Engineering topics
Publications and source records attributed to Daniel J Dorney.
A test program to characterize the solution of helium in nitrogen tetroxide/mixed oxides of nitrogen (NTO)/(MON) and monomethylhydrazine (MMH) at anticipated flight-representative pressures/temperatures was completed. Updated relations for helium solubility in MMH and NTO were generated and documented.
The NESC performed an assessment of existing filtration standards and guidance documents for propellant and pressurant systems. The assessment included a vendor survey to better understand concerns about filtration systems, defined a common set of filtration and contamination-related terms, and developed guidelines for system filtration design and implementation.
The NESC performed testing to determine if high-speed video techniques can be used to predict the onset of flow-induced vibrations (FIV) in bellows. A comprehensive test matrix was established to determine if Motion Magnification (MM) and Digital Image Correlation (DIC) can be used to determine the onset of FIV in straight and gimbaled bellows. Several of the tests were intended to determine if MM and DIC can establish the resonant frequencies of the bellows with no a priori knowledge. The results of the MM and DIC were compared with data from strain gages and microphones. Although the testing was limited to one single-ply unshielded bellows, this effort provided the proof-of-concept that MM and DIC are feasible methods for determining the onset of FIV in bellows.
Cavitation in liquid propulsion systems can lead to performance degradation and hardware failures. The NESC sponsored an investigation to measure and model cavitation in pressurized hydrogen peroxide fl ow. The experimentally measured and computationally predicted cavitation lengths were compared as a function of cavitation number. The measured and predicted data exhibited close agreement over the range of pressures and temperatures studied, and no calibration of the cavitation model coefficients was needed.
As part of a recent liquid rocket engine shutdown investigation, a commercial partner requested that NASA provide the autogenous ignition (or autoignition) temperature (AIT) of isopropyl alcohol (IPA). NASA provided the available data, but the data were somewhat scattered, likely due to test configuration and test technique differences. NASA Engineering and Safety Center (NESC) support was requested to experimentally determine the AIT of IPA and ethanol, both of which are extensively applied to propulsion systems. This report contains the outcome of the NESC assessment.
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