Turbopump radial and axial rotor support system

Design of thrust balancer minimizes leakage bypass and obviates need for conventional thrust balancer. System allows operation at low flow rates and high thrust capacity at cryogenic temperatures and high pressures

Orbital transfer vehicle oxygen turbopump technology. Volume 1: Design, fabrication, and hydrostatic bearing testing

The design, fabrication, and initial testing of a rocket engine turbopump (TPA) for the delivery of high pressure liquid oxygen using hot oxygen for the turbine drive fluid are described. This TPA is basic to the dual expander engine which uses both oxygen and hydrogen as working fluids. Separate tasks addressed the key issue of materials for this TPA. All materials selections emphasized compatibility with hot oxygen. The OX TPA design uses a two-stage centrifugal pump driven by a single-stage axial turbine on a common shaft. The design includes ports for three shaft displacement/speed sensors, various temperature measurements, and accelerometers

Orbital transfer vehicle oxygen turbopump technology. Volume 2: Nitrogen and ambient oxygen testing

The testing of a rocket engine oxygen turbopump using high pressure ambient temperature nitrogen and oxygen as the turbine drive gas in separate test series is discussed. The pumped fluid was liquid nitrogen or liquid oxygen. The turbopump (TPA) is designed to operate with 400 F oxygen turbine drive gas which will be demonstrated in a subsequent test series. Following bearing tests, the TPA was finish machined (impeller blading and inlet/outlet ports). Testing started on 15 February 1989 and was successfully concluded on 21 March 1989. Testing started using nitrogen to reduce the ignition hazard during initial TPA checkout. The Hydrostatic Bearing System requires a Bearing Pressurization System. Initial testing used a separate bearing supply to prevent a rubbing start. Two test series were successfully completed with the bearing assist supplied only by the pump second stage output which entailed a rubbing start until pump pressure builds up. The final test series used ambient oxygen drive and no external bearing assist. Total operating time was 2268 seconds. There were 14 starts without bearing assist and operating speeds up to 80,000 rpm were logged. Teardown examination showed some smearing of silverplated bearing surfaces but no exposure of the underlying monel material. There was no evidence of melting or oxidation due to the oxygen exposure. The articulating, self-centering hydrostatic bearing exhibited no bearing load or stability problems. The only anomaly was higher than predicted flow losses which were attributed to a faulty ring seal. The TPA will be refurbished prior to the 400 F oxygen test series but its condition is acceptable, as is, for continued operating. This was a highly successful test program

Inducer dynamics full-flow, full-admission hydraulic turbine drive Interim report for tasks 1, 2, and 3

Hydrodynamical and mechanical design layout for two-speed hydraulic turbine inducer, computer simulation of pumping system and test facility performance, and study of demonstration uni

Implementing a hybrid space discretisation within an agent based evacuation model

Egress models typically use one of three methods to represent the physical space in which the agents move, namely: coarse network, fine network or continuous. In this work, we present a novel approach to represent space, which we call the ‘Hybrid Spatial Discretisation’ (HSD), in which all three spatial representations can be utilised to represent the physical space of the geometry within a single integrated software tool. The aim of the HSD approach is to encompass the benefits of the three spatial representation methods and maximise computational efficiency while providing an optimal environment to represent the movement and interaction of agents

Covalent flavinylation of L-aspartate oxidase from Escherichia coli using N6-(6-carboxyhexyl)-FAD succinidoester

L-Aspartate oxidase is a flavoprotein catalyzing the first step in the de novo biosynthesis of pyridine nucleotides in E. coli. Binding of FAD to L- aspartate oxidase is relatively weak (K(d) 6.7 x 10-7 M), resulting in partial loss of the coenzyme under many experimental conditions. Only the three-dimensional structure of the apo-enzyme has been obtained so far. In order to probe the flavin-binding site of the enzyme, apo-L-aspartate oxidase has been reacted with N6-(6-carboxyhexyl)FAD succinimidoester. The structural characterization of the resulting N6-(6-carbamoylxyhexyl)FAD-L- aspartate oxidase shows the covalent incorporation of 1 FAD-analog/monomer. Residue Lys38 was identified as the target of the covalent modification. N6- (6-carbamoylxyhexyl)-FAD-L-aspartate oxidase shows only 2% catalytic activity as compared to the native enzyme. Comparison of some properties of the flavinylated and native enzymes suggests that, although the flavin is covalently bound to the former in the region predicted from molecular modeling studies, the microenvironment around the isoallossazine is different in the two forms

Covalent flavinylation of L-aspartate oxidase from Escherichia coli using N6-(6-carboxyhexyl)-FAD succinimidoester.

L-Aspartate oxidase is a flavoprotein catalyzing the first step in the de novo biosynthesis of pyridine nucleotides in E. coli. Binding of FAD to L-aspartate oxidase is relatively weak (K(d) 6.7 x 10(-7) M), resulting in partial loss of the coenzyme under many experimental conditions. Only the three-dimensional structure of the apo-enzyme has been obtained so far. In order to probe the flavin-binding site of the enzyme, apo-L-aspartate oxidase has been reacted with N6-(6-carboxyhexyl)-FAD succinimidoester. The structural characterization of the resulting N6-(6-carbamoylxyhexyl)FAD-L-aspartate oxidase shows the covalent incorporation of 1 FAD-analog/monomer. Residue Lys38 was identified as the target of the covalent modification. N6-(6-carbamoylxyhexyl)-FAD-L-aspartate oxidase shows only 2% catalytic activity as compared to the native enzyme. Comparison of some properties of the flavinylated and native enzymes suggests that, although the flavin is covalently bound to the former in the region predicted from molecular modeling studies, the microenvironment around the isoallossazine is different in the two forms