ISS Water Recovery System, Vapor Compression Distillation Process in Microgravity
No abstract available
Carter, Layne↗
Engineering topics
Schunk, Greg
Publications and source records attributed to Schunk, Greg.
Computer Simulation and Modeling of CO2 Removal Systems for Exploration
No abstract available
Coker, Robert↗
Unified CFD Methods Via Flowfield-Dependent Variation Theory
This paper addresses the flowfield-dependent variation (FDV) methods in which complex physical phenomena are taken into account in the final form of partial differential equations to be solved so that finite difference methods (FDM) or finite element methods (FEM) themselves will not dictate the physics, but rather are no more than simply the options how to discretize between adjacent nodal points or within an element. The variation parameters introduced in the formulation are calculated from the current flowfield based on changes of Mach numbers, Reynolds numbers, Peclet numbers, and Damkohler numbers between adjacent nodal points, which play many significant roles such as adjusting the governing equations (hyperbolic, parabolic, and/or e!liptic), resolving various physical phenomena, and controlling the accuracy and stability of the numerical solution. The theory is verified by a number of example problems addressing the physical implications of the variation parameters which resemble the flowfield itself, shock capturing mechanism, transitions and interactions between inviscid/viscous, compressibility/incompressibility, and laminar/turbulent flows.
Chung, T. J.↗
Parallelization of the Flow Field Dependent Variation Scheme for Solving the Triple Shock/Boundary Layer Interaction Problem
A parallelized version of the Flowfield Dependent Variation (FDV) Method is developed to analyze a problem of current research interest, the flowfield resulting from a triple shock/boundary layer interaction. Such flowfields are often encountered in the inlets of high speed air-breathing vehicles including NASA's Hyper-X. In order to resolve the complex shock structure and to provide adequate resolution for boundary layer computations of the convective heat transfer from surfaces inside the inlet, models containing over 500,000 nodes are needed. Efficient parallelization of the computation is essential to obtaining the results in a timely manner. Results from different parallelization schemes, based upon multi-threading and message passing, as implemented on multiple processor supercomputers and on distributed workstations are compared.
Schunk, Greg↗
Design of Large Lightweight Space Telescope Optical Systems for the Next Generation Space Telescope
The Next Generation Space Telescope (NGST) is currently in a Pre Phase A study effort to prove feasibility of design and to show that the design can be implemented within cost constraint guidelines and meet the requirements of the science community. In an effort to achieve the science communities goals as outlined in "HST and Beyond" the NGST team has developed a government "yardstick" design of an eight meter diameter segmented telescope which would be launched in an Atlas IIAS launch vehicle to a L2 (Lagrange Point) orbit. This paper will discuss the design of the Optical Telescope Assembly (OTA) and the various issues and complications of designing lightweight optics to be placed in the environment that the NGST will encounter both during launch and during its operational mission at L2. The OTA must be lightweight but structurally must withstand the launch environment and transfer to its final L2 orbit. The OTA must be stable at L2 to provide high quality science at the cryogenic temperatures it will experience. The OTA segmented petal concept is to develop lightweight optics which can either be manipulated to achieve and maintain a desired figure or be rigid enough so that change in shape is only necessary for phasing and alignment. The secondary mirror structural mast must also be rigid with frequency responses which are not coupled to spacecraft modes in order to maintain and decenter and despace requirements.
Jacobson, Dave↗
ECLS resupply for Space Station Freedom
The design of logistics carriers is presented emphasizing the use of cost-effective pressurized and nonpressurized versions to resupply consumable fluids and provide on-orbit support for the Space Station Freedom. The requirements for the Environmental Control and Life Support (ECLS) system include high-pressure oxygen and nitrogen as well as consumables that do not require pressurization. The nominal and contingency requirements are given for logistics carriers designed to support various mission scenarios by resupplying and servicing fluid systems on-orbit. The resulting design overview for the logistics carriers describes the cryogenic-nitrogen storage during launch and operation of the unpressurized version and the flexible payload-support capacity of the pressurized version. The carriers are characterized as lightweight and versatile, and the resupply of cryogenic nitrogen is a flight-proven capability.
Higginbotham, Keith↗