Martin P. Sherman

Bio: Martin P. Sherman is an academic researcher from Princeton University. The author has contributed to research in topics: Arcjet rocket & Heat transfer. The author has an hindex of 2, co-authored 5 publications receiving 111 citations.

Calorimetric Probe for the Measurement of Extremely High Temperatures

Abstract: A water‐cooled gas sampling probe capable of steady‐state operation at 15 000°K and one atmosphere has been developed. Temperature is measured by a calorimetric technique which can provide high‐accuracy calibration under arcjet conditions. The probe also measures velocity and chemical composition and, because of its small size (∼⅛ in. o.d.), is capable of accurate local measurements in the presence of severe gas‐stream property gradients. Calibrations in the partially ionized argon‐helium environment of an arcjet exhaust indicated an average agreement with mass and energy balance criteria within ½%, and a standard deviation from the mean of less than 3%.

Laminar arcjet mixing and heat transfer - Theory and experiments.

Abstract: Laminar argon arcjet mixing with coaxial flow of cool helium, considering turbulent characteristics and heat transfer

A Collimated Total Radiation Probe for Arcjet Measurements

Abstract: The total energy radiation of an argon arcjet was measured by a simple collimated thermopile. Radiation from the luminous jet was found to vary as T7.2 when the peak (centerline) temperature at the arcjet exit plane was 12,600°K. Total radiated energy from the arcjet, including the downstream-directed component from the cathode face, was found to agree quite well with theoretical estimates given in the present paper. The use of a purified helium atmosphere and lithium fluoride optical components permitted achievement of transmissivity down to 1060 angstroms on all measurements.

Heat Transfer from a Partially Ionized Gas to a Gaseous Coolant

Abstract: : Theoretical and experimental studies were made of subsonic mixing between a partially-ionized gas jet and a cool, coaxial gas flow. The gases studied were argon and helium. Both turbulent and laminar mixing regimes were investigated. In the turbulent mixing study, analytical expres sions were closely verified by experiment. In laminar mixing, theoretical transport properties were computed and used to analyze the laminar mixing case.

Laminar mixing and heat transfer phenomena between a partially ionized gas and a gaseous coolant

Abstract: : Mixing and heat transfer characteristics of a laminar subsonic argon arcjet issuing into a stagnant atmosphere of room-temperature helium were investigated by a combined analytical-experimental approach. The analysis was based on classical continuum theory utilizing the boundarylayer approximation. Good correlation between theory and experiment was observed. Although the departure from equilibrium between the electrons and the heavy particles was estimated to be sufficiently small when considering the overall mixing process, it was shown analytically that this equilibrium probably did not exist in the regions of highest temperature gradient. It was, therefore, decided to explore the nature of this departure in the high-density (one atmosphere) collision-dominated, partly-ionized gas by the use of a cooled electrostatic probe. The theory for such a probe was formulated, and it appears to provide the capability for measuring both electron concentrations and electron temperatures.

Entrainment of cold gas into thermal plasma jets

Abstract: There is increasing evidence that the entrainment of cold gas surrounding a turbulent plasma jet is more of an engulfment type process rather than simple diffusion. A variety of diagnostic techniques have been employed to determine the development of turbulence in a plasma jet and to measure concentration and temperatures of the cold gas entrained into atmospheric-pressure argon plasma jets in ambient argon or air. The results indicate that the transition to turbulence causes a rapid drop of the axial jet velocity due to entrainment of the cold gas surrounding the plasma jet. Dissipation of the cold engulfed gas bubbles by molecular diffusion is relatively slow if molecular gases (for example air) are entrained, as indicated by conditional sampling and CARS measurements. Temperature measurements using emission spectroscopy and enthalpy probes show strong discrepancies in the jet fringes.

Fundamental studies associated with the plasma spray process

Abstract: More than 25 years ago, plasma spraying was established as a commercial process, but only recently have serious attempts been reported to establish a solid scientific base for this technology. The first part of this paper refers to the basic processes involved in plasma spraying, including plasma generation, plasma jet formation, particle injection, particle heat and momentum transfer, and particle deposition. In the second part, recent results obtained in this laboratory are summarized. These results are mainly concerned with the effects of vortex flow on particle motion and on air entrainment during atmospheric spraying.

Suspension Plasma Spraying: Process Characteristics and Applications

Abstract: Suspension plasma spraying (SPS) offers the manufacture of unique microstructures which are not possible with conventional powdery feedstock. Due to the considerably smaller size of the droplets and also the further fragmentation of these in the plasma jet, the attainable microstructural features like splat and pore sizes can be downsized to the nanometer range. Our present understanding of the deposition process including injection, suspension plasma plume interaction, and deposition will be outlined. The drawn conclusions are based on analysis of the coating microstructures in combination with particle temperature and velocity measurements as well as enthalpy probe investigations. The last measurements with the water cooled stagnation probe gives valuable information on the interaction of the carrier fluid with the plasma plume. Meanwhile, different areas of application of SPS coatings are known. In this paper, the focus will be on coatings for energy systems. Thermal barrier coatings (TBCs) for modern gas turbines are one important application field. SPS coatings offer the manufacture of strain-tolerant, segmented TBCs with low thermal conductivity. In addition, highly reflective coatings, which reduce the thermal load of the parts from radiation, can be produced. Further applications of SPS coatings as cathode layers in solid oxide fuel cells (SOFC) and for photovoltaic (PV) applications will be presented.

Bibliography of Temperature Measurement: July 1960 to December 1962

Abstract: Report presenting 700 additional references to the field of temperature measurement as a supplement to NBS Monograph 27, "Bibliography of Temperature Measurement, January 1953 to June 1960" issued April 6, 1961. These references were collected from two general sources: Scientific and technical literature and government reports. The period covered is from July 1960 to December 1962 with some earlier references which were found later. The arrangement of material is the same as in Monograph 27.