Gas dynamics and heat-and-mass transfer in multistage steam jet pumps with intermediate condensers

Abstract

To specify the gas dynamics physical model and the design methods for ejectors, as well as the intermediate coolers functioning features, a range of complications has been formulated. It has been proven that the coefficient defining the critical section position of the secondary stream and characterizing the entrainment ratio of the ejector first stage depends on the characteristics of "a sound pipe" zone. Within this zone the velocity of the secondary stream can exceed sonic speed while the shock waves in the primary stream decrease. The optimum axial dimensions of the ejector are determined by the characteristics of "a sound pipe". The experimental investigations results reveal that the flow rate portion of steam condensed in the first stage cooler is about 70-80% of the full flow rate of steam entering the cooler and virtually doesn't depend on the air content in steam. The cooler efficiency depends on steam pressure, which is determined by the performance of the subsequent stage ejector and also by the cooling water temperature and flow rate.