An investigation of flow in and around an induction plasma is made as a continuation of an earlier theoretical study of magnetic pressure in an induction plasma. The existence of the predicted flow out from both ends of the plasma is confirmed by flow visualization and stagnation pressure measurements in and around an ambient-pressure vortex-free argon plasma in a 28-mm tube. Flow visualization and gas velocities are obtained by photographing injected solid particles. For a 3-kW argon discharge, the velocity at the upstream end of the plasma was 6±0.3 m/sec, and velocity varies linearly with discharge power over the range investigated (up to 4.7 kW). A model of the plasma is devised to enable the maximum velocity of magnetically pumped flow to be calculated from the static magnetic pressure. Pressures in the range of +0.04 in. water, caused by expansion thrust of hot gases from the torch, were measured behind the plasma. The thrust pressure is calculated and is in reasonable agreement with measurements. A consequence of both magnetic and thrust pressures is that material introduced at the back of the torch tends to bypass the plasma.

Gas holdup in a tubular reactor was measured at pressures from 5 to 14 MPa at 300°C using a differential pressure cell. The effects on gas holdup of gas density, liquid superficial velocity and gas superficial velocity were studied using vacuum tower bottoms from a Venezuelan feedstock with 95.1 wt% +524°C material. Hydrogen was used at superficial gas velocities from 0.7 to 2.0 cm/s. The feed density at 15°C (0.1 MPa), 300°C (5.57 MPa) and 400°C (13.9 MPa) was measured and showed a linear decrease with temperature. Increased gas density at a constant temperature of 300°C increased the gas holdup at all superficial gas velocities. An increase in the liquid flow rate from about 0.04 to 0.1 cm/s did not affect the gas holdup.

Operating characteristics of an atmospheric-pressure, rf plasma torch and of its associated 30-kW power oscillator are inferred from available instrumentation and calorimetric heat balance measurements with various working fluids in torches of two diameters. The governing equations for the arc, neglecting convection, are derived and solved analytically for the crude channel-model approximation. Material functions for argon and nitrogen are then used to predict operating characteristics for these fluids. Fair agreement indicates that at least some of the essential physical phenomena of the discharge have been resolved. The analysis serves to explain much of the ``art of operation'' with special emphasis on the concepts of coupling and impedance matching.

Some properties of carboxylic acids are reviewed, with emphasis on recent experimental data. Qualified, consistent latent heat of vaporization data were developed for the series and a twopopulation viewpoint is suggested. The equation of state formulated by Grenzheuser [ I] is also recommended as a practical tool, and its further development is urged.

The pinch effect or excess magnetic pressure is calculated and measured for an rf induction plasma in argon. This excess magnetic pressure (Pm), which hitherto has been overlooked in all previous investigations concerning the induction plasma, explains the reported anomalous flow behavior of the plasma torch. Theory for calculating Pm is given using a model of the plasma as a solid conductor of constant electrical conductivity. From current density and magnetic field distribution within the plasma, the local Lorentz force is evaluated, and summation across the plasma radius gives the maximum Pm at the center of the peripheral discharge path. Published values for coupling efficiency and temperature profile are employed in conjunction with measured oscillator circuit parameters in order to make the calculation. The calculated Pm at the center of a 4.7 MHz, 2.5 kW argon induction plasma in a 30 mm tube is 64.5 dyn/cm2. At the center of the plasma, Pm was measured with a cooled probe and found to be 71.5±3 dyn/cm2. Although Pm/P≈10−4, the magnetic pressure has an appreciable effect on the fluid mechanics of the discharge. The pinch or compressive force acts inward around the circumference, but not at the ends of the cylindrical plasma. Consequently, a magnetically induced flow occurs out from both ends of the plasma.