Engineering topics

Ferrall, Joseph F.

Publications and source records attributed to Ferrall, Joseph F..

5 records

NASA NTRS1994

Mathematical Modeling Of Life-Support Systems

Generic hierarchical model of life-support system developed to facilitate comparisons of options in design of system. Model represents combinations of interdependent subsystems supporting microbes, plants, fish, and land animals (including humans). Generic model enables rapid configuration of variety of specific life support component models for tradeoff studies culminating in single system design. Enables rapid evaluation of effects of substituting alternate technologies and even entire groups of technologies and subsystems. Used to synthesize and analyze life-support systems ranging from relatively simple, nonregenerative units like aquariums to complex closed-loop systems aboard submarines or spacecraft. Model, called Generic Modular Flow Schematic (GMFS), coded in such chemical-process-simulation languages as Aspen Plus and expressed as three-dimensional spreadsheet.

Seshan, Panchalam K.↗

NASA NTRS1993

Life-Support-System Analyzer

Paper describes software system, called Generic Modular Flow Schematic (GMFS), developed for use in synthesis, mathematical modeling, and analysis of life-support systems aboard spacecraft, ranging from simple open-loop configurations to complex closed-loop ones. GMFS also compares alternative systems.

Seshan, Panchalam K.↗

NASA NTRS1991

Human life support during interplanetary travel and domicile. III - Mars expedition system trade study

Several alternative configurations of life-support systems (LSSs) for a Mars missions are compared analytically on a quantitative basis in terms of weight, volume, and power. A baseline technology set is utilized for the illustrations of systems including totally open loop, carbon dioxide removal only, partially closed loop, and totally closed loop. The analytical model takes advantage of a modular, top-down hierarchical breakdown of LSS subsystems into functional elements that represent individual processing technologies. The open-loop systems are not competitive in terms of weight for both long-duration orbiters and short-duration lander vehicles, and power demands are lowest with the open loop and highest with the closed loop. The closed-loop system can reduce vehicle weight by over 70,000 lbs and thereby overcome the power penalty of 1600 W; the closed-loop variety is championed as the preferred system for a Mars expedition.

Seshan, P. K.↗

NASA NTRS1991

Human life support during interplanetary travel and domicile. IV - Mars expedition technology trade study

Results of trading processing technologies in a closed-loop configuration, in terms of power and weight for the Mars Expedition Mission, are presented. The technologies were traded and compared to a baseline set for functional elements that include CO2 removal, H2O electrolysis, potable H2O cleanup, and hygiene H2O cleanup. These technologies were selected from those being considered for Space Station Freedom and represent only chemical/physical technologies. Attention is given to the technology trade calculation scheme, technology data and selection, the generic modular flow schematic, and life support system specifications.

Rohatgi, Naresh K.↗

NASA NTRS1988

Systems Analysis Of Advanced Coal-Based Power Plants

Report presents appraisal of integrated coal-gasification/fuel-cell power plants. Based on study comparing fuel-cell technologies with each other and with coal-based alternatives and recommends most promising ones for research and development. Evaluates capital cost, cost of electricity, fuel consumption, and conformance with environmental standards. Analyzes sensitivity of cost of electricity to changes in fuel cost, to economic assumptions, and to level of technology. Recommends further evaluation of integrated coal-gasification/fuel-cell integrated coal-gasification/combined-cycle, and pulverized-coal-fired plants. Concludes with appendixes detailing plant-performance models, subsystem-performance parameters, performance goals, cost bases, plant-cost data sheets, and plant sensitivity to fuel-cell performance.

Ferrall, Joseph F.↗