Cavitation in Simulated Cryogenic Liquids
We are currently studying the cavitation of cryogenic fluids through using a refrigerant fluid which is characterized by high ambient vapor pressure and accessible critical conditions to model the behavior of liquid hydrogen as it is passing through a low-pressure turbopump. The purpose of the research is to investigate the impact of the thermodynamic effect - the local cooling of the liquid around a vaporization zone - to establish cavitation prediction correlations for the near-critical regime. The test section cross-section is 10x10 cm and the predicted maximum freestream velocity is 10 m/s. The facility is fitted with a 7.5 kW immersion heater and can be maintained at absolute pressures of 0.2-5 atm, allowing cavitation at a wide range of conditions to be studied in several different media. As of May 2007, the water tunnel facility is operational and delivering pressure spectra and LIF results.
The water tunnel facility with its 25 hp pump.
The water tunnel test section with optical access from three directions and the rear access port used for holding the test object, e. g. a hydrofoil.
Hydrofoil with transparent cover mounted in the watertunnel. Using a 351 nm laser sheet projecting from the hydrofoil, fluorescence is produced by the fluoroketone.
The two NACA0015 hydrofoils used in the tests. Left: Pressure tap foil with 7 taps on suction side and 2 on pressure side, all along centerline. Right: Laser sheet access foil, allowing UV laser sheet to be injected along the centerline from the surface of the hydrofoil.
A separate experimental setup has been constructed to study the spectroscopic properties of the fluoroketone used as a test medium.