### Topics

### features

### Publications

### Issue Archive

# Unique and Secure Anti-Counterfeit Technology for Multiple Industries

Friday, 01 September 2006

# An Operational Guide to Bringing Your Invention to Market

Friday, 01 September 2006

The last of a four-part series on converting your invention into a revenue-generating business, this month’s article describes, from an operational viewpoint, the critical steps that an inventor needs to understand to raise investment money and convert their invention into a viable business.

Read More >>

Posted in: Articles

Read More >>

# 30 Years of Power & Energy

Friday, 01 September 2006

In celebration of the 30th Anniversary of NASA Tech Briefs, our features in 2006 highlight a different technology category each month, tracing the past 30 years of the technology, and continuing with a glimpse into the future of where the technology is headed. Along the way, we include insights from industry leaders on the past, present, and future of each technology. This month, we take a look at the past 30 years of Power & Energy Technology.

Read More >>

Posted in: Articles

Read More >>

# Thermal Model of a Current-Carrying Wire in a Vacuum

Friday, 01 September 2006

A computer program implements a thermal model of an insulated wire carrying electric current and surrounded by a vacuum. The model includes the effects of Joule heating, conduction of heat along the wire, and radiation of heat from the outer surface of the insulation on the wire. The model takes account of the temperature dependences of the thermal and electrical properties of the wire, the emissivity of the insulation, and the possibility that not only can temperature vary along the wire but, in addition, the ends of the wire can be thermally grounded at different temperatures. The resulting second-order differential equation for the steady-state temperature as a function of position along the wire is highly nonlinear. The wire is discretized along its length, and the equation is solved numerically by use of an iterative algorithm that utilizes a multidimensional version of the Newton-Raphson method.

Read More >>

Posted in: Briefs, TSP

Read More >>

# Compressible Flow Toolbox

Friday, 01 September 2006

The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number >1. The toolbox also contains algorithms for comparing and validating the equation- solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows:
The isentropic-flow equations,
The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction),
The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section),
The normal-shock equations,
The oblique-shock equations, and
The expansion equations.

Read More >>

Posted in: Briefs, TSP

Read More >>

# Code for Multiblock CFD and Heat-Transfer Computations

Friday, 01 September 2006

The NASA Glenn Research Center General Multi-Block Navier-Stokes Convective Heat Transfer Code, Glenn- HT, has been used extensively to predict heat transfer and fluid flow for a variety of steady gas turbine engine problems. Recently, the Glenn-HT code has been completely rewritten in Fortran 90/95, a more object-oriented language that allows programmers to create code that is more modular and makes more efficient use of data structures. The new implementation takes full advantage of the capabilities of the Fortran 90/95 programming language. As a result, the Glenn-HT code now provides dynamic memory allocation, modular design, and unsteady flow capability. This allows for the heat-transfer analysis of a full turbine stage. The code has been demonstrated for an unsteady inflow condition, and gridding efforts have been initiated for a full turbine stage unsteady calculation. This analysis will be the first to simultaneously include the effects of rotation, blade interaction, film cooling, and tip clearance with recessed tip on turbine heat transfer and cooling performance. Future plans call for the application of the new Glenn-HT code to a range of gas turbine engine problems of current interest to the heat-transfer community. The new unsteady flow capability will allow researchers to predict the effect of unsteady flow phenomena upon the convective heat transfer of turbine blades and vanes. Work will also continue on the development of conjugate heat-transfer capability in the code, where simultaneous solution of convective and conductive heattransfer domains is accomplished. Finally, advanced turbulence and fluid flow models and automatic gridding techniques are being developed that will be applied to the Glenn-HT code and solution process.

Read More >>

Posted in: Briefs, TSP

Read More >>

# General Flow-Solver Code for Turbomachinery Applications

Friday, 01 September 2006

Phantom is a computer code intended primarily for real-fluid turbomachinery problems. It is based on Corsair, an ideal-gas turbomachinery code, developed by the same authors, which evolved from the ROTOR codes from NASA Ames. Phantom is applicable to real and ideal fluids, both compressible and incompressible, flowing at subsonic, transonic, and supersonic speeds. It utilizes structured, overset, O- and H-type zonal grids to discretize flow fields and represent relative motions of components. Values on grid boundaries are updated at each time step by bilinear interpolation from adjacent grids. Inviscid fluxes are calculated to thirdorder spatial accuracy using Roe’s scheme. Viscous fluxes are calculated using second-order-accurate central differences. The code is second-order accurate in time. Turbulence is represented by a modified Baldwin-Lomax algebraic model. The code offers two options for determining properties of fluids: One is based on equations of state, thermodynamic departure functions, and corresponding state principles. The other, which is more efficient, is based on splines generated from tables of properties of real fluids. Phantom currently contains fluid-property routines for water, hydrogen, oxygen, nitrogen, kerosene, methane, and carbon monoxide as well as ideal gases.

Read More >>

Posted in: Briefs, TSP

Read More >>

### White Papers

| ||||||