Electrical Conductivity in Flame Gases with Large Concentrations of Potassium

Abstract

The conductivity of the hot gases from propane-oxygen flames containing potassium has been measured in a coaxial graphite cell. In the temperature range 1800–2400°K with potassium concentrations of 0.01–1.0% by weight, the measured conductivity agrees with that calculated from the Saha equation and a ``free-path'' kinetic equation. A constant value of 1×10−15 cm2 was used as the cross section for collision between electrons and the combustion products in this calculation. At higher potassium concentrations, up to 7½% by weight, the electron-potassium atom cross section becomes important but a value of about 10−15 cm2 gives fair agreement with the data. At low temperatures and high cell voltages, current saturation resulting from the limited electron emissivity of the graphite was observed.

A discussion on advanced methods of energy conversion- Magnetohydrodynamic power generation - Equilibrium and non-equilibrium electrical conductivity of seeded combustion products

“…This reduces the density of electrons given by a certain quantity of free potassium atoms. Kantrowitz, Rosa & Stekly (1961); O, Brogan (1962); V, Jones & McKinnon (1962); □, Jones et al (1963); A, Mullaney et al (1961); O, Zimin & Papov (1962); c tion in air; +, present work; curve 2, theoretical.…”

“…A value of the electron affinity of nitrogen dioxide of 3 6 eV formed the basis of their suggestion but it would require only a small error in this value, say, a change to 3 3 eV to make the effect of nitrogen dioxide ions negligible. The high values of conductivity obtained by Mullaney, Kydd & Dibelius (1961) may have been due to the very fuel-rich nature of the combustion products and the presence of large amounts of burning carbon in their experiments. The conclusion may be drawn from the foregoing discussion that if Frost's method of calculating conductivities in the combustion products of pure hydrocarbon fuels is adopted with a value of 21 eV for the electron affinity of the hydroxyl radical the values obtained will be satisfactory for high temperatures but some 30% to 40 % too low at low temperatures.…”

“…The theoretical curve shown in figure 4 was calculated by considering an equilibrium of potassium, potassium ions, electrons, potassium chloride, potassium hydroxide, hydroxyl ions and chlorine ions. The equilibrium constants for potassium chloride were taken from the JANAF tables, for chlorine ions and hydrogen chloride from Mullaney & Dibelius (1963), and for hydroxyl ions (2*1 eV electron affinity), potassium hydroxide, and the ionization of potassium, from Frost (1961). The shape of the theoretical curve follows the experimental results but predicts lower actual values than the experimental points.…”

Calculation of the D-C Electrical Conductivity of Equilibrium Nitrogen and Argon Plasma With and Without Alkali Metal Seed

“…In a slightly more general form, Eq. (6) may be written, 0.532 n e e 2 (~Q )_1 a = "" nj ej me %(kT) % Equation (7). except for the numerical coefficient, can also be derived by the so-called "free-path kinetic theory" in which it is assumed that the particles make instantaneous collisions with each other but move freely between collisions.…”

Total Electron—Atom Collision Cross Sections at Low Energies—A Critical Review

“…Chen (1963) Harris (1963) Frost and Phelps (1964) Cromptom, Elford, and Jory (1967) Tice and Kivelson ('1967a Hoffmann and Skarsgard (1969) Phelps, Fundingsland, and Brown (1951) Gilardini and Brown (1957) Bowe (1960) Harris (1963) Chen (1964) Hoffmann and Skarsgard (1969) Phelps, Fundingsland, and Brown (1951) Bowe (1960) Harris (1963) Frost andPhelps (1964) Tice and Kivelson (1967a) Phelps, Fundingsland, and Brown (1951') Bowe (1960) Chen (1963) Frost and Phelps (1964) Hoffmann and Skarsgard (1969) Phelps, Fundingsland, and Brown (1951) Bowe (1960) Chen (1963) Frost and Phelps (1964) Hoffmann and Skarsgard (1969) Mullaney and Dibelius (1961) Mirlin, Pikus and Yurev (1962) Chen and Raether (1962) Morgulis and Korchevoi (1963) Flavin and Meyerand (1963) Roehling (1963) Harris (1963) Polushkin and Dudko (1966) Nighan (1967) w k BEDKRsoN AND KIrzzER I~lectron -Ato~n CoQision Cross Sections ut I-ozv i"nergies ACKNOWLEDGMENTS We would like to thank the many individuals who assisted us in the preparation of this paper. Specifically we wish to thank Dr. A. V. Phelps, Dr. G. C. Baldwin, Dr. E. Rothe, Dr. R. Neynaber …”