Engineering topics

Phillips, J. R.

Publications and source records attributed to Phillips, J. R..

5 records

NASA NTRS2018

Electrostatic Precipitation for Cleaning Mars Atmospheric ISRU Intakes

Future Mars ISRU atmospheric intakes are estimated to ingest several hundred grams of dust over their lifetime. The Electrostatics and Surface Physics Laboratory at NASA's Kennedy Space Center is developing a dust removal system based on a mature terrestrial technology - electrostatic precipitation. In this technology, a high voltage and grounded collection electrode create a corona discharge which charges particles in a dust-laden flow. The resulting electric field between the high voltage and collection electrodes drive the charged particles toward the collection electrode. This paper presents the design of the electrostatic precipitator and preliminary results.

Precipitator↗

NASA NTRS1996

Error and Complexity Analysis for a Collocation-Grid-Projection Plus Precorrected-FFT Algorithm for Solving Potential Integral Equations with LaPlace or Helmholtz Kernels

In this paper we derive error bounds for a collocation-grid-projection scheme tuned for use in multilevel methods for solving boundary-element discretizations of potential integral equations. The grid-projection scheme is then combined with a precorrected FFT style multilevel method for solving potential integral equations with 1/r and e(sup ikr)/r kernels. A complexity analysis of this combined method is given to show that for homogeneous problems, the method is order n natural log n nearly independent of the kernel. In addition, it is shown analytically and experimentally that for an inhomogeneity generated by a very finely discretized surface, the combined method slows to order n(sup 4/3). Finally, examples are given to show that the collocation-based grid-projection plus precorrected-FFT scheme is competitive with fast-multipole algorithms when considering realistic problems and 1/r kernels, but can be used over a range of spatial frequencies with only a small performance penalty.

Phillips, J. R.↗

NASA NTRS1996

Pasma Wave Characteristics of the Jovian Magnetopause Boundary Layer: Can Wave-Particle Interactions Cause the Jovian Aurora?

The full Jovian magnetopause boundary layer (BL) plasma wave spectra from 10(sup -3) to 10(sup 3) Hz, have been measured for the first time...The B'/E' ration does not have a f(sup -1) dependency, so it was suggested that the waves are a mixture of whistler mode electromagnetic emissions and electrostatic waves.

jovian magnetosphere Jupiter Jovian magnetopause E↗

NASA NTRS1978

Performance investigations of liquid-metal heat pipes for space and terrestrial applications

The high heat transfer capacity of liquid-metal heat pipes is demonstrated in performance tests with mercury, potassium, sodium, and lithium working fluids and wick structures which serve to minimize liquid pressure losses and vapor/liquid interactions. Appropriate wicks for horizontal and vertical operation are described. It is shown that heat-transfer with these wicks is limited by vapor flow effects. Examples are given of particular effects associated with a long adiabatic section between evaporator and condenser and with a heat source of uniform temperature as opposed to a source of uniform power.

Kemme, J. E.↗

NASA NTRS1976

Limitations on the use of laser velocimeter signals for particle sizing

The paper discusses the complex relationship existing between the diameter of a particle, its index of refraction, and the output signal of a fringe-type laser velocimeter, and describes a special purpose laser velocimeter for aerosol sizing that determines aerosol size distributions on the basis of Farmer's (1973) relationship between visibility and particle size. In experiments with particles of known size, this relationship is in qualitative agreement with the experimentally observed results, the main differences being that (1) the visibility does not assume a minimum value of zero, as predicted, and (2) the visibility value above which there is no ambiguity in the corresponding fringe spacing is higher than that predicted.

Orloff, K. L.↗