.