CONCERNING THE QUESTION OF SELECTIVE HEATING OF SMALL PARTICLES IN THE ULTRASHORT WAVE CONDENSER FIELD
H. Schaefer, H. Schwan · 1943
In water-in-oil emulsions, 2 mm droplets reached a 60° temperature rise at 5–10 kv/cm field strengths, enabling selective boiling, while microscopic particles remained far below a 1/1000° rise.
Plain English Summary
For the stationary case, a water-in-oil emulsion with optimum droplet conductivity at field strengths of 5–10 kv/cm produced a 60° average temperature rise in 2 mm diameter particles, making selective boiling dispersal possible. The non-stationary starting process showed a possibility of a considerable rise in relative particle temperatures above the stationary achievable high temperatures. For microscopic and colloid-dispersed dimensions, achievable temperature rises remained far below 1/1000°, limiting practical use to macroscopic systems. A medical-therapeutic usage possibility was mentioned briefly.
Why This Matters
The problem was divided into a stationary equilibrium condition where heat generated in the particle flows completely into the surrounding medium, and a preceding starting process where the heat generated initially is great then drops to zero as the particle heats. High temperatures were only significant relative to the suspension medium when the dispersing phase had much greater effective conductivity and particle diameters were in the millimeter range or larger. The stationary case was experimentally examined in the condenser field of a strong short wave sender at 11 m wavelength, confirming the theoretical evaluation. The field strengths needed for selective boiling dispersal of water droplets were only slightly below the dispersal field strengths from static fields. A macroscopic model system with an initial process lasting almost an hour was measured in detail for its spatial and temporal temperature distribution.
Finding
The average particle high temperature, in the extremely favorable system of water-in-oil emulsion with optimum conductivity of the water of the droplets at field strengths of 5... 10 kv/cm, reaches 60° for particles of 2 mm diameter and thus makes a selective boiling dispersal of the water droplets possible.
In their words
“The average particle high temperature, in the extremely favorable system of water-in-oil emulsion with optimum conductivity of the water of the droplets at field strengths of 5... 10 kv/cm, reaches 60° for particles of 2 mm diameter and thus makes a selective boiling dispersal of the water droplets possible.”
Show BibTeX
@article{concerning_the_question_of_selective_heating_of_small_particles_in_the_ultrashor_g6980,
author = {H. Schaefer and H. Schwan},
title = {CONCERNING THE QUESTION OF SELECTIVE HEATING OF SMALL PARTICLES IN THE ULTRASHORT WAVE CONDENSER FIELD},
year = {1943},
}