Advanced tube-bundle rocket thrust chamber

An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction

Hot fire fatigue testing results for the compliant combustion chamber

A hydrogen-oxygen subscale rocket combustion chamber was designed incorporating an advanced design concept to reduce strain and increase life. The design permits unrestrained thermal expansion of a circumferential direction and, thereby, provides structural compliance during the thermal cycling of hot-fire testing. The chamber was built and test fired at a chamber pressure of 4137 kN/sq m (600 psia) and a hydrogen-oxygen mixture ratio of 6.0. Compared with a conventional milled-channel configuration, the new structurally compliant chamber had a 134 or 287 percent increase in fatigue life, depending on the life predicted for the conventional configuration

New method of making advanced tube-bundle rocket thrust chambers

An improved method of fabrication rocket chambers for future space applications is described. Included are fabrication demonstrator and test chambers produced by this method. This concept offers the promise of improved cyclic life, reusability, and performance. The performance is improved because of the enhanced enthalpy extraction. The improved cyclic life, reusability, and reliability is improved because of the structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber by a tube-bundle of high conductivity copper or copper alloy tubes and the bonding of these tubes by a unique electroforming operation. Furthermore, the method of fabrication reduces chamber complexity by incorporating manifolds, and structural stiffeners while having the potential for thrust chamber cost and weight reduction

Hot fire test results of subscale tubular combustion chambers

Advanced, subscale, tubular combustion chambers were built and test fired with hydrogen-oxygen propellants to assess the increase in fatigue life that can be obtained with this type of construction. Two chambers were tested: one ran for 637 cycles without failing, compared to a predicted life of 200 cycles for a comparable smooth-wall milled-channel liner configuration. The other chamber failed at 256 cycles, compared to a predicted life of 118 cycles for a comparable smooth-wall milled-channel liner configuration. Posttest metallographic analysis determined that the strain-relieving design (structural compliance) of the tubular configuration was the cause of this increase in life

A New Genus of Eomyid Rodent from the Ogliocene Ash Spring Local Fauna of Trans-Pecos Texas

Contents: Abstract -- Introductions -- Meliakrouniomys new genus -- Description -- Discussion -- Meliakrouniomys wilsoni new species -- References CitedThis paper describes a new genus and species of eomyid rodent, Meliakrouniomijs tcilsoni, from the Ash Spring local fauna, the latest vertebrate faunule from the Vieja Group of Trans-Pecos Texas. The teeth indicate that it is an eomyid rodent in process of tooth pattern simplification. Resemblances in tooth pattern and jaw structure to heteromyids and eomyids suggest that Meliakrouniomys may represent a transitional stage between the two families.Texas Memorial Museu

Persistence of Residual Currents in the James River Estuary and its Implication to Mass Transport

The distribution and persistence of Eulerian and Lagrangian residual velocity in a cross sectional transect of the James River estuary, Virginia are analyzed. The Eulerian residual velocity has the characteristic two-layered estuarine circulation in the northern half of the transect, however, the net flow is directed downriver at all depths in the shallower southern half of the transect. In the deep channel, the two-layered Eulerian residual circulation is highly persistent over the six month study duration, with disruptions occurring less than 10% of the time when meteorological forcings are intense. No spring-neap tidal cycle variation is apparent. The magnitude of the long-term advective mass transport (calculated as the lowest order approximation to the Lagrangian residual velocity) is approximately twice that of the Eulerian residual velocity and in the same direction in the deep channel. The Stokes drift velocity contribution to the Lagrangian residual velocity enhances the upriver Eulerian residual velocity transport on the north side of the transect and only slightly increases the downriver transport on the south side.https://scholarworks.wm.edu/vimsbooks/1171/thumbnail.jp

Improving the responsiveness of Kitwe City Council to the needs of the stakeholders

This report is centred on the responsiveness of the KCC to the needs of the stakeholders in the city. It arose from the 2nd SINPA workshop at which a strategy for building capacity within the KCC was developed. Responsiveness was identified at this workshop as a priority area where capacity building was required in the KCC. The report has highlighted the importance of responsiveness in urban governance and the critical role that participatory decision making plays in good urban governance. It has defined responsiveness as the extend to which the KCC operates in a demand oriented manner and also the extent to which KCC performs satisfactorily in the eyes of the stakeholders. Therefore, the core of the work is centered on investigating the extent to which the KCC programmes and activities are rooted in the needs and priorities of the stakeholders. The main stakeholders have been identified as: the residents of the city; the business community and the NGOs. The TORs of the report were: (1) To identify and assess the existing structures vis-a vis responsiveness and to what extent they work in identifying the needs and priorities of the stakeholders and whether these are used in development planning by the KCC and; (2) To formulate recommendations to improve the existing structures or recommend new ones where necessary and to suggest ways in which SINPA Zambia can contribute to follow-up