Abstract: A hydrocarbon presence sensor used to detect for the presence of a fuel in a buffer cavity of an inter-propellant seal. A sensor is formed on a rotor shaft in the buffer cavity and an optical imaging device is used to view a change in appearance of the sensor when a hydrocarbon forms on the surface. The sensor is formed from either an oil/fuel leak detection powder or an oil colorimetric developer. A white light source or a laser is reflected off of the sensor and an optical imaging device reads the reflected light to detect for a change in color or intensity of the light to indicate if a hydrocarbon is present on the sensor surface.

Abstract: A cryogenic turbo-pump with an inducer and a system for detecting an onset of cavitation at the blade tips of the inducer. An IR imaging sensor is used to view the blade tips during operation of the turbo-pump for a temperature drop that indicates the onset of cavitation. The imaging sensor includes a means to vary the image capture rate to that the rotating blade tip will appear to be stationary in order to measure the blade tip temperature. A window is formed in the inducer housing in which the imaging sensor can view the blade tips during operation.

Abstract: A process for sizing an axial length of a throat in a jet pump, where an exponential relationship between mixing and kinetic energy dissipation of the primary jet is plotted in terms of a non-dimensional parameter on a graph which ranges from around 1.0 at an axial length of zero to a ratio of less than 0.1 at the minimal axial length of the throat to produce complete mixing between the primary and secondary fluids. This non-dimensional parameter is referred to as the Stein number.

Abstract: A Helmholtz resonator is used to detect a presence of a two-phase flow in a conduit. The resonator is sized so that a range of frequencies it is tuned for corresponds to a change in the speed of sound as the fluid changes from all liquid, to liquid plus vapor, and to all vapor. A band-pass filter is used to cancel out any external noise that would pollute the signal from the resonator. The resonator is used to monitor for a two-phase flow occurring within a feed line leading into a turbopump of a rocket engine.

Abstract: A hydrocarbon presence sensor used to detect for the presence of a fuel in a buffer cavity of an inter-propellant seal. A sensor is formed on a rotor shaft in the buffer cavity and an optical imaging device is used to view a change in appearance of the sensor when a hydrocarbon forms on the surface. In one embodiment, the sensor is a coating of porous silicon. In other embodiments, the sensor can be a mirrored or frosted surface on the shaft. A white light source or a laser is reflected off of the sensor and an optical imaging device reads the reflected light to detect for a change in color or intensity of the light to indicate if a hydrocarbon is present on the sensor surface.

Abstract: A process for determining a fluid flow velocity and then a mass flow rate of a cryogenic fluid in which a Helmholtz resonator is used to detect a presence of a two-phase flow in a conduit. The process first measures a frequency of the fluid flow, then determines a speed of sound of the fluid from the frequency, then measures the temperature of the fluid flow, and from the speed of sound and the temperature determines a quality of the fluid flow (liquid or vapor), and from the frequency and the fluid quality determines a Strouhal Number. The fluid flow velocity is found from an equation relating the frequency and a diameter of the surface area to the Strouhal Number. The mass flow rate is found from the fluid flow velocity and the temperature.