EFFECT OF NOZZLE LENGTH AND DIAMETER ON PLUME STABILITY AND NOISE IN DIRECT CONTACT CONDENSATION OF STEAM IN A SUBCOOLED CROSSFLOW OF WATER

Abstract

Direct Contact Condensation (DCC) transfers heat to a process fluid by directly injecting a high-pressure vapor into a subcooled liquid stream. Direct contact condensers have a smaller overall footprint compared to traditional heat exchangers and are used in several industries, including milk pasteurization, emergency cool-down in nuclear power plants, and wastewater treatment. During DCC, vapor is accelerated through small nozzles that generate vapor plumes that penetrate the process fluid. Under certain conditions, the vapor plume becomes unstable and can generate significant noise and vibrations. The goal of this study is to understand the effect of nozzle geometry on plume stability and noise when steam is injected into a crossflow water stream. In these experiments, we characterize the steam plume flow regime and noise level through single- and two-port nozzles. The results quantify the impact of water temperature (25 - 80°C), pressure ratio (0.47 and 0.58), nozzle diameter (1.65 – 3.18 mm), and the nozzle length-to-diameter ratio (1 – 8). This study shows that nozzles with a smaller diameter and smaller length-to-diameter ratio produce less noise and that two smaller holes can have the same mass flow rate (and heating) as one larger nozzle, but less noise.