In cryogenic fluid cavitation phenomenon is similar to boiling. Generally, these two processes can be distinguished by the fact that cavitation is the process of nucleation in a liquid when the pressure falls below the saturated vapor pressure, while the boiling is the process of nucleation that occurs when the temperature is raised above the saturated vapor temperature. In cryogenic fluids is very difficult to distinguish between these two different causes of phase change, and a lack of experimental investigations is present in literatures. In aerospace field, cryogenic fluids are usually used as rocket propellant obtained as mixture of liquid oxygen (LOx) and liquid hydrogen (LH2). These fluids can be employed under particular conditions as low temperature, microgravity and the environmental space, but they are susceptible to cavitation phenomena, because to a few change of temperature is combined to a change of phase. The aim of this paper is to examine the results of a flow visualization study on two-phase cryogenic flow passing through a internal nozzle. The transient growth process of the cloud cavitation induced by flow through the throat is observed using high-speed video images and analyzed by pressure and accelerometer signal.
Flow Visualization Study on Two-Phase Cryogenic Flow
DE GIORGI, Maria Grazia;FICARELLA, Antonio;RODIO, MARIA GIOVANNA;LAFORGIA, Domenico
2008-01-01
Abstract
In cryogenic fluid cavitation phenomenon is similar to boiling. Generally, these two processes can be distinguished by the fact that cavitation is the process of nucleation in a liquid when the pressure falls below the saturated vapor pressure, while the boiling is the process of nucleation that occurs when the temperature is raised above the saturated vapor temperature. In cryogenic fluids is very difficult to distinguish between these two different causes of phase change, and a lack of experimental investigations is present in literatures. In aerospace field, cryogenic fluids are usually used as rocket propellant obtained as mixture of liquid oxygen (LOx) and liquid hydrogen (LH2). These fluids can be employed under particular conditions as low temperature, microgravity and the environmental space, but they are susceptible to cavitation phenomena, because to a few change of temperature is combined to a change of phase. The aim of this paper is to examine the results of a flow visualization study on two-phase cryogenic flow passing through a internal nozzle. The transient growth process of the cloud cavitation induced by flow through the throat is observed using high-speed video images and analyzed by pressure and accelerometer signal.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
