STP1181

    An Aqueous Fine Clean Process for Rocket Engine Hardware

    Published: Jan 1993


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    Abstract

    An aqueous fine clean process has been developed for large-scale, complex rocket engine hardware required to meet a cleanliness level of less than 10 mg/m2 (<1 mg/ft2) nonvolatile residue (NVR) and no particles greater than 400 μm in any dimension. The hardware must be compatible with oxygen over the parameter range of liquid oxygen at -160°C (-256°F) and 61 MPa (8800 psi) to gaseous oxygen at +704°C (+1300°F) and 31.5 MPa (4570 psi).

    The complete cleaning cycle is comprised of a preclean operation, fine clean, and verification. The aqueous fine clean process developed is a two step operation using a nonionic surfactant diluted in deionized water as a prerinse followed by a final rinse of fresh deionized water. A nonionic surfactant was selected to minimize corrosion and to meet current NASA specification requirements.

    The cleanliness of hardware surfaces in this study was determined by analyzing the effluent from flushing with ambient temperature 1, 1, 1-trichloroethane (TCA) in a 30 000 Class cleanroom. The particulate matter was determined by filtering the TCA using a 0.45 μm filter and the NVR was determined by gravimetric procedure. Oxygen compatibility was determined by testing in ambient pressure liquid oxygen at -160°C using an impact energy of 10 kg-m.

    Keywords:

    aqueous, ultrasonic, cleaning, surfactant, oxygen systems


    Author Information:

    Becker, JF
    Engineer, Rockwell International Corp., Canoga Park, CA

    Shoemaker, MC
    Engineer, Rockwell International Corp., Canoga Park, CA


    Paper ID: STP15954S

    Committee/Subcommittee: G04.01

    DOI: 10.1520/STP15954S


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