Investigation of Operating Conditions for Development of an Ultra-Micro Steam Injector

Abstract

A steam injector (SI) works as a passive jet pump and has high heat transfer performance due to direct contact condensation between steam flow and subcooled water jet. The objective of the present study is to clarify heat transfer and flow characteristics of an ultra-micro steam injector (UMSI) with throat diameter of 1.0 mm. To this end, internal flow was visualized by a high-speed video camera. Pressure and temperature were measured with the visualization simultaneously. The main parameters were inlet steam pressure, inlet water flow rate and inlet water temperature. As a result, the formation of the water jet was confirmed. In that case, it was verified that discharged pressure became higher than the inlet pressure. The UMSI was successfully operated by achieving simultaneous maintenance of water jet and boosting pressure. In addition, water cooling capacity and steam heating power were evaluated. The operable region was suggested to exist in the large water cooling capacity condition.