Arthur T. Mattick

HIGH-EFFICIENCY ENERGY CONVERSION SYSTEMS FOR LIQUID NITROGEN AUTOMOBILES

This investigation of the use of cryogens as energy storage media for zero emission vehicles has found that using liquid nitrogen to liquefy the working fluids of one or more closed Rankine power cycles can be an effective means for increasing motive power. System configurations are presented which can realize a specific energy greater than 400 kJ/kg-LN2 (110 W-hr/kg-LN2) without relying on isothermal expanders. A zero emission vehicle utilizing such a propulsion system would have an energy storage reservoir that can be refilled in a matter of minutes and a range comparable to that of a conventional automobile.

Results from current drive experiments on the Helicity Injected Torus

The Helicity Injected Torus [T. R. Jarboe, Fusion Technol. 15, 7 (1989)] is a low aspect ratio tokamak that is formed and sustained by coaxial helicity injection with no transformer. Toroidal plasma currents of over 200 kA have been achieved with electron temperatures in the 100 eV range and electron density between 1019 and 1020 m−3. The major radius is 0.3 m and the minor radius is 0.2 m. New results from equilibrium and stability analysis of the external magnetic diagnostics and new results from the Transient Internal Probe (TIP), an internal magnetic field diagnostic, are presented. A mechanism for the transfer of current drive on the open to the closed flux regions is presented.

Shock-Controlled Chemical Processing

A continuous-flow chemical reactor is described which uses shock waves to effect pyrolysis of hydrocarbons for the commercial manufacture of olefins. In this reactor, heat is added to an inert carrier gas, which is cooled to sub-pyrolysis temperatures by expansion to supersonic speed, and mixed with a supersonic flow of feedstock. Deceleration of the mixture by a standing shock wave initiates pyrolysis. Short reaction durations and high pyrolysis temperatures result in higher olefin yields than are attainable with conventional reactors. A simulation of ethane pyrolysis using the shock wave reactor predicts a 20% increase in ethylene yield and a 15% decrease in energy consumption compared to conventional reactors.

The transient internal probe: A novel method for measuring internal magnetic field profilesa)

The transient internal probe (TIP) diagnostic is designed to permit internal magnetic field measurements in hot, high density plasmas. A small probe is fired through the plasma at high velocities and magnetic field measurements are accomplished using Faraday rotation within the Verdet glass probe. Magnetic field resolution of ±40 G and spatial resolution of 5 mm have been achieved. System frequency response is 10 MHz. Ablative effects are avoided by minimizing both the probe size and the time the probe spends in the plasma. A two‐stage light‐gas gun is used to accelerate the probe (held by a sabot) to 2.2 km/s. The sabot is removed using gas dynamic forces and a gas interface system prevents the helium muzzle gas from entering the plasma chamber. Work is underway to integrate the TIP diagnostic with laboratory plasma experiments.

Magnetic field measurements using the transient internal probe (TIP)

The transient internal probe (TIP) is a novel diagnostic technique for measuring magnetic fields in hot plasmas. The concept involves shooting a diamond clad magneto‐optic probe through the plasma at high velocity allowing measurement of the local magnetic field before ablation occurs. Magnetic field measurements are obtained by illuminating the probe with an argon laser and measuring the amount of Faraday rotation in the reflected light. The diagnostic was tested by measuring a permanent magnetic field inside a vacuum chamber with a probe traveling at 2 km/s using an unclad probe. The purpose of this experiment was to demonstrate the capability of the TIP diagnostic and to verify compatibility with plasma vacuum requirements. Magnetic field resolutions of 20 G and 1 cm spatial resolution were achieved. The response time of the detection system is 10 MHz. Introduction of a helium muzzle gas into the plasma chamber was limited to less than 0.4 Torr l.

Coaxial radiative and convective heat transfer in gray and nongray gases

Coupled radiative and convective heat transfer is investigated for an absorbing gas flowing in a finite length channel and heated by blackbody radiation directed along the flow axis. The problem is formulated in one dimension and numerical solutions are obtained for the temperature profile of the gas and for the radiation escaping the channel entrance, assuming both gray and nongray absorption spectra. Due to radiation trapping, the flowing gas is found to have substantially smaller radiation losses for a given peak gas temperature than a solid surface that is radiatively heated to this temperature. A greenhouse effect is also evident whereby radiation losses are minimized for a gas having stronger absorption at long wavelengths.

Absorption and line-broadening of 12C18O2 at 2.7 μm

Pressure broadening coefficients have been measured for 12C18O2 at 2.7 μm broadened by buffer gas species CO2, H2, He, O2, N2, Ar, and Xe. The results, expressed as self-broadening efficiencies, are compared with data for other transitions from 1.6 to 10.4 μm.

Design and Experiments of a Continuous Rotating Detonation Engine: a Spinning Wave Generator and Modulated Fuel/Oxidizer Mixing

The continuous rotating detonation engine (CRDE) exploits shock-induced combustion in which reactants are ingested and burned by detonation shock waves spinning in an annulus. The high pressure and temperature behind the shock prompt rapid combustion of the fuel. The advantage of using detonation is a gain in total pressure. While deflagration burning always decreases total pressure, detonation burning increases total pressure. This gain is due to the combined effect of the static pressure rise across the shock and the increased motion of fluid behind it, ‘the blast wind’. The significance of total pressure increase is such that the CRDE itself serves as compressor stages, by converting a part of the chemical energy of the fuel directly to compression work. The CRDE acts a ‘bladeless compressor’, which could potentially reduce parts count of compressors and turbines. It is for this very reason why the CRDE is also called a pressure-gain combustor (PGC). At the more fundamental level, detonation is thermodynamically superior to deflagration because after combustion the entropy rise for a given heat input is lower for detonation than for deflagration. As in any heat engine, lower entropy rise leads to higher thermal efficiency, the intrinsic thermodynamic advantage of the CRDE. The paper starts with a survey of the past and recent progress made by many in developing the CRDE technology. With an aim to contribute to advancing further the CRDE technology, in this paper we present the design and experiments of a 14 cm diameter CRDE built and tested at the University of Washington (UW). The UW CRDE has two unique features: (1) direct detonation initiation by a spinning wave generator and (2) regulation of the mixing zone by modulated mixing of fuel/oxidizer.

Refractory clad transient internal probe for magnetic field measurements in high temperature plasmas

The transient internal probe (TIP) is a diagnostic for local internal field measurements in high temperature plasmas. A verdet material, which rotates the polarization angle of the laser light under magnetic fields, is launched into a plasma at about 1.8km∕s. A linearly polarized Ar+ laser illuminates the probe in transit and the light retroreflected from the probe is analyzed to determine the local magnetic field profiles. The TIP has been used for magnetic field measurements on the helicity injected torus where electron temperature Te⩽80eV. In order to apply the TIP in higher temperature plasmas, refractory clad probes have been developed utilizing a sapphire tube, rear disc, and a MgO window on the front. The high melting points of these refractory materials should allow probe operation at plasma electron temperatures up to Te∼300eV. A retroreflecting probe has also been developed using “catseye” optics. The front window is replaced with a plano-convex MgO lens, and the back surface of the probe is alu...

INTERNAL TOROIDAL FIELD MEASUREMENTS ON THE HELICITY INJECTED TOKAMAK USING THE TRANSIENT INTERNAL PROBE

Measurements of the local toroidal magnetic field have been achieved on the helicity injected tokamak (HIT) using the transient internal probe (TIP). HIT is a low aspect (a=1.5, R=0.35 m) ratio tokamak designed to study steady state current drive. The TIP diagnostic involves accelerating a small diamond clad magneto-optic probe through the plasma at high velocities (∼2 km/s) using a light gas gun. The local field is obtained by illuminating the probe with a laser and measuring the amount of Faraday rotation in the reflected beam. Measurements were conducted using unclad magneto-optic probes directed along a chord tangent to the toroidal field. Plasma conditions were typically ne∼7×1019 m−3 and Te∼40–80 eV. Measurement uncertainty is less than 2%. No changes in plasma parameters were observed during the first 200 ms (∼40 cm) of probe travel in the plasma. A temporary dip in plasma current, probably due to ablation of the retroreflecting material on the probe, is observed as the probe exits the plasma. Dens...